In our continuing series of quick tips and tricks you can use to tweak and optimize your home theater or even your audio system we're going to talk a little bit about generic speaker placement, things for your main left and right speakers if it's stereo, or your front left and right mains if it's a home theater, and also a little bit that you can do with your seating and the room to make speakers sound better.

And I'm not talking about having to go out and spend lots of money on dedicated acoustic panels and treatments and things like that. These are things that either you already have in your room or that you might have available in your home that you can try out and test. And so, there's a few things that you can try that can make real significant improvements.

First, let's look at those front left and right speakers. Now, how close are they to the back wall? Are they closer than 4 inches, let's say from the back of the cabinet to the back of the wall? In that case, please, try pulling them out an inch or two. I'm not talking a ton.

I know a lot of people aesthetically don't want the speakers sitting out in the room and being so objectionable sitting out there, but try pulling them just a couple of inches further away from the back wall. And listen, listen before you do that, and after, and you'll probably notice a significant improvement in bass performance.

Similarly, if they're really, really close to the sidewalls of your room, try pulling them in just a little bit. Again, an inch or two can make a massive difference in bass performance and sometimes even imaging. In previous videos, I've talked about tow-in, that's how you angle the speakers in towards the listening position.

If you haven't tried that or played with that angle, do it now, check it out. Take the time to sit down and listen to some familiar music and try towing the speakers out or in if you've already got them angled, and see if you can get a better image focus, better definition. What's really good is something with a a solo vocalist that should be nicely centered in the mix and should be reasonable and realistic size as if it was a real person singing in front of you in your room.

Now, if you've got a home theater setup, one thing that many people don't realize is that the setup of the front three loudspeakers, ideally will be the same distance from your main listening position. What that means is that if you draw an arc from the front left to the center to the right main speaker, you should be along that arc, along that section of the circle.

What that means is that in distance terms, the distance from your center listening position to those three speakers should all be the same. And what that means is that the front left and right should be pulled slightly forward of the position of the center channel. So, try that if you haven't, it can give you a better, more seamless front soundstage in your home theater system.

Now, let's talk a minute about your seating. If you've got a sofa, is it right up against the back wall? In some cases, this is unavoidable, but if you have the opportunity to pull it forward half a foot or a foot from the rear wall so that there's a little bit of space between where you're sitting and the back wall.

That can really improve focus and definition of the system because you're now moving those reflections from your speaker output off the back wall to your ears, you're moving it further apart, and it can sound actually more open and more spacious just by moving your couch or your listening chair forward a foot or two.

Now, even if you're not bounded by the seating position is right up against the wall, try playing with it a little bit. If you're 8 feet from your speakers, try 7 feet, try 9 feet, move it a little bit, see what the bass does. Again, this is not costing you anything other than the effort of actually moving your furniture a little bit, and it's not a massive move just to listen, and see what the effect is.

All of these things are impacting the interaction of the loudspeaker and your listening position with the reflections in the room. So, small changes can make big differences.

Now, one final thing, if you've got hardwood or solid surface flooring in your main listening room or your home theater, and you don't have an area rug or any coverings on the floor at all, here's a real quick tip.

Take a carpet or rug, if you have an area rug available, and place it fairly close to the speakers centered between them, and listen again, I guarantee you that in most cases, getting rid of and damping that floor reflection from your main front speakers a little bit can lead to huge improvements.

Now, if you don't have an area rug or a small carpet hanging around, take a comforter off your bed, and try throwing it down in place of where you would have an area rug. Now, this is just a test, but listen before and after and see what happens.

The final thing, because we're talking about reflections is look at things that can interfere with the output from your front speakers between you and the listening position. Coffee tables try moving them if they're a hard surface like glass or wood, try moving it forward or back a few inches, you're modifying the reflection off of that surface between the speakers and yourself.

And again, it can make huge differences in the performance. It may seem silly, but all of these acoustic interactions play great importance on how good your system is going to sound. So, try some of those tips out if you've got time at home and you want to play around a little bit and see if you can make your existing system better.

It's not going to cost you anything, and it's easy to try. Let me know in the comments below whether or not you tried any of these things and if they made improvement or made things worse. Thanks a lot for watching.]]> Fri, 19 Jun 2020 14:17:20 +0000 https://www.axiomaudio.com/blog/receiver-set-up/

It's so confusing. So, I'm going to try to give you a couple of setup hints if you already have one of these receivers, some upgrade suggestions if your receiver is 10 or 15 years old, and things to look for if you're just starting out and going to be buying your first home theater system and an AVR or audio/video receiver.

What can you do now if you have an existing system? Number one, if you've used the automatic calibration or speaker setup, you know, where some of these systems you place a microphone in the room or in different spots near your listening position, and you press a button in the menu on the remote, and it automatically sets everything up for you.

Now, these systems are easily fooled. There's too much variation in the types of loudspeakers in rooms and the room setup that you can easily confuse these auto setup algorithms and systems. So, one hint, if you use that, go through the manual, and learn how to do the manual setup, and then go and try it yourself.

Many of these receivers will allow you to switch between the manual setting that you created and the auto setup so that you can hear the difference. In many cases, you'll find that the performance of your system is way better just using the manual setup and your ears. You don't need a sound level meter, if you have one, great, but, you know, the basic things about manual setup also let you understand the system better.

The settings the receiver's actually making rather than blindly pressing a button, and letting it do it for you. So, now the second thing that you want to look at once you've done that is check the levels, check the level adjustment. If all of the levels are above or below the trim level in the speaker settings, just make sure that you don't have too much spread.

A dB or 2 from the 0 dB trim position is good, but if something looks out of whack and everything is set up like -6 or -5 dB, or +6 or +8 dB, you know, you want to correct that. Because you can overdrive or underdrive things, you want to be as close to that neutral 0 dB trim setting.

Now, a lot of you are going, "What the heck is he talking about trim setting?" Just look at your manual, go online if you don't have a paper copy, you'll see what I'm talking about when it comes to the manual speaker setup.

Now, another thing if you're using an auto EQ or correction system that comes along with some of these automatic speaker setups in these receivers, like Odyssey is a very popular one.Try if the option is available of only applying room correction or equalization at bass frequencies. Many of these systems will allow you to specify what range of frequencies that auto EQ or room correction will work in. You will find if you've got a good quality loudspeaker system that you don't want to apply EQ or correction above maybe 200 hertz, turn it off if you can.

Try it both ways and see which ones you prefer, but I guarantee you with a good set of speakers, with a good setup, you're not going to want to equalize, above a couple hundred hertz. So, now what if you've had your home theater receiver for a while?

You know, what should you look for in terms of, you know, an upgrade, and when's a good time to upgrade? Well, this receiver here is a weird hybrid because it came around the same time that HDMI was starting to be introduced, but it also has component video, an old S-video connections.

Now, if your receiver is old enough that it only has component and S-video and there's no HDMI, that's a red flag that you should look at upgrading your AVR. Seriously. It will cut down immensely on that stress of all those connections, and it turns it into one cable per component which is really, really fantastic.

If your receiver doesn't have HDMI connections, then don't hesitate to look at upgrading your receiver.

Another thing that you want to look at in an update is obviously make sure that your receiver, if you're going to upgrade it, has the latest format for decoding which right now is Dolby Atmos.

I wouldn't even consider buying a brand new receiver today if it didn't have Dolby Atmos capability. So, make sure that that's available. Now, almost every receiver on the market is going to have Dolby Atmos, so you don't really have to worry about that.

Another thing if you're planning an upgrade, even if you've got the features basically you want, but you want to upgrade the component, look at going with something that has higher built-in amplifier power, or make sure that the receiver has got what are called pre-outs, which are preamplifier outputs.

Even if you're not going to use an external amplifier today, it gives you an excellent upgrade path should you upgrade your main speakers and require more power than is built into the receiver. It builds in a certain level of not obsoleting the entire receiver because you now suddenly need more amp power.

You can always add an external amplifier if you've got those pre-outs. And I always recommend that you won't find preamps on the cheapest receivers out there. You have to go to sort of the mid and the higher end of any product line from a particular manufacturer, but it's well worth the investment. I've had people say, I would have had to essentially sell a receiver I paid $2,000 for a couple of years ago because I needed more power with my new speakers, and now I just had to add an amplifier and kept the receiver the way that it was.

That's another area where it's a good recommendation if you're going to upgrade and spend the money anyway, look at getting something with pre-outs.

Now, the final thing that I want to suggest, if you're just starting out and you've got a small loudspeaker setup, you know, it's all bookshelf speakers or smaller speakers, there's really no need to jump into, you know, a very, very expensive home theater receiver.

And I'll tell you why, even though it gives you some path to upgrade, the problem is that the electronic systems in these receivers is constantly evolving. And you can be caught, you know, buying an expensive receiver saying, well, I'll just keep that, and then upgrade my speakers in four or five years, and then find in four or five years, Dolby or whoever has a brand new format that, you know, your current receiver is not capable of.

So, you know, think about that a little bit. If it's a first system, an entry-level receiver from a decent brand is a good way to go. There's no need to go with the highest amplifier power if you've got small bookshelf speakers or smaller speakers for your home theater system.

And definitely think about the future, but also think about what's viable in terms of where your upgrade path is going to go. It doesn't make sense, like I said, to buy a $1,500 or $2,000 top-line receiver, and then use it forever with a small speaker system. It would be better to take some of that budget and go with bigger or better loudspeakers, and settle for a little while with a more mid-range receiver.

I hope those helps and tips are a few things you can check out and, you know, have taken a little bit of the fear out of all these connections. Like I said, in this day and age of HDMI, it's one cable per component, and then one pair of speaker cables for every speaker, and you're pretty much done.

Most of this mess goes away.

You've got boundaries here, you've got a wall, you've got sidewalls, and you're going to get reasonable reinforcement from those boundaries, which are going to help with bass and help with the sensitivity and the efficiency or perceived level of the speaker for a given amplifier power. Now, why this is important is that when you've got the speakers in a room, a lot of the efficiency that you get is because of the boundary loading because of the reflections that are in the room.

If we have a pair of outdoor speakers that are truly in free space so that they're not mounted against any boundary or near any walls, the perceived level for a given amount of amplifier power goes down significantly. So you need to keep that in mind. If you're going to be trying to fill a large open patio space with a pair of speakers, even if they're mounted up against one wall boundary, you're going to actually have to have more amplifier power available for whatever listening level you're looking to achieve than you would in a typical living room or family room.

So, don't skimp on amplifier power just because it's an outdoor system. Unless you're going to be listening just at the quietest background levels, you may find you need more amplifier power than you think. One other thing to keep in mind is sound doesn't travel very well at some frequencies in open space.

And it's again because you don't have this enclosed environment of a room. So, having multiple outdoor speakers rather than just a single pair of speakers is better if you're trying to fill a large open area with good sound quality. Now, one thing to keep in mind, in an environment like this where you've got a room that's maybe 12 or 15 feet wide, you're still going to get some good sense of stereo reproduction.

And in environments where you're placing the speakers as far apart as you would in a typical listening room, you can still expect to get good stereo sound. But we have to think about that a little bit if you're trying to fill a large open space with sound. Stereo actually can be a detriment in those cases. And what you might want to think of doing is actually running a model setup, which can be done in software if you're using digital files and some preamplifiers and processors have a mono setting that you can use.

This essentially will mix the left and right information into all of the speakers, so you get an environment where you get a good spread of sound, and you're not worried about stereo separation, which can be weird if you have some instruments in the left speakers and some instruments in the right speakers. Another thing with digital files that's very easy is something called normalizing.

That's something that you might want to do if you're using iTunes for instance, you might want to keep a version of your library available for outdoor use that's normalized. That's just going to compress the levels so that what happens is that if you've got a recording that's got very, very quiet parts, it will bring them up. Those quiet parts usually would be completely inaudible in an outdoor situation.

So, there's a few things to think about when you're setting up positioning and thinking about purchasing your outdoor speakers.

Let's talk about the surround channels or the effects channels or the rear channels, however you want to say them. They're the speakers that handle the information that is either to the side of you or behind you, depending on how many channels you have in your configuration.

The sort of minimal home theater configuration 5.1, there are two rear surround or effects channels. Now, I will warn you, one of the things about the tips that I'm going to give you, this is just based on my personal experience over years of setting up and listening and tweaking these sorts of systems.

I'm not going to follow exactly what THX or Dolby or anyone else says because personally, I've found that you can get good results by using a mix of, you know, what I've learned over the years and, you know, what the official positions from these companies are.

So, let's start off with a surround speaker like the Axiom QS8 that I have here. Now, in a 5.1 system, as I said, you'll have two rear channels. In a 7.1 system, you'll have two rear and two side channels. Now, one of the questions I get all the time about the rear effects or surround channels is how high do they need to be.

My rule of thumb is that they should be a couple of feet at minimum above your seated ear height. So, if you have a low couch, as long as they are a couple of feet above where your ears would normally be when you're sitting, that's going to be great. Now, on the opposite end, you don't want to cram them up right against the ceiling unless you have a specially designed wedge-shaped speaker that's being used for those surround channels and some of those are designed to go right up near the ceiling.

But, in most cases, with our quad pole models, for instance, at least a foot from the top of the speaker to the ceiling is a good rule of thumb. Now, where should you place them? Well, in a 5.1 system where you only have two surround channels, it doesn't matter too much whether or not they're on the back wall, on either side of your listening area, or on the side wall.

If they are on the side wall, ideally, they're going to be slightly behind your listening position. You don't really want them, you know, right firing directly into where your seated listening position is. It's great if they can be behind you a little bit. It gives a more immersive effect and helps the speakers, those surround channels disappear more.

Now, if you have a 7.1 configuration and you have an additional two side channels, I always recommend that those side channels should be slightly forward or in front of the main listening area. This contradicts some things that I've read, but I found that if you have them slightly ahead of your seated listening position and then you've got your rear effects channels somewhere behind you, you get a nice immersive sound field all the way around from starting in front of your listening position all the way around behind you.

Now, let's address the elephant in the room. I warned you here. Now, Dolby will tell you that you can't have anything other than a forward-firing, directional radiating speaker for the surround channels. Where this got very, very confusing was in the early days of Dolby Surround, Adobe Pro Logic, these speakers were matrixed, so they were derived from the stereo left/right channels.

They were not fully discreet. What that meant was that you wanted a speaker that kind of hit itself good and when we came out with the quad pole models, that was ideal because there's nothing that necessarily fires directly at you. They radiate in a hemisphere when placed on a wall.

And there were some bipole models, there were some dipole models and actually, when the THX specification came out, in many cases, they said you want a dipole or a speaker that's switchable between a dipole and a bipole.

And some speakers in those years that manufacturers were developing had a forward radiating section so you'd have a woofer and tweeter on the front of the speaker and then they'd be flanked with two full-range or other driver arrays on angled sections that you could not only switch between being in phase, bipolar, or out of phase, dipolar, you also had a way that you could adjust the level.

This got very, very complex. So, this was in the day when THX was telling all the custom installers, you know, "Go knock on doors, make some money because nobody's going to be able to figure it out other than you professional guys." Once we got to Dolby Digital and now Dolby Atmos, Dolby has stated, "No, no, no, you don't want a dipole, a bipole, a quad pole, you don't want any of that, you want a conventional directional loudspeaker for the rear and side surround channels."

Now, I have a little bit of a beef with that because I've always found that when you use directional channels for the surround channels that you can locate the speakers too easily. And I hate that. When you have a nice surround effect, let's say that, you know, the movie you're watching is in a desert or in an environment where there's birds and crickets and things, you want to feel immersed in that environment.

I don't want to be able to go, "Oh, I can hear what's coming out of the, you know, the right surround channel or the left surround channel." I just want a nice enveloping, engrossing sound field so I can feel and imagine myself in that environment. And I find that when you use a directional loudspeaker in that application, it doesn't work so well.

Yes, with perfect Atmos encoded material, the effect can be better if you've got directional speakers all way around. But, my experience is that if the Atmos channels are directional, whether you're using in-ceiling or angled channels, you know, firing down at the listening position for your two or four additional Atmos effect channels, as long as you do that, I found it doesn't really matter what those rear or side speakers consist of.

I actually find that a mix with our quad pole QS series speakers and directional speakers for the Atmos channels work's really, really well and sound's great. So, one more thing that I'm going to address, which echoes exactly what I said, in the center channel video is back in the day of Dolby Surround Adobe Pro Logic, there was no bass information being steered to those surround channels, or at least not significant low-frequency information.

So, people got used to, you know, you have a little small satellite speaker or a little surround speaker on in the back, the subwoofer takes care of everything else. We're all good. Well, that changed with Dolby Digital, and now with Dolby Atmos that the rear and side effects channels can have full frequency range.

They can have real bass output. Now, I had some people comment on the center channel video, "Yeah, but even if I have a small center channel, as long as I tell my receiver or processor that, all that information is going to the subwoofer. Yes, I agree 100%.

The problem is that you can get into a situation where your center channel or in this case, the rear effects channels don't have significant bass output below a couple of hundred Hertz. Most subwoofers aren't going to go up that high and you end up with a gap. I also find that having multiple channels, the side surrounds and the rear surround effects channels with more bass capability of their own, even if the subwoofer is still going to take away, you know, you've set it so everything below 80 Hertz goes to the subwoofer, which is a typical setting, I've still found that if you step up to a surround speaker that can go down to, let's say 60 Hertz, like our, you know, our QS10 model, we'll get down there and lower, that you get a warmer, fuller sound with those effects.

So, you know, everybody, every customer of ours that had a QS4 or a QS8 like this and upgraded to the QS10 when we introduced it, were amazed. They said, "I didn't think it would make any difference."

And they went, "Wow, that extra bass output, that's a game-changer." So, you know, whether it's one of our bigger rear speakers or in other companies, it's just something to look at. Especially if you're, you know, if your system, your setup is 15 or 20 years old now, you might consider if you're looking at an upgrade to go with bigger side and rear surrounds.

And personally, I would do that before investing in the Atmos channels. Again, Dolby's not going to be happy with me for saying that. It's only my opinion and I find that those channels are more important on all of the content you're going to have other than, you know, those specific Atmos encoded videos and music, which it's building up, but it's not a big library yet.

So, I hope you can use some of those tips. You know, check out going with a larger speaker. Obviously, one thing I didn't mention, if you've still got a 5.1 system and your receiver is capable of 7.1, get some side channels, they really are going to make a big difference.

Are there other placement questions you have? Did you try any of these tricks and if so did it make a difference for you? Let me know in the comments below.

That's Tip #1. If you have a multichannel home theater system and you don't currently have a subwoofer, think about adding one. It really will handle the very, very bottom octaves better than pretty much any...even the largest floor-standing speaker on the market. So if you don't have one, add one.

If you're going to add a subwoofer or you currently have a subwoofer, is it suited to your room size? Is it suited to the rest of the speakers, particularly your main front left and right speakers? And what I mean by that is that an underpowered subwoofer for a very, very large room, or meted with very, very large floor-standing speakers, it's not going to perform the way that you want.

If you've got a pair of floor-standing speakers with dual 8-inch woofers, and you've got an amplifier that's 500 watts per channel, you shouldn't have a little 8-inch subwoofer with 100 watts in it. It's just not going to complement the rest of the system. A good rule of thumb is that whatever your amplifier power is upfront on the front left and right speakers, you should have in that same ballpark in your subwoofer's built-in amplifier.

And as for room size, it's going to vary depending on different manufacturers of subwoofers and what the output is capable. So call them, ask them, give them your room dimensions. We're happy to take calls at any time, and pretty much any good manufacturer customer service is happy to answer that question and recommend a suitable subwoofer for you.

But what if you already have a subwoofer? Lots of people are confused by subwoofers because they have inputs, they have, many times, lots and lots of controls, but there's a few basic things that you can check. Number one, if you're using a subwoofer output on a home theater receiver or processor, make sure that the subwoofer settings are suitable for your main speakers.

What do I mean by that? Well, even if you've used the automatic setup to tune the system, go in and manually check to see what the levels are set at. You don't want your main speakers at 0 or +1 dB on the trim setting and then the subwoofer at -6 or +8.

In that case, you can adjust the manual level control on the subwoofer to try and get those levels around the 0 dB trim. That's what you want. Otherwise, there can be cases where you're overdriving or underdriving the input signal to the subwoofer. The next thing is that if you're using the bass management, the filters and the roll-off settings in a home theater receiver or processor, which is typical when you use a sub output, make sure that if you're subwoofer has what's called an LFE input, an RCA jack that's labeled LFE, use that.

If it has a single jack or a jack labeled mono, use that. And then finally, if there's a frequency control, or a turnover control, as it's sometimes called, or crossover control, make sure that you have it set to the highest frequency. For more information on this, check out my article What Subwoofer Input Should You Use?

You don't want to have a filter built into the subwoofer electronics interfering with the one that the subwoofer output from the receiver and then adding up in sometimes very strange ways. So if you're using the sub out on a home theater receiver or processor, make sure that your frequency control is set to the highest position.

Now, placement. People tend to put subwoofers in the corner where they're out of the way. But if the performance of your bass seems too boomy or too thumpy, and it's overpowering everything else, try pulling the subwoofer out from the corner.

Even if it can just go half a foot to a foot, you might be amazed at how that will change the bass response that you hear at your listening position. The opposite of that is that if you don't have enough weight, enough thump, enough bass weight in the room, try pushing the subwoofer a little bit further into the corner, or if it's not anywhere near a corner, move it a little bit closer to a corner.

That's going to load up the room better at low frequencies and can give you more output, and it costs nothing to do that.

Those are just a few simple things, whether you have a subwoofer or you're looking for one, you can check out and try on your own. Read my related post Subwoofer Set Up: Where to Begin for more tips. You'll probably find in some cases, there's going to be people out there going, "Ah, I don't have it in the right input," or, "I never thought what to do with that frequency control."

So try those tips out. Let us know in the comments below what you found. And if you have any of your own subwoofer tips, you know, share them with the rest of our audience.

In our earlier post about speakers for tv hacks video and want to see more of those tips and tricks. So the front main speakers of any home theater system, the left, center and right speakers are pretty much the foundation of the system.

Yes, the rear surround or side channels or Atmos effects channels are all very important as well. But the bulk of the sound that comes on from any movie soundtrack is going to be over those front three speaker channels. So they are the most critical, the most important.

I mentioned in the last video on center channels that often we tuck small center channels on to a little stand below our display, tuck them in somewhere so they're unobtrusive, but this is really bad for sound. And often the left and right speakers, particularly if they're bookshelf speakers will be actually sitting in a cabinet, on a cabinet or in a bookshelf.

Many times people don't realize that if they bury the speakers behind the plane, the front surface of a cabinet or a bookshelf or frankly any opening, any obstruction, that's really going to reduce the potential performance of your front speakers, any speaker for that matter.

So, have a look. If you've got a speaker like a bookshelf speaker that's in a cabinet or on a bookshelf, check to make sure that the front plane of the speaker is at least flush with the front of the cabinet or the front of the surface that the speaker is sitting on.

Even if it's only an inch or two set back, that's going to have a massive, a massive detriment on how smooth the frequency response from the speaker is. You're going to cause a bunch of small reflections that are now going to impact the performance. And when it comes to the center channel, that's directly going to screw up the quality of the dialogue and possibly make it less easy to understand and hear.

So, simple tip, if you've got bookshelf speakers or a center channel sitting on something in a cabinet, or on a bookshelf, make sure you pull them forward. And if you haven't, do that and listen to a track that you've recently listened to, or do a direct AB before you pull the speakers forward into a better position, listen to something very carefully and critically, pull the speakers forward so that they're flush with the plane of the cabinet or the shelf and listen to the track again.

I guarantee you you will be amazed by the results of that simple little thing that many people don't understand. So thank you for watching.

Of course, it has to be. Well, I do get a lot of customers calling and asking me, "Why do none of these Bluetooth speakers sound very good?" There's no bass from them and they don't play very loud. And I'm just not really happy, I mean, I don't expect it to sound like my big full home stereo system. But is there something that plays bass? Is there something that's got quality?'"

And the question I'll ask back of them is, "What kind of Bluetooth speaker are looking at or Wi-Fi speaker?" And they'll give me some model number of some XYZ company thing. And I'll look it up and it'll be a tiny little thing the size of an old school clock radio maybe or even worse something that is in the shape of a little beer or a pop can.

Frankly, you're never going to get good performance out of that. Customers ask "Why?"

Well, we unfortunately can't cheat the laws of physics and there are a couple of things required if you want bass performance and you want output. So, you want it to be able to play very loud.

Basically, you need one of two things and it's better if you have both things. You need size, so you need volume, you need an air volume, cabinet volume that's big enough to support the bass frequencies and load the woofer drivers properly. And you also need power. You want it to play loud, you need amplifier power. Now, there's a lot of very detailed acoustic and electronic things that we have to worry about as loudspeaker engineers and electronics designers. But basically, the bigger the cabinet, the more bass that you're going to get up to a limit, but it's not something that's tiny and can fit in the palm of your hand.

And you also need power.

I've looked at some of these small, little Bluetooth speakers, some of which are very popular. And they may be okay at small levels if you've got them sitting on a table on your patio and you're listening real close up. They may be okay, but they don't provide any bass.

And when you look at the actual manufacturer specifications, often they'll not even tell you how much amplifier power is built into that speaker. Why? Because they either assume that nobody needs to know or wants to know, or they're ashamed to admit that that little speaker has only got one watt of power.

Now, one watt can generate a reasonable amount of sound if you have a fairly efficient speaker and it's in a big volume, a big cabinet, particularly at bass frequencies. So, the moral of the story, unfortunately, is that if you want bass and you want power output, i.e., you want to be able to have a party with your Bluetooth or wireless speaker. It needs to be something like this, our AxiomAir Force, which, yes is fairly big, much bigger than any of these little breadbox or clock radio-size Bluetooth speakers. But it also has a complement of speaker units, two 6 1/2-inch woofers, two 1-inch tweeters, that's common in many good quality bookshelf speakers, and there's a 150-watt amplifier in here. And that's more power than many home audio systems have.

So, if you want the performance, you need the amplifier power, you need something that's of big enough size to support bass. If you're just going to look at an inexpensive, very small, compact thing, you're never going to get that performance out of it. Unfortunately, it's just physics.

I wanted today to talk about center channels, a speaker in the home theater system that often doesn't get a lot of respect. And what do I mean by that? Well, I'll give you a story that happened a couple of days ago with a customer who called me and was looking for advice on upgrading his home theater system.

He has our main speakers for his front left and rights, and they're big tower speakers, one of our biggest models. He has another company center channel that he wants to upgrade because he's not happy with the quality of dialog or the balance with his main front left and right speakers.

So, when he told me what main speakers he was using, I recommended one of our larger center channels. And right away he went, "Oh, no, no, no, I want something about the same size as what I have now, just from you." Well, that would be our smallest center channel, this, the VP 100. And you hear this time and time again, the poor center channel needs to be small because it needs to be in the center of the room near the display.

Often it's tucked into a shelf on an equipment rack that's below a television, sometimes right near the floor. I've even seen some...I mean, it's horrible in terms of performance. So, why should we worry about the lonely little center channel? Well, back in the early days of home theater when we had Dolby Surround and then Dolby ProLogic, there wasn't a heck of a lot of information that came out of the center channel, it was mainly dialog and dialog that was centered in the action that was on the screen.

There also was not much in the way of low-frequency information. So a lot of people that built up a home theater system, let's say, 20 years ago, are still applying that kind of logic to what the center channel needs to be in the system because they're thinking about these old formats and being able to get away with a small center channel.

Today that's not the case, hasn't been the case for many years. When Dolby Digital appeared, we now had discrete channels, so they were not, you know, derived from a stereo signal, which the earlier Surround and ProLogic formats were.

We now had discrete channels, and all the channels, including the center channel and the surrounds, had the capability of low-frequency information. They could be full range. So, if you want the best performance from a home theater system, you now need a center channel that has the same kind of capability for full range as your main speakers.

So, one of the other things that I hear, and I mentioned it earlier, people complain about is, "I can't hear the dialog in movies very well," or, "I can't hear what's going on in the TV show." You know, "My center channel just doesn't seem to be producing what I think that it should so that I have clear dialog." Now, unfortunately, sometimes that's the fault of the production of the movie or the TV show.

Often, not the proper amount of information is mixed to the center channel. But often the problem is due to, again, using a center channel that's completely underpowered and doesn't have enough bandwidth to match the rest of your system. Now, before you go out and say, "Well, okay, you're now telling me I have to spend, you know, a ton of money on a bigger center channel that I don't have space for," there are a few things that you can try and you should try with whatever your current system is.

If you're not happy with the performance, here are two things that you should really try. First thing, go into the manual level settings or the speaker setup settings in your receiver or your home theater processor. Go in there, and even if you've used the auto-setup or you're using Odyssey or some correction system, take the level trim of the center channel and bump it up by, let's say, 2db to start with.

Go back and listen to some movies or watch some TV shows if you've DVR-ed them that you were having trouble understanding. A db or two higher level out of your current center channel may help with that, may help with the intelligibility of the dialog. That's totally free, all you have to do is probably dig out that massive manual or go online to find out how to access those settings if you don't remember for your receiver.

The other thing that you can try, particularly if you feel that what's coming out of the center channel is thin, it's probably because your main speakers are full range or you have a subwoofer in the system that's contributing a lot to the rest of the system but not so much with the center channel. Even though you may have your center set to small and that information should be coming out of the subwoofer, there is still something to be said about that mid-bass information that is maybe slightly too high a frequency for the subwoofer to be carrying.

What you can do in that case is actually try turning the center channel off in your receiver or processor. I know this sounds completely crazy, "So you're telling me to get better center channel performance, turn it off?" Yes. And again, in the early days of surround, there was something called a phantom center channel.

People who hadn't actually bought a center channel yet and still wanted to listen to their new surround sound system could go into their receiver or processor and tell it that they don't have a center channel. What will happen then is that the receiver will send that information equally to the left and right front main channels and give you the center channel information. Now an interesting thing if you go and do this, because even the most modern processors and receivers will let you say you have no center channel, if you try that, what's interesting is that now if you have a small center channel and big full-range main speakers, by turning off the center, now you may experience a much fuller sound from that center channel dialog information and the special effects that normally come out of that center channel because they're being reproduced by a much bigger full-range speaker.

Now, if you...you know, it's only yourself or maybe yourself and your spouse or partner that, you know, has one small listening area, you may actually find that you like that phantom center channel configuration. And if you do, fine, I'm not going to tell you to buy a center channel, even though it seems counterproductive, we're a loudspeaker company.

But if you like it, hey, it's perfectly fine. Now, where it becomes problematic is if you have a large seating area and you tend to have a big family gathered around, you know, watching TV or movies. That phantom center is probably not going to give you a nice solidly defined image that sounds like it's coming from the television everywhere in the room.

And in that case, unfortunately, the only thing that you can really do is get a bigger center channel, one that's more matched to your main speakers and the rest of your system. So the rule of thumb that I always recommend is if you have a pair of floor-standing left, right front speakers that are your main speakers, and let's say they have two, 6.5-inch woofers, and they're a ported speaker, well, I would look for a center channel that has two 6.5-inch woofers and it's ported.

And look at the specifications, see if the low-frequency extension is similar between your main speakers and the center channel that you're considering. Now, the other thing to look at is if your main speakers are a three-way system, so you have a tweeter mid or end woofer or multiples of any of those things, look for a three-way center channel.

It's probably going to match better in terms of total balance to your main speakers. And the final thing that I will mention is it's always a good idea to buy a center channel from the same manufacturer as your front main speakers. And if the manufacturer that your front main speakers are from has multiple product lines, some of the bigger speaker companies have a whole series of different lines, try and buy a center channel from the same line within that brand that match your front left and right speakers.

It's a better guarantee that there's going to be a more seamless match between the dialog and the character of the rest of the system. So don't be shy, if you can, make room for a bigger center channel if you have large floor standing speakers, you're really going to love it. And hey, check out the phantom center, you may love that too.

So, should you get a soundbar, or conventional speakers? Basically, they will accomplish exactly the same thing. So, it’s really a matter of aesthetics, convenience, and how you want the system to perform.

Whether you have a pair of stereo speakers or an entire surround sound system, if you have the luxury that you’re not worried about having to have speakers out into the room and you have the space for it, that’s always going to give you the best performance. There’s no way around it. No amount of signal processing trickery is going to fake a good proper multi-channel surround system with speakers that are placed ideally for performance.

But there’s also complexity with those systems. You need a separate receiver or a separate processor and power amplifier to connect everything up and to power the speakers. Now, there are some cases where you can get active speakers or wireless speakers that have built-in amplifiers. But typically, those will only be for a stereo system, not for a full multi-channel surround system.

Soundbar or Speakers: The Middle Ground

There is a middle ground if you don’t have the space to place the speakers out into the room, but you want better performance than a soundbar is going to provide, then you can look at on-wall or in-wall speakers that, again, can be placed spaced apart, so that you’ll get a better sense of space in image.

The Open Bar + Subwoofer = Great Option For Small Spaces

The boundary effect, which loads a subwoofer, you can think of it as amplifying the low frequencies that a subwoofer will produce. Now, it'll happen with any speaker that produces low-frequency information or bass information, but subwoofers, because they're dedicated only to those low frequencies, it's usually what we talk about in terms of corner loading. You're not going to normally put your full-range speakers in the corner. It's not going to sound very good.

Watch A Video on Corner Loading Subs

So what is the boundary doing? How is it causing this amplification? Well, the number of boundaries, the number of large surfaces that you have around something that's radiating low frequencies will reinforce that. For example, a single boundary: if you had a subwoofer placed in the middle of your room, the floor is the boundary.

If you then moved it against the back wall in the center of the room, you now are loading with two boundaries, the back wall, and the floor. Obviously, if we extrapolate from that and go to the corner, now you have a point in the room where three boundaries are all impacting the low-frequency output of your subwoofer or amplifying it if you want to think of it that way. So the question becomes, well, why don't we always put subwoofers in the corner of the room?

Well, rooms are tricky things with low frequencies. You have something called standing waves that'll reinforce some bass notes and will actually reduce bass notes in different ranges, so you end up getting a frequency response curve that looks like hills and valleys. There's nothing you can do about this other than sophisticated room treatment.

You can do some equalization, but that's not always going to work particularly if you want to fill in a hole in the bass frequency response. By putting a subwoofer in a corner or corner loading it, you're going to have much more interaction with the room because again, you have three boundaries all in play at the same time, amplifying the low-frequency output of your subwoofer.

In some rooms, corner loading a subwoofer will actually give you more output. It might even give you smoother output. Typically, though, I would only recommend it for smaller subwoofers where you wanna boost the output or amplify it a little bit because typically, that corner loading is going to give you more uneven bass than even if you pull the subwoofer out two or three feet from that corner.

The closer you get to the boundaries, the more of this loading effect that you're going to get. So it's a tricky thing. Again, low frequencies are the biggest issues in typical small rooms, like we have our audio or our home theater systems, but corner loading can help you out in some situations, particularly if you have maybe not enough subwoofer for the room that you're trying to integrate the system in. So there's no harm in trying it out. You may actually like that bass emphasis, and that's all corner loading is going to give you.

Watch a Video on the Best Songs To Test Speakers With

You shouldn’t necessarily listen to just these sorts of albums. I’m sure many of you will watch this video and say, “Oh, that’s not the kind of music I listen to.” That’s a very, very important point. At the end of the day, it’s your speakers, your system, your room, and your music. So, you have to be happy with the performance of the types of music you listen to.

I’ve created a Spotify playlist so you can actually check out some of these things with your own system for yourself and see what you’re hearing and playing with things like placement and toe-in and see they how they affect the performance of these recordings.

Speaker Set Up Test Discs

Let’s start with a test disc, or test CD: something that’s got test tones, either sine tones, or warble tones. The one in the Spotify playlist that we’ve linked is very good because it has warble tones at different frequencies. Why is this useful? Well, if you’re going to listen for improvement in changing the location of your speakers, and how it interacts with the bass modes and nodes in your room, having a way that you can precisely hear at specifically frequencies how that’s being impacted is important.

Even better, with distinct test tones at different low-frequency points, along with a sound level meter, if you happen to have one, means that you going to actually draft with plot what the bass measurement looks like in your room. Now, that’s really important because sometimes bass is very tricky, because depending on your listening position, depending on the specific construction or your room, what you have in the room, whether it’s carpeted, etc. can all impact this. So a test disc and test tones are very, very helpful for set up, particularly looking at what the bass is doing.

Checking for Boominess

The next recording is Holly Cole’s, “Temptation.” If you’re not familiar with her, she’s a Canadian vocalist. Her albums all very well known for being extremely well recorded. “Temptation” is very interesting because it’s minimal backing, it’s piano bass, and drums, and sometimes percussion behind her voice. Her voice is in a fairly low range. So, if you’ve got too much boominess in the setup of your speakers go here right away with her vocals. The track “Temptation” is very minimal, with some percussion that’s almost like bongo drums with very, very low subterranean acoustic double bass. It’s a great, great test track. Every instrument should appear its own point in space, and clearly defined when you’ve got your setup right.

Checking for Reverb and Natural Sound

The next album, another Canadian artist, or Canadian band is Cowboy Junkies’ “The Trinity Session.” This is another famous recording in a number of respects. It was done in an old church in Toronto, Ontario, Canada, and all of the performers are positioned around a special omnidirectional microphone. And they’re actually in a very, very natural acoustic space. There’s a wide variety of different instrumentation on this album. And Margo Timmins’s vocals can sound thin and screechy if your system is not set up right. The intro track “Mining for Gold” is her a cappella with the natural noise and reverberation of the church that she’s singing in. It’s an incredible test for good imaging and I’ve been listening to this album and using it as a setup album pretty much since it came out in the ’80s.

Checking for Imaging

Another track again with a female vocalist (you’re going to see a theme) that I like to use is Joan Baez, “Farewell Angelina.” It’s her doing an album of Bob Dylan covers. It’s very well done. I like it, you know, musically, even more than the sonic quality. But again, it’s minimal instrumentation. Very, very well defined, and well recorded. Good bottom end. And again, you should be able to listen to a recording like this when your speakers are set up properly, and actually close your eyes and clearly tell where Joan Baez is, where the different instruments are, and they shouldn’t waver. You should have a natural acoustic perspective around each instrument if things are set up right.

Checking for Bass Balance

The next album is the classic Pink Floyd’s “Dark Side of the Moon.” Now it’s a pop recording, but of course, it was done in a time where everything was analog. Even the synthesizers used on this were analog. So, there’s a certain tone and warmth to the recording, whether you have an LP like this, or whether you have a compact disc, or even listen to it on streaming services. There are very, very complex, dense moments in this. If you know the beginning of “Time,” if you know “Money,” all of these tracks have ping-pong effects, but the acoustic is very natural. Everything should sound very nicely balanced with a good weighty, weighty bottom end. I mean, the bass is thunderous. This has been used as a test track in stereo stores since it came out in the early ’70s. So, it’s a very, very good track. Again, a lot of you are going to think, “Oh, it’s boomer music, I want something more modern.” Just listen to it, if you don’t like the music from the sound perspective, it’s very good helping setting up. If the heartbeats that start the beginning of the album sound too boomy and thumpy, change the position. They should be weighty and full, but well defined at the same time.

Check For Toe-In and Cymbal Reproduction

The next disc, a Jazz album, a famous one, “Time Out” by The Dave Brubeck Quartet, with the famous track, “Take Five” on it. Now, most people, if you start playing “Take Five,” they’ll know it immediately. Even if they can’t tell you what it is, it’s a famous track. What also is very, very well known about this album is the recording quality. It’s absolutely stunning. The symbols and the bass drum on this recording are so natural that it’s an incredibly tough test for any audio system. If you can reproduce it well, it sounds like you’re in a jazz club with these wonderful musicians. If everything is a little washed out, ill-defined or if tending to clump towards the center between the speakers, you don’t have your toe-in setup right. Try adjusting it until you get a wide space in perspective between the different instruments. It’s a great recording for that.

Check Your Speaker Placement

Now, turning to a classical piece. This is Carl Orff’s “Carmina Burana.” This recording is on Deutsche Grammophone. But there are many, many good recordings of this piece on Telarc, had a great one on CD that might be on streaming services. I couldn’t find it on Spotify. So this is the one that’s on the Spotify playlist, but it’s a very, very complex, heavily orchestrated piece of music, full symphony orchestra. There’s solo vocalists. There’s an entire mass choir. And this is a real good recording for putting on and seeing, does everything completely fall apart when it gets really loud and raucous or can you clearly still hear the different sections of the orchestra, the choir, the soloists all in their own individual space with weighty, nicely balanced bottom end. The double basses and cellos should not drown out everything else. If they do, check your speaker placement: pull them out from the walls a little bit to try and deaden the bass in your room. It’s a great recording.

Check Depth of Image

Now this next one, you’re probably not going to find on any streaming services. There was a small Swedish audio file label called Opus 3, I think they are actually still around, and they had a series of first LPs and then CD reissues that were all looking at different parts of listening. This one is the “Depth of Image.” I also have the original LP here, Test Record 1. Number two in the series was “Tambor”, which looks at the different sounds and structure of different instruments. These recordings, I think there were four or five in the series, are a little hard to find now, but you know what, if you’re really into tweaking the last percent or two to try and get your system at its utmost, track these down.

The “Depth of Image” album, in particular, is just incredible. There are tracks on here with complex pan pipes or pan flutes that bounce from the left the right channel, and they’re complex to reproduce tonally, but just as complex to get that imaging working well. So, I mean, these are torture tests. If I set up a system and I listen to this album and it sounds really, really good, and the soundstage on every track is excellent, the imaging well-defined, I’m done. I’m finished. I don’t have to tweak anymore. I’m going to just enjoy listening to my music.

Now, AC/DC’s “Back in Black.” Yeah, I’m sure some of you have been wondering, “Are you going to play any real music, some metal, some hard rock, you going to suggest anything like that?” Absolutely. AC/DC’s “Back in Black” believe it or not, was an incredibly well-recorded album, incredibly well-recorded. It’s dense, it’s thick, but it’s layered. The instruments all sound fantastic. And you know what, it’s an important album that you should listen to. I have copies on both CD and LP  and it’s on the Spotify playlist. Check it out. Everything should sound dense, but it shouldn’t sound all mashed together when your setup is right.

And then the final album that I’m going to mention is a modern one. It’s the latest Billie Eilish album. And I know there’s been a lot of talk in the audiophile community on music and audio forums about how the bass is really distorted on this album. Well, yeah, it is, but it was done for effect. It was done on purpose. But amongst that very, very heavy, dense, distorted sounding bass are some fantastic vocal synths, fantastic effects. It’s a heavily produced album. There’s a lot of studio trickery going on. But you know what? It actually is one of the best recordings from a top 40 artists in the last number of years that I would say is really, really well-recorded and very hard to reproduce because you have a lot of very dense heavy bass going on with Billie’s vocals at the same time. And again, they should be distinct, shouldn’t sound like a mishmash of things. And it’s really a great recording to check out. I’m sure many of you have listened to it and are going, “Wow, I didn’t even think that that could be something to help with my speaker setup,” but it’s really, really a great recording.

So, please give me some comments down below if you’d like. If you have albums or CDs or streaming cuts that you use for setup, share them below, not just for my benefit, but for everyone else who watches this video. It’s very interesting to see what people use for their speaker setup and their system setup. So please share that, check out the Spotify playlist. Like I said, most of what I’ve talked about is on that playlist so you can check the tracks out for yourselves. And, you know, if you’ve got problems if you listen to some of these tracks and go, “Geez, that sounds really this or really that and is that right?” Again, comment below, ask, I’ll make sure to keep watch of the comments and answer when I can.

See Our Full Speaker Set Up Playlist

Dolby Atmos and Brave

Although you can now enjoy the power of Dolby Amos in the comfort of your own home, the surround sound technology was first leveraged for the premiere of Pixar’s “Brave” at the Dolby Theater in Hollywood, California.

During the rest of 2012, the technology was part of a limited release that only included about 25 installations around the world. By 2013, that number got closer to 300. Within two years, it was up to 2,100 theaters.

Dolby Atmos in the Home

This powerful surround sound technology was eventually adapted for home theaters and released to the public in 2014. The first DVD to support this improvement in audio was Transformers: Age of Extinction.” Star Wars: Battlefront” was the first videogame to have this distinction.

The Main Features of Dolby Atmos Home Theaters

There are two features that make Dolby Atmos stand out from other home theater installations.

1. Moving Audio

   The first is what is known as “moving audio.” In simplest terms, this effect is similar to surround sound, except that you’ll feel as though the audio outputs are moving all around you during your film. This “3D” effect is meant to make you feel as though you are inside the movie with the action happening nearby.

   Up to 128 audio outputs can be played at the same time with Dolby Atmos. This gives an effect that is exactly like the kind you’d experience at most theaters.

2. The Helicopter Effect

   Another cool feature of Dolby Atmos is what’s known as the “helicopter effect.” One problem with traditional versions of surround sound is that they can’t possibly mimic the sound a helicopter makes when it’s above you (or any sound happening overhead, for the matter).

   While they may be able to reproduce the audio, generally, the speakers can’t make you feel as though the sound is coming from above.

   With Dolby Atmos, sound happens as individual entities, which are referred to as audio objects. This means helicopters and other noise producers onscreen are not restricted by channel assignments.

   This is pretty cool all by itself, but because you can place the audio overhead, it means that unique effects like the sound of a helicopter can now be enjoyed in 3D space. Dolby Amos is the first audio format to provide this type of cinematic experience.

Of course, you can also add overhead speakers to further the effect of this new sort of surround sound. Common installations for these purposes include:

• Ceiling Speakers
• Dolby Atmos Enabled Sound Bar
• Dolby Atmos Enabled Speakers

Even the speakers that you have standing on the floor are designed to aim sound up so it reflects off the ceiling and, again, produces the helicopter effect.

If you treasure home entertainment, it’s worth considering adding Dolby Atmos speakers to your setup. You’ll feel like you’re at the theater.

Note: The picture used for this post is courtesy of one of our customers, whose installation The Temple of BOOM can be found on our Wall'o'Fame. Got a picture of your own to share? We love seeing your creative installations!

Audiophile has a kind of a negative connotation in some respects. People think that they're just a bunch of obsessives that pick apart music and all those things. But, you know, I'm a huge music fan. That's why I love good quality audio. I don't love the equipment. If the equipment could disappear and I could still have the great sound, that would be fine. But we're not there yet: maybe sometime in the future.

So you're just starting out. One thing you should not do...please do not go on to X, Y, Z online high end or audiophile forums and say, "I don't know what I'm doing. I'm brand new here. Tell me what I should buy." The problem is with any passionate interest and, music and good quality sound, people are passionate about that. Anytime you have somebody that's passionate about that, they're also going to be usually quite opinionated and you'll be bombarded with a hundred different recommendations for equipment and things you know nothing about, you have never heard of and then the arguments will start. So I would avoid that completely just for a while, just until you get your first system set up and have some experience with it.

Well, how are you going to find out what you need? If you don't go online and talk to people, what are you going to buy? Ask yourself the question, "When did you get interested in audio? Why are you even thinking that you want to become an audiophile or you're interested in the world of high-end or high-quality audio?" I bet that you can trace that back to a friend or relative and acquaintance that had a nice system. Might've been years ago, might have been recently. And that's how you got the idea that you wanted to, you know, get into this hobby. Go to them going. Go and ask them. Ask around amongst your group of friends, "Hey, do you know anybody that's got a cool audio system?" And go and talk to them. Many cases, they'll invite you over and let you hear their system and you can experience what these systems sound like in a person's home, which is actually the best way to experience a good quality audio system.

So that's the first thing that I would avoid. The next thing I would avoid is, when you're building a brand new system from scratch, anything that's not a major component. So you've decided that you want to get into listening to vinyl, or you have a vinyl collection that you haven't listened to for years and it was on a bad system. You want a turntable and a pair of speakers and you want good quality. So you're going to need a turntable, an integrated amplifier or receiver of some sort, and a pair of speakers. Don't worry about cables. Don't worry about stands. Don't worry about feet. Don't worry about power conditioners. Stay away from all of that stuff.

I have no issue if you are one of the camp that feels that cables make a huge difference, go nuts. But for somebody starting out, your system will work perfectly with the "junky cables" that come with the equipment. So remember that. The system will work. Get used to it. Don't go out and take half of your budget and spend it on the accessories and the cables and things right out of the gate. Divide your budget up into the best quality components that you can afford. Start there. Live with it. Listen to it.

Now, another thing that I would really highly suggest that you do is look to see whether or not, if you're in a larger metropolitan area, there isn't an audiophile group meeting, you know, once a month or some places in parts of California, in New York City, Boston actually have audiophile societies. Now, that's a great way to meet people with a similar interest in what you're interested in. And, again, you're probably going to get invited over, you're going to get to hear a bunch of great systems and that's a wonderful, wonderful way to get into the hobby.

Another thing is to check whether or not there's any audio shows or audio expos going on in your area. They're all over the U.S. there's a number of them in Canada and there's a number of them in pretty much every country in Europe. So go and check one of those out. Why? Because it's a great way, under no pressure from a salesman or a dealer, to go and experience and listen to a bunch of equipment. Go look at it, touch it, check it out, talk to the factory and company reps that are there and ask your questions. It's a really, really good way to get an idea of, you know, the extreme range of prices, sizes, all of those things. And, you know what? You might bump into somebody who has a similar interest and is just starting out. So, you know, it's a great, great thing to do.

One other item that I would tend to avoid is worrying about somebody else telling you what you should or should not do when it's your first system. And this is why talking to somebody who is an audiophile, going to one of these shows is important because, you know, somebody is going to tell you you need a tube amplifier, somebody is going to say, "Oh, don't waste your time on a turntable. Get a good CD player. Or forget all of that and just get a streaming player." Well, that's fine. But, you know, think about how do you listen to music now? Do you have a collection? Do you have CDs? Do you have LPs? Are you strictly streaming on Spotify? That's going to dictate what kind of source components you need.

And, again, when you're starting off, I would keep it simple. Pick the one main source component that you have the most music on. Say it's CDs, buy a good CD player, a good integrated amplifier, a good pair of speakers. Start there. You can always add a streaming player. You can always add the turntable later on if you want to. But maximize that budget when you're starting out and I guarantee it's going to be fun. Later on, if you want to crawl into the shark-infested waters of the, you know, internet audio forums, go ahead. But make sure you have your flame-retardant suit on.

Today's AV receivers or AVRs have a come a long way from the stereo era; in fact, as multi-channel formats keep evolving, simple stereo receivers have become a rarity. For those of us who still recall the days when 2 channels was all that was available, the move to the latest Atmos-enabled 11.2 AV receivers is something of a mixed blessing. Multi-channel surround can sound wonderful, of course, but choosing and operating a 5.2, 7.2, 9.2 or 11.2(!)-channel AV receiver is not nearly as straightforward as we might hope.

Command Central

An AVR serves as the command center for a multi-channel AV system, performing audio-video routing, switching, surround format decoding, and amplification. For many years Dolby Digital 5.1 surround sound has been the standard for HDTV broadcasts. HD sources offer anything from Dolby Digital all the way to the latest Atmos encoding format. This includes network streaming players, Smart TV Apps, and Blu-ray players, so you will want an AVR that has the ability to decode the latest and greatest.

Many AV receivers are also able to act as network streaming hubs, prodiving access to YouTube, Netflix, and Amazon Prime Video, along with the abilty to play audio from your phone or tablet over AirPlay, Bluetooth, or Google Cast.

Power Output

It’s a receiver’s first duty to amplify the weak incoming audio signals to a level where they’ll drive loudspeakers to clean, reasonably high volume levels in most typical living rooms or home theaters without audible distortion (the latter produces harsh, edgy sound). The first thing to look for is the receiver’s rated per-channel output power into an 8-ohm load. (Most domestic speakers are either 8 ohms or 6 ohms impedance, which are essentially identical for purposes of power output).

The biggest problem with the per-channel rating is that it is frequently only one channel driven, so that every added channel will reduce the per-channel output power e.g., “100 watts per channel” is actually 50 watts per channel with 2 channels driven and 14 watts per channel with 7 channels driven. This recent habit of taking the 100 watts per channel and multiplying it by 7 (“100 watts x 7”) to get the so-called “total power” is complete nonsense.

The laws regarding AV receiver power output specifications are ridiculously lenient, so much so that if the aforementioned rating standards were applied to Axiom’s ADA1500-8 multi-channel power amplifier, we could state its power output as “1300 watts x 8” or as having a “total power output” of 10,400 watts! How did we arrive at this? The ADA1500-8 will produce 1,300 watts into one channel at 2 ohms, with one channel driven, so 1,300 x 8 channels gets you the absurd 10,400-watt “output.”

Keeping it Real

Axiom M80 Floorstanding Speakers in Maple Natural Wood Finish

The only method to determine how much power an AV receiver truly generates is to separately measure the total watts produced by each channel, or to drive all channels simultaneously and measure the output of each. Some brands don’t weather that sort of stress and immediately shut down. Others manage it quite well, which points to a good, robust power supply section in the receiver. In a perfect world, every manufacturer would state the power output of AV receivers with “all channels driven,” either five, seven, nine, or eleven, into 8-ohm loads, over the full musical range. The power output will often be significantly less than with one or two channels driven, but if you find all channels driven spec or measurement, take it as a positive sign of robust amplifier design. If you’re thinking about getting a pair of 4-ohm rated speakers like Axiom’s M80s for your front main channels, check with the manufacturer to see if their AVRs can drive 4-ohm loads. Some brands will not drive 4-ohm speakers without overheating or shutting down. Others, with excellent power supply capacity, have no trouble with 4-ohm impedances.

Look for the continuous power output with two channels driven into an 8-ohm load, over the full audio range of 20 Hz to 20 kHz (more often you’ll see the power output rated at a single frequency, 1 kHz) with total harmonic distortion (THD) of less than 1%, ideally 0.7% or lower. Distortion at that level is generally conceded to be inaudible with musical programming or soundtracks. Keep a close eye on the THD (distortion) ratings. Some manufacturers play fast and loose with power ratings, even specifying some packaged home theater in a box (HTIB) electronics at distortion levels as high as 10%, which will not only be audible but downright nasty sounding.

How Much Power Is Enough?

To cover all but very large rooms and extremely high-volume playback, most people will be quite happy with AV receivers rated at between 75 and 125 watts per channel, with two channels driven. Although many AV receivers will deliver far less than that when all channels are driven simultaneously, it’s not a severe drawback. Even with the most raucous movie soundtracks, it would be extremely rare to ever find an AV receiver having to produce simultaneous output of 70 watts or 100 watts into each of its 5 to 11 channels. Typically, the surround channels demand far less power output (a few watts) than do the main left, center, and right channels, which carry the bulk of the acoustical output demands.

Don’t obsess over small differences in power output. It takes a doubling of power to make any significant difference in playback volume. Thus, if you had a receiver with 50 watts per channel, you’d need to go to a model with 100 watts per channel to get a 3-dB increase in loudness, a difference that is just “slightly louder.” Differences of 10, 20, or 30 watts per channel are just not significant in receivers rated in the 100 watt-per-channel range. (For more information on this topic, read this article on the nature of power.)

Inputs and Outputs

One of the most important functions provided by an AV receiver is source selection, allowing you to choose which components (Network streaming boxes (Roku, Apple TV, Chrome Cast), DVD, Blu-ray, cable or satellite TV, etc.) to listen to and watch, so keep in mind how many audio/video sources you may want to connect now, and in the future. Pay particular attention to the number of HDMI inputs available, as the number can be too limited with entry level AVRs.

It's also imporant to pay close attention to the video capability of an AVR's HDMI inputs and outputs to make sure they are able to provide the required signals to your HDTV. There's no point in purchasing the latest and greatest 3D or 4k HDTV only to purchase a receiver that's incapable of passing those signals.

If you anticipate getting a separate power amplifier with much greater power output in the future, then make sure the AV receiver has “pre-outs” (preamplifier output jacks) for all channels.

Multi-channel Surround Sound Decoding

Your AV receiver will do much of the work of “decoding” the various new and older surround sound formats. There are now a multitude of surround formats, Dolby Digital 5.1 being the standard of HDTV broadcasts and standard DVDs. Other formats include Dolby Atmos, Dolby Digital EX, Dolby Digital Plus, Dolby TrueHD, DTS, DTS-ES, DTS-HD, DTS-HD Master Audio, Dolby Pro Logic II, and Dolby Pro Logic II x. Thankfully modern AVRs have the capability to decode these formats on the fly, auto sensing which is in use and decoding accordingly.

Today even some entry-level AV receivers are capable of decoding the newest Dolby Atmos format, and more and more source material (both music and movies) is becoming available, so it's a good idea to look into an Atmos-capable AVR, even if you don't plan on immediately building an Atmos speaker system.

On-screen Display or App?

Most AV receivers have easy to read on-screen displays so you can navigate the receiver’s settings during setup and calibration. Many models also have an available control App that can not only be used for setting up your AVR, but also give you the ability to use your phone or tablet as a remote control.

Auto-Setup and Calibration

Even inexpensive AV receivers have some type of auto-setup mode, with most including a supplied microphone and auto-calibration/equalization setting (Audyssey is very common) that claims to adjust the frequency response of the system’s speakers to match the room’s characteristics.

While the auto-setup modes are initially useful for first-timers, they are still prone to error, sometimes setting speakers that are small to “Large” and making errors in speaker level settings of 4 dB or more. You should still do a manual check using a sound-level meter or your ears along with the built-in test tones.

Unless you have really poor speakers, I recommend you turn off the auto-EQ circuits. They may help smooth out the non-linear spikey frequency response of poorly designed speakers, but with really smooth linear speakers like Axioms, they often degrade sound quality.

Check the Remote Control

Remote control design is all over the map, and you often find a really desirable AV receiver with an annoying remote control that has illegible markings, lacks backlighting or uses tiny buttons all the same size. One can get used to almost any remote, but remotes with larger, different-shaped buttons, backlighting, and easily readable markings go a long way to making a remote control easy to use. If you don't want another remote control that will just get lost in the cracks of your couch cushions, an AVR that offers a remote control App for your phone or tablet might be just the ticket!

Video Processing

Your HDTV will automatically perform its own video processing, converting incoming video signals in order that they conform to your set’s specific fixed-pixel array. AV receivers also contain video processors that will perform similar functions. Most modern HDTVs have auto input sensing so that you won't need to worry about selecting the correct video output format (720p, 1080i, 1080p, 4k) from your source components. It's one of the huge benefits of HDMI connections as components are now able to talk to one another, greatly simplifying the setup of your home theater system.

That’s it. For more detailed questions, send us an email or post your question to our Axiom forums, accessible on the Axiom home page, where many Axiom enthusiasts will help set you straight.

Now, unfortunately, to do that you need a new set of speakers. You need a set of wireless speakers. Even though a wireless speaker gets rid of the speaker cable and the connection to the amplifier, you then need to move the amplifier inside the speaker. So in addition to having a wireless component, it has to have its own amplification, its own power built in. But you don’t have to replace your whole system.

Watch My Video On How To Make Speakers Wireless

If you have a system with a receiver or amplifier, a home theater system with a good home theater system that you enjoy, then you can add a simple transmitter box that you take a RCA output from your receiver, and then it will then send the signal wirelessly to the speaker so you can place them without having to worry about running speaker cables.

The other version of that question about making my wired speakers or my wired system wireless has to do with all of the great music services and functions that we have available and are used to every day, using on our phones or on our computers. You may have a streaming music service from Amazon or Spotify or TIDAL. Maybe if you have an Apple device, you may be used to being able to Airplay anything, like a YouTube video to another component. And maybe you want to have all of those functions integrated into your existing audio or home theater system.

Many people think that “Oh, I’m going to have to buy a new receiver or a new amplifier, or a whole new system to do this,” but that’s not the case. If you want to do it very easily, and without concern for getting the best quality, you can get a small Bluetooth adaptor. They’re not very expensive. The quality isn’t great and it only gives you Bluetooth connectivity, but it’s a starting point if you want to look at that.

A much better option is something called a streaming player or a network player. You can think of it as a similar component, a source component like a tuner or a CD player, or a Blue-ray player, etc. It’s just another source.

Now there are many companies that make these. We have one called the AxiomAir Transformer . This is an amazing little box because it will do everything I just talked about, and actually even have some more features I’ll go over in a second. So with one of these streaming players I can now play my Spotify or my TIDAL, I can play anything from an iPhone or an iPad directly to my existing audio system, I can play things from the internet like web radio stations. I have all of that capability and I have Bluetooth capability, so anybody that has a device with Bluetooth can connect to the Transformer, and now that audio will be on your existing home theater or stereo system.

One other interesting thing is that many people have got, maybe, a vintage audio system that they love they’ve been holding onto for years, they had at college, it still works great, it still sounds great, but they want to make the sound better from their television set. Flat-screen TVs these days have really, really poor built-in speakers. The problem is, most television sets these days do not have an analog output, which is what you need if you have an older receiver or amplifier in your system. They do, however, have a digital fiber-optic optical connection and the AxiomAir Transformer actually has an optical input on it, so now you can also plug your TV into this and play wonderful-quality sound over your existing audio system.

One other benefit, if you’re a karaoke fan, you love to sing, there is an optional module that you can get that has microphone inputs, feedback-killing circuitry, and echo, all kinds of features that now will turn, you know, that home theater system in the basement into a brand new unit that’s right up to date. So this is something really to consider.

If you’re making use of these streaming music services, which are wonderful and convenient, think about adding a streaming player like the AxiomAir Transformer to your system.

But in reality, neither of these distortion percentages are audible. In our testing using non-harmonically related tones with the listening being done in an anechoic chamber the lowest threshold for detecting distortion was 0.1% and only at 10kHz and above.

If the source is music with the listening being done in a regular room the threshold is much higher than this; study here.

Going back to our distortion spec of 150 watts at 0.02% THD+N, what you will find is that the distortion will rise very quickly as you cross the rated power output, so if you turn up the volume to the point where you require more than 150 watts the distortion will rise at an exponential rate as a percentage. This is known as amplifier clipping and is very audible.

When an amplifier clips the sound becomes harsh and you want to turn it down.

To add another layer of complexity to this, music is dynamic in nature and accurate reproduction of these dynamics is very important to listener enjoyment. However, our standard specification of continuous RMS watts to judge amplifier power is very misleading. The real question is how much power can the amplifier produce without clipping for very short bursts.

Things like the amount of storage capacitance in the amplifier can be a good indicator of its ability to produce many times the continuous power for a short amount of time, resulting in accurate and distortion-free reproduction of dynamics.

Since power is logarithmic, the amount of power required to produce a 12dB dynamic peak will be 16 times the continuous power level you are listening at. This means if your amplifier has no dynamic headroom above its continuous power rating you have to divide the power rating by 16 to have enough headroom for a clean 12dB peak. Now our 150-watt amplifier has a usable continuous output for clean music reproduction of 9.4 watts.

The above discussed one aspect of non-linear distortion. But there is also linear distortion which in many ways can be worse than non-linear distortion, even if subtler, because it will always be present in an imperfect system. You cannot turn down the volume to get rid of linear distortion. Linear distortion would include an imperfect amplitude response curve from a loudspeaker.

Again, this cannot be boiled down to a one-line specification. We have likely all seen speaker specifications like 50Hz – 20kHz +/- 3 dB. This specification will represent the on-axis frequency response (hopefully measured in an anechoic chamber but not likely). Unfortunately, the on-axis frequency response is only one of many amplitude response curves necessary to evaluate the linearity of a speaker. What you really need is the Listening Window curve, the Sound Power curve, and the Directivity Index. Note that the Directivity Index will be the inverse of the Sound Power curve if the Listening Window curve is linear. Without all of this information you have no idea how much your loudspeaker is distorting the sound.

Choose an App

Gone are the days of buying CD-Gs or single tracks on iTunes – today there are dozens of great apps you can buy for the weekend or subscribe to longer-term for an ever-changing list of songs that mean everybody will find something to sing. A few to check out include Karafun, Smule, and The Karaoke Channel. Don’t want to subscribe to anything? You can find thousands of songs on Youtube – just with no options to add vocals, etc.

Choose A Mic

First, decide if you want wired or wireless. Wired mics are much cheaper and you’ll never be stuck because you ran out of batteries at midnight. Wireless mics encourage your singers to dance a little too, and that can take a party up a notch. And they’re easier to store.

At a minimum, you’ll want two microphones, and if your budget will stretch to three or four mics you’ll always have backup singers at the ready, too.

Wireless Mics:

The specs you want to look for here are cardioid (meaning that it picks up sound from whatever is directly in front of it, not a lot of background noise.) Though there are a lot of inexpensive wireless mics available, be careful, inexpensive wireless mics are notorious for distortion, background noise, and dropout. If you want to save money go wired. Here are a few very good wireless mics we recommend:

BBS U-666B
Shure BLX288/PG58-H10
Sennheiser XSW 1-825

Wired Mics:

If you hate it when things go wrong, and if you’re more likely to shooo-wap side to side than to bust-a-move when you dance, then a wired mic is an inexpensive bulletproof option. Even an inexpensive wired mic is likely to work great. You will want a Dynamic wired mic that does not require Phantom Power, this is almost all Dynamic mics. Some brands that provide good quality include:

Audio-Technica – AE6100
Sennheiser – e945
Shure – SM58

Connect to Your TV

Next step is to connect to your tv. If you have a Smart TV, you can call the app up directly on the screen. If you don’t, your phone or tablet should have an option for casting to your TV. For example, we like to have the song list showing with the Karafun app on our tablet. Then we mirror the tablet on the TV using Apple TV, giving our guests the lyrics-only view from the app. This allows us to manage the song queue in the background while people are singing.

Adjust the Mix

Either using a Karaoke Mixer or the AxiomAir App if you have an AxiomAir, adjust the balance between the vocals (the mics) and the music. This is key to a fun party: cheaper mics may not sound as good and you might want to bring the music up to make up for that. Great mics sound amazing and you’ll want to bring them forward. Adding some echo will go a long way to making everyone sound more professional.

It probably goes without saying, but this is a good step to do before your guests arrive, so you’re ready to get right to it when they come in. Once you have some settings that work you will likely never change them again, only the master volume will be used.

Pre-set the Music

One thing we’ve found makes a big difference is having a song queue at the ready. The best karaoke apps will let you slide songs up and down the play queue so as soon as someone thinks of a song they would like to try, you can add it to the list. If everyone is stumped, the songs you have in the queue will likely inspire one brave soul or another to join in. It’s a matter of keeping the music going.

1. Start with Group Songs
   Try some classic songs that everyone will want to sing along with. Depending on the age of your guests, here are some ideas:

   70s Classics:
   The Weight – The Band
   Stuck In the Middle – Stealers Wheel
   Dancing Queen – Abba

   80s Classics:
   Don’t Stop Believing – Journey
   Living on a Prayer – Bon Jovi
   Celebration – Kool and the Gang

   90s Classics:
   I Want It That Way – Backstreet Boys
   Man! I Feel Like a Woman – Shania Twain
   Friends in Low Places – Garth Brooks

   00’s Classics:
   I Got a Feeling – Black Eyed Peas
   Bye, Bye, Bye – NSYNC
   Chicken Fried – Zac Brown Band

   10s Classics:
   Uptown Funk – Bruno Mars
   Wagon Wheel – Darius Rucker
   Wrecking Ball – Miley Cyrus

2. Move to Duets
   Ease into the night with some duets if your singers are still feeling shy. A few to try:

   Just Give Me a Reason – Pink and Nate Ruess
   I Got You Babe – Sunny and Cher
   Love Shack – The B52s

   Remember to explain to newbies how they’ll know it’s their turn to sing (some apps use colors to differentiate, others use on-screen position.)

3. Lead the Charge
   Now you’re ready for the solos! By this time your guests are warmed up and confident, so hopefully someone steps forward and starts. If not, have a song or two ready for yourself to sing.

Create A Theme

A lot of people are shy and won’t know what songs they will be able to sing in their range. Rather than giving them your entire songbook and telling them to pick one, why not narrow down their choices by selecting a theme? Get your guests to dress up and pre-select some songs – they’ll have time to practice them in the car or in the shower, and they’ll feel more confident singing at your place.

Here are some theme ideas we’ve found were big hits:

Country Music
From The Gambler to Knocking Boots, from Kenny Rogers and Dolly Parton to Carrie Underwood and Blake Shelton, there is something for every skill level in country music.

Set the Stage:
A few country tidbits here and there will set the stage for your guests. Consider Bandana Napkins, Cowboy Hat snacks, and checkered tablecloths. Encourage your guests to dress up – you have no idea how a pair of cowboy boots will empower them to find their inner country singer!

Showtunes / Musicals
This is another category crosses generations and can make for a really fun night. Look at classics from musicals like Hair or Hamilton, songs from Disney classics like Frozen or Beauty and the Beast, or go Broadway tunes from Mama Mia. Beware, though – a song that is too slow can kill the party. Avoid overly emotional love songs or Jean Valjean's solo from Les Misérables.

Set the Stage:
Costumes, costumes, costumes! Have your guests dress up as the main character from one of the songs they’re going to cover. Encourage props too!

Family Theme
Have some family joining you? Why not try a family theme? Choose songs that have a family moniker in the title or band: The Mamas and the Papas, The Everly Brothers, Twisted Sister, I’m My Own Grandpa, He Ain’t Heavy, He’s My Brother, We Are Family – you’ll be amazed at the variety that comes up with this theme.

Set the Stage:
Have some classic family photos printed and blown up to have scattered around the room. Make a few classic snack recipes (Ruffled Chips and French Onion Dip might take everyone back to their childhood, or some other classic.)

Road Trip Theme
If you ever took a family trip across the country, you’ll know that having a good playlist was key and singing along was mandatory. Recreate that feeling of freedom by selecting songs about places, about travel, and about being together in the car. Fast Car,New York, New York, Austin, This is How We Roll, Roll Me Away, and Drive My Car will get things going.

Set the Stage:
This one is fast – Route 66 posters, street signs, and classic diner menus will do the trick.

Retro Tunes
Of course, determining if something is retro depends on how old you are. However, this is another fun theme to choose – 60s tunes, 50s tunes or just anything by someone you’d consider a crooner.

Set the Stage:
Serve retro snacks like devilled eggs, angels on horseback, or fondue, and have everyone dress up in costume. A selection of fedoras, wigs that mimic old fashioned hairstyles, or a pair of Elton John sunglasses will inspire songs too.

Have you hosted a home karaoke party? What did you find the biggest hit with your guests? Let us know in the comments below!

First Up: The Music

Think of this as your virtual digital record crate. Download music (because you don't want the party to stop if the cell signal is bad!) to your laptop or tablet. Find tracks in the highest resolution you can get, because you're going to be playing loud and quality matters!

Beatport is a 15-year-old DJ music store. They offer premium digital music tracks curated by professional DJs that encompass all kinds of genres from Afro House to Garage to Indie Dance to Dubstep to Reggae and Dance Hall - you're definitely going to find something you like here. You can check out the top charts in each genre, or follow a specific DJ to see what they're featuring these days.

Bandcamp is another long-time music source. This is a great place to find complete albums by new artists. It's an indie-friendly storefront that's perfect for people looking for new music.

SoundCloud is a great way to find new music, often for free as producers try to establish themselves. It's also a good place to get previews on tunes that link to iTunes or Amazon where you can purchase full tracks.

Next, The Control Surface

Now you need to get the music from you laptop or tablet to someplace where you can mix it. An easy way to do this is to connect via USB to a controller.

Controllers range from entry-level to hosting-a-party-in-Rio. Numark is a popular brand that comes bundled with Serato Mixing Software. Here are a few models to think about:

• Numark DJ2GO2 - this ultra-portable machine is easy to learn, lightweight and compact, and works with both Mac and PC.
• Pioneer DJ DJ Controller - you'll find lots of Pioneer machines on the pro circuits. This one includes 2 headphone monitors and XLR and RCA connections.
• The Numark NVII Professional DJ Controller really takes things up a level: two full-color displays help keep beats matched for perfect crossfading. Includes the professional version of Serato DJ and toolroom remix packs.

Controller brands popular in this space include Pioneer, Roland and even Denon. For more mixing software options, check out Traktor, Virtual DJ, or if you have a Mac, Mixxx open-source software.

If you have a Tidal account, create tracks in the cloud: Tidal is built in to the Serato app.

If you already have a Spotify subscription and a Mac, consider DJay Pro: it integrates Spotify natively so you can test songs, try out new mixes, and then buy the music you want to work with.

The Preview: Headphones

So far we've got our music, we've got our mixer - but how can we hear what we're doing before we share with an audience? Headphones. Eventually, you'll be in a venue with a lot of noise, so investing in quality headphones with good full-ear coverage is key.

Things you should look for:

• Lightweight - you might be wearing them for an 8-hour party - you don't want your neck to hurt.
• Durable - DJ stands get messy and perfect equipment control is unlikely. Get headphones that can take some abuse.
• Full coverage - whether on-ear or over-ear, you want to be sure you can block out room noise to hear over party noise.

Here are a few models to check out:

• Sennheiser HD 25 - probably the most popular choice for DJs, including Calvin Harris and Afrojack
• V-MODA Crossfade M-100 Master - stylish, well-built and above all comfortable
• Shure SRH750DJ - with a frequency response of 5hZ - 30kHZ, what they lack in style they make up for in quality.

I can say with certainty you will never read this anywhere else on our website, but this is one time where a flat, neutral sound may not be what you are looking for. DJ'ing is really dependent on good bass, so buying headphones that emphasize bass is a good idea.

Finally: The Speaker

Okay, you're all set: you have your mixing board and software, your tracks and your headphones. Now, how to share the music?

Easy as pie . . . Raspberry Pi, that is! If you've got an AxiomAir N3 Force, simply use the RCA output to connect to your controller, and you're there!

What's important in a portable speaker is bass. Bass is primal. Bass makes us want to move. And speakers with poor bass response will not get the party started. So pay attention to this spec when selecting your DJ speaker.

Putting it All Together

One of the AxiomAir programmers, MadBeggar, has been DJing in clubs for decades. Here's a video showing his set up using an AxiomAir, a Numark, and a computer.

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If you know and love local radio stations but you have trouble finding their feeds or streaming links, then you'll love this option in the AxiomAir app. TuneIn brings you live sports, music, news, podcasts, and internet radio from around the world.

A post shared by AxiomAudio (@axiomair) on Nov 10, 2019 at 9:59am PST

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High quality streaming services like Tidal make music listening even more intense. If you're subscribed to Tidal, follow these simple instructions to add it to your AxiomAir App and stream music directly from the AxiomAir App on Android, iOs, or web.

A post shared by AxiomAudio (@axiomair) on Nov 11, 2019 at 3:27am PST

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Wondering how to use Spotify Connect with your AxiomAir speakers? It couldn't be easier! Find out how in this video.

A post shared by AxiomAudio (@axiomair) on Nov 10, 2019 at 8:30am PST

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Here's how to play music from a USB drive inserted to your AxiomAir. Whether you're out of wifi range or you've ripped your CD collection to a USB, you can easily play music or other audio from a thumb drive.

A post shared by AxiomAudio (@axiomair) on Nov 10, 2019 at 9:09am PST

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If you didn't name your AxiomAir when you were initially setting it up, it's not too late! Whether you are adding another Air to your network or you just want to see your devices clearly on your network, here's how to customize your speaker's name.

A post shared by AxiomAudio (@axiomair) on Nov 10, 2019 at 9:22am PST

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Putting your AxiomAir on your network enables multi-room playback and gives you the option to stream music without using a data plan

A post shared by AxiomAudio (@axiomair) on Nov 11, 2019 at 2:09am PST

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If you've never downloaded the AxiomAir App or scrolled through its settings, you might not know that you can set a sleep timer on your speaker and have the music turn off or even have the speaker power itself down automatically. Watch this short video to find out how!

A post shared by AxiomAudio (@axiomair) on Nov 13, 2019 at 3:25am PST

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Want to wake up to your favorite music every day? With the AxiomAir App, it's as easy as creating a great playlist and setting the alarm time! Watch this short video to find out how.

A post shared by AxiomAudio (@axiomair) on Nov 13, 2019 at 5:15am PST

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Building the AxiomAir on a microcomputer means that you don't need to change out hardware just to get the latest software - you can update your speaker's operating system and get the latest version any time.

A post shared by AxiomAudio (@axiomair) on Nov 13, 2019 at 6:09am PST

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Just crawled into bed and realize you left your AxiomAir on downstairs? No problem - here's how to use the app to shut it down without your feet touching the ground.

A post shared by AxiomAudio (@axiomair) on Nov 13, 2019 at 8:44am PST

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Have more than one AxiomAir in your system? Playing music on both - or all - of them at once is as easy as drag-and-drop. Find out how in this short video.

A post shared by AxiomAudio (@axiomair) on Nov 19, 2019 at 5:30am PST

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Customize the background of your AxiomAir App.

A post shared by AxiomAudio (@axiomair) on Oct 21, 2019 at 4:02am PDT

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Web radio stations allow you to listen to stations from all over the world easily and simply on your AxiomAir system. Want to know what's trending in Europop, or visit a jazz club in Australia? With web radio through your AxiomAir App, it's as easy as 1-2-3!

A post shared by AxiomAudio (@axiomair) on Nov 10, 2019 at 10:09am PST

Music streaming is simple enough once you get into it but wrapping your head around it all can be a challenge. With all of the options for streaming services, web radio, and other Internet-based music, it can be hard to figure out where to start or which streaming options are best.

Smartphones are great because they are portable, they have plenty of storage space, and they have access to all kinds of streaming apps. However, what if you want to carry more music than you have room for or if you’re looking for a new way to enjoy wireless music with the help of the internet, streaming could be just what you need.

With this guide, you’ll be on your way in no time.

What Is Streaming?

Streaming services work on a very simple principle. They offer music, on-demand, that streams over the Internet. Various services have different interfaces and types of music systems available. For example, Pandora Internet Radio offers the option of suggested stations that learn to play what you like. However, they have also joined the likes of Apple Music and others that allow you to stream your own created playlists and songs so that you only listen to the music that you want to hear.

You need some kind of smart device to stream music because it requires an Internet connection. Today, however, that could be a tablet, a laptop, a smartphone, or even a smart home assistant speaker like the Amazon Echo or Google Home. Beyond that, a good pair of headphones or speakers are all that is holding you back from enjoying your music whenever you want.

Streaming Services

Most streaming services offer free and paid memberships or subscription plans for users. Free platforms often have limited features or require the use of ads, but this can vary from one platform to the next. The best way to learn about music streaming is to look at the different services and what they have to offer.

Keep in mind that because of the way that laws and regulations work in the music industry, some platforms may not be available in all countries or areas. Most services are heavily restricted when it comes to location so that they can keep up with the laws and regulations. Therefore, they may only be available in certain regions. Many services today, including Apple Music, are global streaming services.

Spotify

Spotify was among the first streaming services to offer the chance to curate your own playlists, aside from industry giants like Google Music and Apple Music. Spotify has a user-friendly interface, an extensive catalog of available music, and better device compatibility than a lot of services. There is a free platform available that has recently been improved, making it among the best free streaming services available today. Upgrading to premium increases the number of playlists that you can create and how you can enjoy your music.

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Google Play

Google Play Music is a great choice for users who want to use the ad-free service offered by YouTube Red. This platform is also popular among users with Android devices who want to include their personal music library in their streaming list. Many internet streaming services don’t offer integration with your own music collection. Google Music is also compatible with the Google Home smart speaker. Cloud storage seems endless and you’re really only paying a small fee to get rid of ads.

Apple Music

Apple Music is one of the most popular streaming services, and it is also one of the most comprehensive services on the market today. This platform offers the opportunity to combine all of your streaming music with CDs that have been uploaded, Apple radio stations, and other sources of music. Apple Music offers integration with Siri and Apple smart home devices. This service offers free use of the online music library, but in order to access most streaming services or listen freely offline, you will have to upgrade to a paid membership.

Amazon Music

Amazon Music remains a popular choice in streaming simply because It’s an Amazon product and some people are dedicated to their brands. Amazon Music allows users to stream music or purchase songs for download. This service is also preferred by people who happen to already be Prime members because they can keep everything incorporated on the same account. Amazon also provides this free to Prime members. It does have a smaller library and fewer features than other services, so keep that in mind. This service is ideal for those who want casual streaming with less effort. Their new Amazon Music HD with high-res files (available in the US) is a welcome new feature, too.

Tidal

The selling point of membership with Tidal is that users with premium membership also enjoy higher quality bandwidth, which means that you will be able to take full advantage of better-than-CD-quality sound. Tidal was launched in 2014 and is partially owned by Jay-Z, Beyoncé, Kanye West, and other artists. This service is available in 52 countries and comes with a 30-day free trial for offline listening. There is a new section on the app dedicated to HiFi members looking to stream with MQA encoding, which means you enjoy the closest feeling to that analog vinyl sound on modern technology.

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Pandora

Pandora Internet Radio allows users to listen for free as long as they are willing to listen to ads. The app also sponsors ad-free hours with an extended advertisement. Until recently, Pandora only offered a radio station that was curated for you based on your music tastes. Now, it also offers a streaming service where you can listen on demand. This requires a paid membership, which will also remove ads from the site.

YouTube Music

YouTube Premium gives users access to YouTube Music, where they can stream all of YouTube’s content, enjoy background listening, and enjoy ad-free songs and videos with a paid membership. Because it is owned by Google, members enjoy Google perks, as well. The music and videos are separate on this app, however, and there is no desktop app available. Users can access it from the mobile app or an internet browser. Thanks to the inclusion of the YouTube library, this is one of the most comprehensive services available.

Web Radio

Web radio is a specific type of streaming. Unlike the services listed above, web radio apps and stations specifically play radio stations. Some include local stations that you would hear on the radio, while others are entirely new Internet radio stations. Web radio occurs in the form of pre-recorded mp3 files, or more commonly, live broadcasts that are streamed into an app or website over the Internet. The perk of Internet radio is that it can be listened to from anywhere.

The other major benefit of web radio compared to other forms of music is that you can listen instantly. You don’t have to wait for something to download music onto a hard drive or try to figure out how to get your favorite stations when you are out of town.

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Finding Your Favorites

So, if you want to look up some of your favorite local (or out of town) stations on web radio, how do you find them? It’s really easy these days, thanks in part to the popularity of internet radio and advertising it on traditional radio. All that you need to know are the station call letters or the dial number. If you’re looking for an internet station that you’ve heard about, you can usually just search it by name.

Another option for finding stations is to listen to the advertisements on live radio. Usually, whenever there is a station plug, they will also promote whatever Internet radio app they use to stream their station online for fans. For example, a lot of regular stations use the Radio.com app or the iHeartRadio app. Some stations will even have full commercials about the web radio service that they use.

A third option is to check out TuneIn Radio. This is a great way to find your local station.

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The bottom line? If you search, you will likely find it. There's something surreally comforting about being in a foreign country but still being able to listen to the sports scores and traffic reports from your town when you get a little homesick.

Popular International Channels

Here are a few popular global web radio stations that you can check out to get a sense of what’s out there:

• WLTW 106.7 Lite FM: This New York-based station offers a variety of music from modern day pop to 80’s rock and everything in between. The app only shows the three most recent tracks, but it does offer some song lyrics, as a bonus. This station is owned by iHeartMedia.
• NSB Radio: This is among the best party radio stations on the Internet. The station offers dance, techno, dubstep, house, and other related genres. the station also broadcasts live daily.
• Kool 97 FM: If you like old-school and new-school Caribbean music, this Kingston, Jamaica channel is sure to transport you. A little reggae brightens up any dull day!
• RTE Junior: Have little ones in the house? How would you like to have a wee lovely Irishman telling them a story every day? This children's channel from Ireland has lots of features that will delight the youngsters (who will undoubtedly know how to change every device in the house to this station, because kids are that good with technology.)
• SomaFM: This San Francisco station is great for those who love indie music. This is a commercial-free station that offers a variety of listening options. There is also a sleep timer option.
• Otto's Opera House: If you love Opera, then this Zug, Switzerland channel will soon before a favourite. It plays Opera 24 hours a day, encompassing three centuries of the genre.
• KEAN 105.1 FM: This country station calls itself Texas’ best country radio station, playing everything from top hits to classics. The station runs on a mobile device or browser. The only big issue is that when you’re listening in the browser you have to stay on the page or the music stops.

Digitizing Your Collection

Now that you know a little more about Internet radio and music streaming, you probably want to get your existing music on the same platform. Fortunately, digitizing your music is a fairly simple process these days. Most computers have a CD-ROM drive that is capable of reading and ripping music from the data. Those that don’t can be outfitted with an external drive that can be hooked to the computer via USB. Then, you simply choose a program to import the music and get to work.

There are a number of programs that you can use to copy a CD to a digital format. You can use the simple media player or music service that came preinstalled with the computer, in a lot of cases. You can also invest in high-quality copying and ripping programs that will ensure sound quality and integrity. Some people who aren’t very computer savvy even choose to hire someone to do the digitizing for them. There are plenty of services available, or you could even ask a family member or friend to do it for you.

The biggest question you need to ask is whether you’ll store your music on the cloud or on your device’s storage. Local storage is ideal for offline listening, as well as for situations where signals may not be very strong. Hikers, campers, and others who spend a lot of time in remote areas may prefer to have their music directly on their device. If you have a really large music collection that you’re going to rip at full resolution, you’re going to be storing over 100GB of data – possibly well over that, and that could get costly with a cloud service. On the plus side, though, cloud services offer the security of redundant backups so you can recycle all those old CDs once and for all.

Multi-Room Playback and Other Streaming Perks

Once you have all of your music accessible from your network or the cloud, it’s time to turn up the volume and enjoy your hard work. Another benefit of streaming as opposed to listening to CDs is that you can enjoy multi-room playback when you have an ecosystem like the AxiomAir in your house, which allows you to add and remove speakers from a group. You can also enjoy it when you invest in a smart speaker that is compatible with your device via Bluetooth. In both cases, you can turn on your music in one room and hear it in every room of the house simply by telling the system to turn on all of the speakers.

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The Big Question

So you know you can have your music, your way, anywhere you have an internet signal. And if you don't, then you can play your music from a source you've saved your music to, like a thumbdrive or other storage device.

But do you have to buy new speakers to enjoy this sort of newfound musical-world-at-your-fingertips?

Fortunately, the answer is 'no'! With a device like the AxiomAir Transformer, you can make any pair of speakers available wirelessly, and they will have access to Web Radio, streaming services, a USB drive full of music - you name it. It's available in horizontal or vertical configurations, and it's easy to use - plug it into an available input in your existing wired system such as 'Aux', and that's all there is to making that input an AxiomAir. Use the AxiomAir App to play music or connect via Apple Airplay or Spotify Connect among other options.

If you get your Transformer set up and fall in love with the convenience of controlling music from your phone, tablet, or laptop, you can add more wireless speakers to your home, and they'll become part of your AxiomAir network.

Streaming Is Now

Many people will still try to tell you that streaming is the future of music. Considering that there are over 70 million smart speakers and more than 200 million smartphones throughout American households, streaming is already happening and it is taking hold very quickly. Of course, it’s about more than music. Most streaming services also offer talk radio, podcasts, audiobooks, and other non-music stations, giving users the chance to listen to whatever they want, whenever they want.

Have you dipped your toe into streaming music and the delights of web radio? Let us know any favourite stations, streaming platforms, great podcasts or sources for audio books in the comments below.

The problem is that you probably already have a much better sounding stereo home theater or speaker system in your house, something that's likely going to sound a lot better than even the biggest Amazon echo. So what to do? Well, even if you've got an old stereo receiver you can apply modern technology because of the features that Amazon has built into these products to any system.

So let's assume first that you have a receiver or a home theater receiver or a stereo that has standard RCA inputs, on the back of the device, and this goes for all of the echos, there's a three-and-a-half millimeter analog output all you have to do is buy a cable that goes from three-and-a-half millimeter to stereo RCA. Plug one end into the back of the echo and the other end to a free input any auxiliary tuner or any input that's not being used on your receiver amplifier whatever.

If you have a wireless speaker that you want to use that already has a three-and-a-half millimeter input, you just need to get an adapter cable that's three-and-a-half millimeter to three-and-a-half millimeter. Now, if you've got a modern wireless speaker system that you want to use and it has Bluetooth, guess what? These devices have built-in Bluetooth you can connect wirelessly to any Bluetooth speaker, Bluetooth audio device, some home theater receivers also have Bluetooth capability now it's totally seamless no wires and you can talk to Alexa and tell her exactly what you want to listen to.

Let's face it: home theater systems are pretty confusing things for most people to set up. There's lots of different speakers. There's electronics. There's streaming players to hook up. There's Blu-ray players. There's all these things that can seem complicated to get right. And that's just something that comes with experience.

But there are a few things that I commonly see people doing that are no-nos. And they're not no-nos because they're going to break something, they're no- nos because they're not getting the full potential out of the equipment that they paid for. And that's no good.

Surround Channel Mistakes

But the other thing that I find with surround channels is people seem to want to place them as close as they can to where their couch is or where their sitting area is. That's actually not a good idea. It ruins the immersive feel. You want to get the speakers ideally behind the listening position a little bit, even if it's a few feet.

Certainly, don't have them in front of the listening position. That's something I see very commonly. And you get the argument about, "Well, it only fits there and whatnot." We and other companies make all kinds of speakers for different applications. Find the one that's going to work to place your surround channels the best.

Believe me, it makes a huge difference. If you can hear and pinpoint exactly where your surround speaker is, if you're in a movie where you've got a natural environment, you're outdoors, there's a problem. Set it up so that you don't have that happening.

Auto Set Up

So the next thing that is a big pet peeve of mine and I'm probably going to get a lot of comments that I don't know what I'm talking about, "My system works better this way."

My personal opinion is when you first set up your home theater system, don't take the easy way out and press that auto setup button that's on the front of your receiver, get the microphone out, press the button, or go into your menu and say, "Auto set-up." I hate them. Now, it's not because they don't work in some applications. That's not what I'm saying.

What I'm saying though is that they will change and modify the intention of the design. Designers go to a lot of effort to make our speakers sound very neutral, and many of these systems will try compensating for something in the room that isn't actually the speaker's fault, and you'll end up with something that's too bright or too bass-y or not enough mid-range or whatever.

I get calls all the time. "My speakers are sounding a little bit thin. They didn't sound like that when I came to your factory to listen to them. Why is that?" "Did you use the auto setup?" "Yeah, I did because that's what the manual said."

Doing a manual setup for a home theater system is not a two-minute process. It's going to take you half an hour or an hour. I suggest doing it because A, you'll familiarize yourself with the menus and controls on your receiver, if you don't already know them. But B, balancing levels by ear is way better than any measurement system or microphone can do.
And at least, live with the system where you manually set it up for a while, and if you're not happy, sure, try the auto setup. Try it just if you're curious, but I guarantee you that in most cases, it's going to sound better without the auto-correction system running.

Subwoofers

The final thing is subwoofers. We love subwoofers. We love bass.

Everybody loves bass, but too much bass, I think, ruins the sound of a system. Balance is the key here. You've paid money to buy a good pair of loud speakers, a good center channel, good surround channel, a good subwoofer so that they're neutral, so that they don't accentuate a certain frequency band or area.

But then, typically, people have got the subwoofer level jacked up 3 dB, 6 dB, 10 dB above everything else. Now again, if you like that, go ahead. I'm not going to stop you. But if you want to get the most natural experience, particularly with music, or music video material, concerts, get the subwoofer balanced to the rest of the speakers. It's not very difficult to do.

If you go back in our archive, you'll see a number of subwoofer setup videos and suggestions. Go and look at them. Set your subwoofer up to a pleasing level that matches the rest of the speakers and just listen. Again, if you can pinpoint the subwoofer, and it sounds like it's working really hard even if you're listening quietly to something that doesn't have a lot of bass in it, to me, that's not right and it's not the best experience you could get.

So hopefully, those are a couple of tips and things to watch for when setting up your home theater system.

There’s a few reasons that we recommend doing that to get the best performance from your system.

The first is with a modern home theater processor or receiver, there is a lot of digital circuitry in those systems. Those digital circuits produce noise, and that noise inevitably, no matter how well designed, at some small level, is going to get into the amplifier section.

If everything is driven from a common power supply and is all in the same chassis or the same enclosure, which is exactly what you had with a receiver. Once you split the amplifier from that, even though you’re running external cables, you isolate the power amplifier by being on its own from that noise, from that potential to interfere with the signal to the amplifier. It also has its own enclosure, so it’s immune to any radiated noise that may be coming through the air.

That’s one reason why if there’s a benefit. The other reason, and I think the bigger reason, is that if you think about a typical home theater receiver, you’ve got tons of circuitry. You’ve got an amazing amount of complex electronics inside that box and they’re all powered by, usually, one power transformer. Now, that power supply to fit into the box with all those other electronics and all those multitude of amp channels, we’re seeing now receivers with 11 amplifier channels in them. They all have to share that common power supply and what will happen inevitably is that some compromise has to be made to actually fit all that stuff in the box.

And the biggest components in any piece of electronics, like a receiver, is the power supply. Particularly if it uses a traditional transformer and capacitor rectifier power supply configuration.

So what does that mean? Why do I care? So the amps are in the same box and they share that power supply. Well, that power supply usually will not be overbuilt, and by overbuilt, I mean it’s bigger than it needs to be so that you can have dynamic headroom. That means the amplifier can exceed its maximum power specifications for short periods of time. When you have an external power amplifier, that power supply has been designed and dedicated just to the amplifier section itself. It’s not sharing power with the rest of the components.

So what happens is that you can get better dynamic headroom in most situations with that external amplifier.

Now, if I don’t listen very loud, why do I care about that?

Well, if you think about let’s say movie program material, you can have it a very comfortable listening level. You can hear the dialogue well and as we know, in action movies and other films like that, you can have a sudden explosion or a gunshot or something that instantaneously requires – in some cases – 10 or 20 times the amplifier power then the vocal track that you were just listening to, or the voice track. So what happens is that when those dynamics are reproduced accurately, because you have that extra power in on-demand on top for short periods of time, it’s clean, it’s clear, and it frightens you, and that’s exactly what it should do.

The movie mixers and producers have made those effects louder so they startle you. So they get an emotional response from you.

If you have a system where you can’t have that clean power available because the power supply can’t deliver more than the rated amplifier power, the dynamics are going to be squashed. That means that special effect isn’t as impressive, it’s not as scary, you don’t have the same emotional reaction, and it’s just not as fun to listen to.

So that’s one reason why we recommend in most systems beyond the certain level that if you can afford it, a separate power amplifier is a very good idea to get that clean dynamic power.

So should I care? Should you even bother with that in your home system? Well, I like to use balanced connections where they are available in certain applications and I'll run down exactly why. So first of all, what we have to understand is that balanced connections, just like RCA connections, you need to use the same connection on both ends.

There is absolutely no point in connecting an XLR on one end and having an RCA on the other. You get zero benefit from the balanced connection because internally, all that's happened is that one of the connections with a balanced connector isn't going anywhere. So there is no point in doing that. Save your money because balanced connections and cables usually are a little bit more expensive.

So assuming you do have two components that have XLR connectors on both ends, should you use that connection? Well, if you can afford the additional cost, there are benefits. The difference between a balanced connection in audio equipment is usually something that's run, what we call differentially.

Now, I'm sorry I'm going to get into some sciency stuff for one second. So in a typical RCA connection, there are two contacts or two conductors. You have the center pin and then you have the outer pin. The outer pin is always the ground but that ground in a two-wire system like an RCA is also the return.

What it means is that we need a complete loop, a complete circle for an electric connection to be made and to flow. So what happens is that that ground connector is not a dedicated connector. It's part of the signal loop. In a balanced connection, you have a positive and a negative connector inside the XLR that are, in a differential system, they're running out of phase to one another.

So they're inverted to one another. Now, I haven't said anything about ground. Now, the ground in an XLR connector is made up of both shield and pin one, it's called. But those things are separate to the electronics that are driving positive and negative pins out that XLR connector. So why does that matter? Well, at the receiving end, so let's say your amplifier or your subwoofer, there's going to be something called a differential amplifier.

That amplifier will only respond or amplify signals that are different between the two pins. Because the two signals are out of phase in an XLR connector, it means that when, let's say a sine wave signal moves, that when there's a peak and a valley that correspond at the same time, it's going to amplify that difference.

But if we have a noise signal, and that noise can be coming from anywhere. It can be radiated from the air, it can be interference from other electrical equipment, it will appear in the same phase on those two conductors. And so, when the difference amplifier looks at those two noise signals, they're exactly the same and they're cancelled out.

So what you end up having is you have a conductor and connector that's much more immune to any sort or form of noise. But also note, again, I didn't say anything about the signals traveling on the shield or the ground connector. That's because in an XLR or a balanced system, that doesn't happen.

So, if you ever run into a ground loop, and they are easy, easy in home theater systems, because typically, your subwoofer is going to be located far away from your equipment rack and probably on a different AC circuit in your house through a different breaker, that sets up a potential for a very, very good and nasty-sounding ground loop.

If you use now a balanced connector in place of an RCA, an XLR connector, it will break that ground loop. So for things like subwoofers where you have a longer cable run and ground loops are very possible, I always recommend XLR. Unfortunately, a balanced subwoofer output is only normally found on the highest end, and hence, most expensive home theater receivers and processors.

But if you have it, use it. If you don't, don't worry about it. In most cases, there's other solutions if you have a ground loop and, you know what? We're talking about those really noisy environments like living next to a cellphone tower that are really going to make a big difference between the two cable types.

So don't lose sleep if you only have RCA.

This is a number that speaker manufacturers will give in ohms, usually eight ohms or four ohms, as something that's called the impedance or the nominal impedance. Now, why people get concerned about this is that you'll see lots of forums on the internet, people saying, "Oh, if it's a four-ohm speaker, you shouldn't connect it to a home theater receiver or a cheap home theater receiver because you'll blow it up, it will overheat, something will happen."

Now, we'll talk for a second about the basics of what does that number mean? What does it represent? And the reality is the number doesn't mean a lot. It's just a standard that we use to give an indication of how hard the speaker is to drive, or what kind of load it presents to the amplifier. Now, we're all familiar with the term load.

If I have a 10-pound load of bricks and 100-pound load of bricks, we know the 100-pound load is going to be a lot heavier and a lot harder to lift, right? So it requires more work, more energy to lift that 100-pound pile of bricks compared to a 10-pound pile. The same thing applies to loudspeakers. The lower the impedance number, so let's say a four-ohm speaker, is a harder load, requires more work to drive, than an eight-ohm loudspeaker.

Now, where this comes from is from Ohm's law. You may remember this equation from high school, and I'm not going to get into a lot of math, but basically, if we have the same voltage and the voltage signal is coming from your power amplifier, it follows the music signal. If we have a certain voltage across a certain resistance or a certain impedance, that equation says that voltage over resistance gives you the current.

So if we have a speaker that's eight ohms, it gives you a certain current. If we now put a speaker that's four ohms into that equation, now we get double the current which means double the power is required. So this is why people say that, you know, a lower impedance speaker is harder to drive and will say that some amplifiers or receivers are not capable of driving them.

Now, the reality is is that number is not a consistent number. Speakers are not resistors. They don't present a perfect four-ohm or six-ohm or eight-ohm load to the amplifier and that's because there are components in the speaker, the voice coil that's in the drive units, the crossover components that are made up of capacitors and inductors, all of these things change the resistance with frequency.

So if you've ever seen an impedance curve for a loud speaker, you'll note that it's a bunch of hills and valleys where the resistance is changing with frequency and that's because of these components that are not pure resistors. They don't provide a simple ohms measurement at all frequencies.

Those components are called reactive components and I'm certainly not going to get into reactants and phasing or difficult things like that. What, basically, you need to know is that a four-ohm speaker is going to present a harder load for an amplifier to drive. All you need to make sure of is that the manufacturer of the receiver or the amplifier that you're looking at purchasing or that you already own, states that it's capable of driving the load that you want to drive.

So if you have a four-ohm speaker, make sure it says it's four ohms compatible. It's that simple. Now, is that four-ohm speaker on a receiver that doesn't say it's four ohms compatible going to damage it or blow it up? No. Not likely. And it's probably in most cases going to be fine unless you listen at very, very loud levels.

A good receiver or amplifier, when presented with a load at a high level that it's not happy with, should just nicely shut down and go into protection and not cause any damage. So basically, that's the reality of loudspeaker impedance. Don't worry about it, don't be frightened about it. Just make sure that the equipment that's driving it is compatible for that load.

Compare a heavy-gauge cable, like a 12-gauge cable, to a 24-gauge cable. The heavier-gauge cable has a lower resistance. What that means is that you get a better transfer of power from your amplifier to your loudspeaker.

Why Is Power Transfer Important?

If the transfer isn't optimum - and it wouldn't be with a long run of this thin little cable - you're actually going to lose some of your amplifier power in the cable. And there is no need for that. That just doesn't make any sense. You're throwing away available power to your speaker just because you haven't used a good quality heavy-gauge speaker cable.

Sounding Thin?

One other problem is that if you use a very thin-gauge cable, you can actually start modifying the sound of the speaker. People don't realize this, but if the resistance of that wire is high enough, it now acts as another crossover component that's in series with the loudspeaker and can actually cause you to lose bass performance.

So What Gauge Speaker Wire Should I Buy?

What we recommend is if you're going to be using runs that are less than 20 feet, anything 16-gauge and heavier is appropriate. And that's a lower number, so 16, 14, 12-gauge, is a good idea.

If you're going to be doing runs that are longer than 20 feet, I always recommend you should use 12-gauge cable. The longer the run, the more resistance.

If you're going to be running through ceilings and walls and things like that, use the heaviest-gauge cable that you can. You'll be getting every watt of that amplifier power you paid for to the speaker.

Even two subwoofers can do a much better job giving you nice, linear base. So the problem comes up as to, well, how do I wire multiple subwoofers?

First, the easy way: there are some home theater receivers and processors on the market that have more than one sub out on them.

Usually, it'll only be two if it does have more than one, and in that case, it's very straight forward and pretty much self explanatory. You're going to run a separate usually RCA cable from each of the sub outs on your receiver to the RCA inputs on your two subwoofers.

If, however, like the vast majority of home theater receivers in the market, there's only one labeled sub out on the unit, you have a couple of options.

One option is that you can use an RCA splitting cable where you will plug one end into the sub out on your receiver and now you have two outputs that you can run individually to the two subwoofers.

The only problem with that is that typically, the subwoofers are placed quite a distance away from the electronics and you may have to run two fairly long cables to connect up the two subwoofers.

A better option in those cases is actually to do something called daisy chaining which allows you to bring the single sub out connection from your receiver to the input of your first subwoofer.

Now using the low level output on the first subwoofer you can now join to the input of your second subwoofer amplifier.

So now we've chained these and the other benefit of this connection is if you had more than two subwoofers, three or four let's say, you can keep chaining them in this manner, going from the input on one to its output to the input on the next subwoofer out of its output to the input on the following subwoofer and so on.

So, that's the method that you're going to use to connect up your multiple subwoofers. How many are you running in your set up , and which method did you use?

There are some cases, however, where you're going to be using a conventional stereo amplifier to drive the subwoofers, so there are some adjustments that you need to set. The first adjustment, and probably the most obvious, is the volume level, which sets how loud the subwoofer is going to sound for a given input signal.

Now, we recommend that, if you're using a home theater receiver or processor, to set the volume as a starting point at the midway point. And then from there, you can make the more fine adjustments using the Setup menu in your Receiver. There is also a control on the back of the subwoofers that allows you to set a crossover frequency.

In some cases, it's just a two-position switch that allows you to set 80 or a 150 Hertz. And in other cases, it's going to have multiple settings, from 40 Hertz all the way up to 150 Hertz. Again, if you're using a home theater processor, you want to put the Crossover in the highest frequency setting which is the 150 Hertz, and then you're actually going to set the crossover point inside the processor or receiver.

If you're using a stereo amplifier and you don't have bass management available to you, you're going to now set that crossover point for whatever makes sense with the speakers that you're using. Typically, a bookshelf speaker, an 80 Hertz setting works well.

And if you have the option and you're using larger tower speakers, something like the 40 or 60 Hertz setting may work better. But it's something you have to try and see which blends the best. There's another setting called Phase, which is in degrees. There's a 0-degree setting and a 180-degree setting.

This is the setting that confuses people because if you just flip the switch with music playing, immediately you're not going to hear very much of a change at all. This switch really defines how the subwoofer is going to interact with your main front speakers. And to set it up is fairly simple.

First, play some music that's got some good bass and mid-bass content in it, and then listen to the music playing with the switch in one position, and then switch it to the other position and listen again. And what you're looking for is a setting that gives you fuller and slightly louder bass.

And that's usually the correct setting.

Finally, we have an input on our subwoofers that's labeled Trigger. And there's an In and an Out available. The Trigger simply allows you to turn the subwoofer amplifier on and off remotely from your home theater receiver or processor so that when you turn the power on and off with your system remote control to the receiver, you'll actually be switching the amplifier in the subwoofer on and off.

This is a 12-volt trigger which is fairly standard in the industry, and it simply uses an 8-inch phono plug. So you're going to bring that signal from your processor or receiver and plug it into the trigger in on your subwoofer amplifier. Now when you turn the electronics and the rest of your system on and off, it's going to switch that your subwoofer amplifier on and off.

You'll know that that's happening because normally the light on the back of the subwoofer will be green. If it's in the standby mode, because you shut off the electronics from your receiver, it's going to now turn red, so that you know that it's in the Off position.

Have you had any surprises switching between sub inputs? What has worked for you? Let us know in the comments below.

Hi, I'm Andrew Welker, Axiom Design Engineer. And today, we're going to do a sort of preliminary introduction to where to place your subwoofer in a room. Now, subwoofer and the way that it behaves and interacts with a typical listening room is a very, very complex subject.

And there's all kinds of tools and measurement systems and other things that will allow you to get very, very precise ideas of where you can place the subwoofer for the best response. But, a lot of those techniques don't work well if you don't have a reasonably good starting point.

And conventional wisdom says that you want to take your subwoofer and just slap it in the corner of the room. Now, in many cases, that will give you the loudest bass, but in most cases, it won't give you the smoothest and most linear bass. So, it's a decent starting point, but don't assume that once you've put the subwoofer down and in place, that it should stay there necessarily.

If you're forced into a certain location...and in many homes, the only place that you can put your subwoofer is close to the television set, which usually means that it's going to be behind either the left or right loudspeaker, and probably in the corner, unless you've got an L-shaped layout.

The corner placement is going to give you the biggest amount of what's called, room gain, which is additional output because of the loading of the room boundaries, which we mean the walls and the floor. If you are limited in terms of your placement, you should always, even if you only have a couple of feet to play with in any direction, you should try pulling the subwoofer out from being right up against the corner, moving it to the left or right by a few feet as much as you can.

And as you do this, listen to music that you're familiar with and try and find the position that gives you the smoothest bass. Even a couple of feet of pulling the subwoofer out from the corner can smooth out the bottom end significantly. Now, if you have two subwoofers in your set up, and again, you're fairly limited, you're going to do exactly the same thing.

I always like, when I have two subwoofers is to actually set them up in terms of looking for the best placement separately, and then balance the levels and make the adjustments with both of them playing after you've found a good position that gives you the smoothest bass for each subwoofer individually. If you're not so limited on your placement of the subwoofer having to be behind the left or right main speakers in the system, a really good technique is to do something called the subwoofer crawl.

Now, this may sound a little bit strange, but it really works. The subwoofer crawl is simply a matter of taking your listening seat, either moving it or if you've got a large couch or something, placing the subwoofer as close as you can to the position where you're going to be sitting listening to the system.

Then, connect it up as usual and play some music or movies that have some good little frequency content in them. Now, what you're going to do, it sounds silly but it works, is get down on your knees and crawl around the perimeter, the outside edges of the room, listening for when the bass smooths out.

Now, subwoofers interact with rooms in a way that causes what are called, room nodes, which are peaks and valleys in the response. And these occur at different frequencies, depending on the room and where the subwoofer is placed. Now, these peaks and valleys mean that as you crawl around, you may find some spots where all of a sudden you have very, very loud bass, but it doesn't sound very smooth.

The flip side of that is that you may get into a position where you hear almost no bass at all, or very little. It doesn't sound very full in that position. And now in that position, you are going to be in a room null, where the output of the subwoofer is actually canceling with the size and dimensions of the room.

So, by doing the subwoofer crawl, you can easily listen for a spot that gives you the smoothest, low-frequency bass. And that now is a good position to try out by actually putting the subwoofer in that position, and now going back to your listening seat, sitting down and seeing whether or not that placement actually works.

It's a good, easy technique that doesn't require you to be technical, doesn't require a measurement equipment, and really works in most rooms. Let me know how you make out in the comments below!

One question we get a lot is about connecting your subwoofer.

Connecting a subwoofer is not very difficult, particularly as most home theater receivers have got dedicated subwoofer outputs on them.

The first thing that we should mention is before you make any connections to your system, it's a good idea to make sure that the power is off to the receiver and to the subwoofer. You're not necessarily going to damage anything, but it can cause some startling bangs and noises if things are not right.

Once that is done, go to the back of your home theater receiver or processor and locate the output labeled sub out. Most of the time you're going to find a common connection called an RCA connection.

On most receivers, there is going to be one sub output, on some there'll be two, but you're simply going to plug your RCA cable into that sub out on your receiver or processor, and then the other end is going to connect to your subwoofer.

Now, depending on what vintage of our subwoofer that you own, you may have a multi plug which requires a quarter phone to RCA adapter, which is included with the subwoofer. If you have one of those amplifiers, you simply plug the adapter in and then you plug the other end of your RCA cable from your receiver's sub out into that input connection, and now, the subwoofer is connected.

If you don't have one of these multi jacks on your subwoofer, you'll have just the standard RCA jack, and it's just a matter of plugging into the RCA that's labeled low level input. On some home theater processors, you're going to find a different connection as an option, which is called an XLR connection. It's typically found on higher-end equipment and it gives you the benefit of being able to run longer runs of these cables with lower noise and interference.

In the case that you've got an XLR subwoofer output on your processor, it's exactly the same as the RCA connection.

If you have a multi jack, it plugs into the same connector that held the RCA adapter, and if you have a version with a dedicated XLR input, it simply plugs into that input there.

In case you're not using a home theater receiver processor and have a stereo system or two channel system with an integrated amplifier or a dedicated preamp and amplifier, obviously, you're not going to find this dedicated subwoofer output in almost all cases with those electronics. So the question then is, how can you hook up your subwoofers?

In the case where you've got an amplifier that you need to hook up to the subwoofer, you're going to use what's called the high level connections, and these are identical to the speaker connections that you would use on a typical amplifier. Now, you have a couple of options here. You can either run your amplifier connections to the main speakers and then run another set of speaker cables to the subwoofer. Alternatively, you can either wire from the amplifier to the subwoofer and then jump off to your main speakers, or vice versa. You can go to the speakers from the amplifier and then from the main left and right speakers, you can jumper to the subwoofer. In any case, what you're going to be doing is you're simply going to connect both the left and right speaker outputs wherever they're coming from to the input of the subwoofer amp. And now, you have available the same signal that you would coming from a sub out on a processor. Now that you've got your subwoofer connected up in the manner that works with the electronics that you own, now is the time that you can power up your electronics, plug in the subwoofer, power it on, and then go towards making the adjustments and set up.

Questions? Comments? Let us know in the space below.

So when people use the term, blown, for speakers, it means that either something has been damaged or the speaker itself is no longer working because it's been overdriven which can be a result of mechanical stress. The woofers and the tweeters are moving too far, further than they're designed to move, or it can actually be due to heat burning out the voice coil wire.

At that point, one or all of the drivers will stop working completely but that's pretty obvious. So how do you know if something else is going on? All of a sudden you might hear a strange noise, it can be a rubbing sound that causes a crackling which can only occur on certain notes with certain music or it can occur all the time.

You might hear from a tweeter, for instance, you might hear a buzzing sound or a slight rattling sound. All of these things can be indications that something in the speaker has been overdriven. Now, a good question is how do you prevent this from happening? Well, your ears are a real good gauge of when the speaker is being overdriven, either the speaker is not happy or the amplifier driving it is not happy.

And it will sound very, very distorted, very harsh, very thin, very bright. That's an indication that you should probably turn things down, otherwise, you might cause damage to your speaker or to your amplifier. If you've experienced one of these issues where a drive unit in your speaker is not working or is making a strange noise that wasn't there before a party or before some incident, you can always call the company that made your loudspeakers.

It's very easy to replace them. In most cases, the connectors are push-on connectors for the wiring and if you can use a screwdriver, you can replace a part in your speakers.

The Design

M3 In Ceiling Speaker

One thing that's unique about our in-ceiling compared to many products on the market is the integrated back box.  We've already had customers ask "Why don't you just leave the back of the speaker open so that you can use the volume in the cavity where you mount the speaker?" There are a couple of issues with that from our perspective:

1. We don't know how big that cavity may be you're going to have behind it.
2. We don't know what kind of bass you're going to get out of that space.

Many Uses

Conventionally people used to think of in-ceiling speakers as products to be used for background music in hallways and kitchens, and certainly they can be used for that purpose: they're perfect for that sort of application. Typically in a home theater environment, in-ceiling speakers are also sometimes used for rear channels in place of a wall-mounted product (like our QS4 and QS8 surround speaker products.) But we're on the cusp of the new Dolby Atmos system.  

This system was developed a few years ago for commercial theaters.  It adds dedicated height-effects channels to the conventional 5.1, 7.2, or 10.2 systems that we're currently using for home theater. Atmos is a dedicated encoding and decoding format. You're going to start seeing more and more BluRay discs with Atmos encoding built into them in the future, there are over 100 movies in this format already. You will need a special receiver to do the encoding but it will be worth it. The height aspect is really something that has been missing in home theater systems as a whole. There will be options for you to upgrade your current system simply by buying a new receiver or a new processor and the addition of the in-ceiling speakers. You don’t have to change anything in your current home theater set up – you’re just going to be adding some more channels. The M3 In-Ceiling is perfect for that application.

Dolby recommends a minimum of 4 speakers. You can go down to 2 but they recommend four. If you have a really large room and you want the ultimate home theater experience, you can go up to 10 channels. We’re really looking forward to hearing your feedback when we launch this product, because we think it's going to be very well-received and perfect for this new Dolby Atmos system. Are you planning to take the next step in your home theater surround sound? Let us know in the comments below.

Hi, I'm Mike Rogers from Axiom Audio, and with this short tutorial, I'd like to show you how to check the phasing of your speaker and its importance.

Here, we're using Axiom Audio's bulk speaker wire. The logos on the speaker wire is designated as positive, and the opposite negative.

Whether you're hooking up to an input directly or using a banana plug, positive to red, negative to black.

Same goes for the input. Red to red, and black to black.

Using a nine-volt battery, the positive side, hook it to the positive side of the opposite end of your cabling.

Touch this a couple of times to the battery.

If the woofer goes out, it's in phase.

If the woofer goes in, this is out of phase, and you should check your cabling.

If all checks out, hook her up to the amp. Red to red, and black to black.

So now, your speakers are all in phase. Something you might like to try is listen to a track off one of your favorite CDs here with some bass.

Now, listen to that track, and then relisten to it with one of your speakers out of phase, and you might be surprised on how big of a difference and how important it is to have that phasing all in phase.

So I hope this video helped out. And until next time. Ciao. And don't forget to put that speaker back in phase.

Ian: I thought I'd start with just a bit of a history of how I was introduced to double-blind listening tests. It dates back to the early 80s when I first arrived at the National Research Council (NRC). They had a room set up there for the purpose of conducting double-blind research testing. They'd been doing it for quite a few years and gathering data on questions like

"Do people score sound the same way or does everybody have their own personal taste that is all over the map?"

Really, I think prior to that research at the NRC, most people did think that there were different flavours for different people: some of you may remember that there was the so-called West Coast Sound and East Coast Sound and British Sound and so on.

But really the research determined that that's not how sound works. People are overwhelmingly in agreement about how things sound: what's better, what's worse. Even people who swear they can't tell the difference in sound actually can tell the difference, down to some fairly minute detail.

And then you have the 'golden ears' - the people who make a career out of listening to things. They're great people, along with musicians, to have in these tests, because they can detail exactly what it is they're hearing and write that down so they can separate in great detail what aspect they are hearing that they liked or didn't like (or absolutely hated.) So a little bit of training or experience with instruments, and vocals, and sounds like that is of big benefit in these double-blind tests.

It was interesting - when I was first introduced to the double-blind test it was a real eye-opener. Prior to that we used to just build a product, and listen to it - we never thought about doing it blind. But there is no question in my mind the fact that there is visual bias and you cannot get around it. This comes down even to the point where we're taking measurements in the anechoic chamber and then we come to do listen tests in this room: if I know which is 'A' and which is 'B' - which speaker or which selection on the switch is which curve - there is absolutely no way that I can say "Okay, I'm going to put that aside for now and say that it doesn't matter." It does matter.

This was also proven at the NRC: if you took the blind screen away and did exactly the same test, the results varied enormously depending on whether the person thought 'the big one should be better' or 'that brand should be better'. So the idea of using a blind test is very important if you're going to use it for scientific research perspective.

I'm not suggesting anyone would want to listen blind themselves, but for the purpose of what we're doing it's a very important tool. Andrew has a lot of experience with double-blind testing as well, from the beginning of his career in the 90s at Audio Products International.

Andrew: Almost the entire time I've worked in this industry I've been introduced to blind listening tests. And of course when I joined Axiom five years ago, it was a very familiar aspect of what I was used to. I think it's very important to remember and consider that we use blind listening tests as a tool. It's a tool that is a part of the day-to-day tests we do in loudspeaker design - really, in any design. The reason for that is that we can't completely correlate all the measurements we are taking with what it's going to sound like.

Over the years you get an idea of exactly what measurements or what parts of measurements matter and are going to have a real impact to perceived sound quality. At the end of the day we can make all kinds of measurements, but until you sit down and listen to it and you bring that sort of subjective aspect to the design, there's no way to tell whether or not those measurements mean you've created a better product.

When we tend to do blind listening tests here, rarely (and it's actually fairly infrequent) we'll bring a competitor's product in to see how we stack up against a similar model or similar price in the marketplace. Really most of the blind listening that goes on here at Axiom is us looking at either a brand new model, or a new series version with our existing lineup.

Let's take an M80 for example: that product has existed since 1999 and it's been steadily improved with different versions - the Ti, v2, v3 and now we're at v4 - and the only way we can gauge the improvements that we are trying to make when we look towards a new version is by doing a blind listening test. Otherwise how to do we qualify that the new version actually performs better and sounds better than the current version? Obviously that's the only reason for making the version changes: we've learned something more about trying to correlate the measurements with what we hear, and really the blind listen test is confirmation of that.

Ian: When you're talking about something like the family of curves, it can be a collection of over 300 measurements depending on the speaker. We developed specific algorithms that we use to average these curves out. Our algorithms keep getting better and better with every year that goes by, and this creates a version change. We're up to version 4 in our current line. But the only way to prove that the algorithm is getting better is to subject the algorithm to a double-blind test.

In our listening room there are speakers and you pull an acoustically transparent cloth across them to do the listening from the seats across the room. If we're looking at something just in the family of curves, there will only be one speaker on each side - a right and a left - behind the screen, and we will change only the measurement of the speaker.

That's great because there is something called a position error: if you are doing a situation like this where you have two actual pairs of speakers you have to do the test twice. First you do it in the starting position, and then you have to switch the speakers to the other side so they're in their opposite positions, redo the test, and then average that data to get rid of the position error.

We tried a couple of times to create a switcher to actually move the speaker, but so far we haven't been able to do it fast enough, because you want almost instantaneous switching between A and B - it's much easier for people to be detailed in their critique if you do that. So we're still working on it. For now we simply redo the test and average out the two results.

So I think that's enough to start on subject of blind listening tests. We'll follow this up with a number of other videos. If there are questions or comments we'll try to include them in future videos. To summarize it's a very important tool in engineering. It's important to realize whatever test you're going to do sighted, you can also do blind, and also to realize it is an engineering tool and not necessarily something you want to do at home. It's complicated to set up and hard to do accurately at proper levels and so on.

In our next videos, we'll cover off the nuts and bolts of how to set up and perform a double-blind test, and the topic of distortion and why it is done with test tones in the chamber. Any other things you'd like to see covered?

Are we looking for a "faithful re-creation" of a musical event by our home stereo or surround systems, as if we were hearing it in the very concert hall or club or studio where it was recorded? Or a plausible illusion of musicians in our living room? Most of us would agree we're after a believable representation of a musical event, not a literal re-creation necessarily, with the appropriate directional and spatial cues and natural musical sounds that let us believe we might be hearing it live.

Fidelity

"High Fidelity" is an elusive term, because it raises the question of fidelity to what? In our quest for "hi-fi", the term that emerged in the 1950s to describe radical improvements in sound recording and reproduction, most of us would agree that we want musical instruments and voices to be accurately represented – to sound close to what we'd hear in real life. Loudspeakers should reproduce a trumpet and a piano so they sound like they do played in a room or club, and a female or male vocal should have the natural quality of a human voice.

The loudspeaker should encompass all the important harmonics, frequency range, and tonality of those instruments (the voice is an instrument) and not add its own tonal colorations to the mix. If all the links in the sound recording and home playback chain come together, then our ears and brain may be convinced that we just might be hearing a real piano, trumpet or vocalist across the room from our couch.

One microphone, one channel

Less than a century ago, analog technology limited a recording to one channel with one microphone. In fact, in the acoustical era of recording (before the advent of tube amplification and electrical recording in the mid-1920s), one huge horn into which a performer sang was connected to a diaphragm, whose vibrations moved a stylus that carved out analog groove undulations in a continuing spiral in a wax-coated zinc disc. (Playback in the home on Emile Berliner's gramophone was the reverse process: The undulations in the record groove moved the stylus, which was mechanically connected to a diaphragm at the apex of a big horn). There was no such thing as a "mix." During live recording, soloists or musicians stepped up close to the big horn to increase the recorded "volume" of the instrument relative to the rest of the band.

The entire recording and playback process was acoustical, obviously one channel, yet crowds in department stores marveled at the "lifelike re-creation" and power of the great American blues singer, Bessie Smith, the "empress of the blues," or of the famous Italian tenor Enrico Caruso's operatic voice, despite the fact that Caruso's and Smith's voices were almost obscured in a sea of surface noise, wobbly pitch and acoustical/mechanical distortions. Nevertheless it was a reproduction of a musical event, albeit primitive by today's standards, but one that sold millions of 78-rpm discs to a public hungry for recordings of great artists, to be replayed endlessly in their homes.

Stereo Recording and Playback

The arrival of stereo (2-channel) recording in the late 1950s brought with it real spatial and directional cues that conveyed the breadth of a musical ensemble as well as some spatial aspects of a recording venue. Going to two channels seemed logical enough – all humans possess two ears – and the recording and disc-cutting advances in the early 1960s let us finally appreciate the physical arrangement of musicians in an orchestra or band across a soundstage between the two stereo speakers.

Problems still remained in completing the illusion, of course. While two channels realistically conveyed the width of a musical group and, if microphones were carefully placed, some sense of depth, the actual reverberant cues that we hear mainly from the sides of a hall or club in real life were thrown at us from the front by the stereo speakers. That lessened the illusion of being at an event in a concert hall or club. Additions of artificial reverberation through side speakers were tried with some success in the 1970s but the 3-dimensional illusion of being transported from a living room to a larger acoustic space was still largely missing from two-channel recordings.

Direct and Reflected Sounds

Acoustical research into how our brain and ears interpret the arrival times and strength of sounds coming directly at us from the front and the secondary reflections from the sides suggested that more than two recording and playback channels would be necessary to supply the missing reverberant side reflections that would complete the illusion of real 3-dimensional hearing.

(The idea of multiple channels wasn't that new. As early as the 1930s, Bell Labs engineers had conducted live tests with the Philadelphia orchestra and concluded that three microphones and three playback channels across the front were the minimum to properly convey a reasonably realistic reproduction of the orchestral sound to a distant location – the tests were live, using three telephone lines, because there was no way at the time to simultaneously record three channels of sound.)

Multi-miking, Multiple Channels

Advances in tape recording in the 1960s that permitted four recording channels with four microphones allowed music producers and musicians to assign individual instruments or vocalists or groups of instruments to separate channels, and a recording engineer at a mixing console to adjust the relative levels, blend and contributions of each musician and singer. Multi-track machines proliferated with as many as 24 or more individual channels, enabling individual microphones and channels separately assigned to virtually every performer. Much of the actual creation of the recording happened later on in "the mix", when producers adjusted all the channel levels for balance and stereo placement across an imaginary soundstage. Classical music producers went overboard with multiple microphones, often using "highlight" mikes for weaker instruments that would be spotlighted (increased in volume) during the subsequent mixdown to two stereo channels. The result was often a well-balanced but 2-dimensional sound to the stereo presentation. (Lots of modern pop and rock studio recordings continue to be recorded and mixed this way and some aficionados view the results as "multiple mono" because the placement of individual instruments and singers, miked separately, is controlled by a "pan pot" that electrically places the musician at a specific point in the stereo soundstage.)

As listeners became more critical and desirous of spatial aspects missing from many recordings, new "purist" microphone techniques evolved, often utilizing three spaced omnidirectional microphones, a pair of crossed cardioid mikes, or a coincident stereo mike with adjustable capsules located about 15 feet above a band or orchestra. Sometimes an additional pair of mikes were positioned halfway back in a hall to pick up delayed ambient reflections.

The "minimalist miking" approach proved popular early on with engineer Bob Fine of Mercury Records, and later with audiophile labels like Telarc, Opus3, Reference Recordings, Bis, Chesky, Sheffield Lab, and Mapleshade. The resulting discs were (and still are) very popular with audio enthusiasts because they seem to have a natural spatial quality and a very direct unprocessed sound.

The placement of musicians occurs naturally in the stereo soundstage depending on their physical location relative to the microphones, adjusted before or during the recording session, and in most cases it can't be "fixed in the mix" later on with a pan pot.

Commercial Movie Sound

It was, however, the advances in commercial cinema sound's experiments with multi-channel recording/playback, first with six-track magnetic film, but later propelled in the 1980s by Dolby Labs development of Surround Sound that was the catalyst to more realistic recordings and soundtracks. Even with the early analog matrixed Dolby four-channel playback, it became clear that audiences loved the added realism that came with "surround sound" ambience directed to them from speakers on the side walls and rear of the theater. The third dialog channel was added at the front and digital recording and processing technology eventually yielded the ability to record and play six channels (Dolby Digital 5.1) in movie theaters, then in the home. The enhancement of spatial realism and directionality was undeniable, and it wasn't long before the recording and mixing techniques became popular with popular and classical record producers. While multi-channel DVD-Audio and SACD recordings proved to be a commercial non-starter for mainstream acceptance, critical listeners appreciated the heightened realism possible with multi-channel playback. Sophisticated decoding algorithms from Dolby (DPLII and its descendents), dts (Neo:6, etc.), and Lexicon (Logic7) proved to bring greatly enhanced realism when the spatial recovery was properly reproduced from side and rear surrounds.

Six or Eight or More?

With current elaborate multi-channel formats from Dolby and dts supported by Blu-ray enabling even more channels for height and other directional cues, the future seems limited only by production budgets and practical considerations in the home. Most listeners would acknowledge that six or eight channels (5.1 or 7.1) seem sufficient to supply most of the spatial and directional cues of our live music experiences or movie soundtracks.

Epic 80-500 7.1 Surround Speakers in Boston Cherry

Here at Axiom, in our ongoing program of loudspeaker development and double-blind listening tests, we're confident that our best loudspeakers are exceedingly neutral and accurate in realistically reproducing the sound of familiar (and exotic) instruments with no added tonal colorations. Played over the M80s, a well-recorded piano sounds uncannily like a real piano, and so do trumpets, trombones, French horns and male and female singers sound like the musicians or singers are in the living room (or you are in the concert hall or club, depending on the acoustic perspective of the recording). From my early days as a little kid in the 1950s listening to my dad's one-channel big corner-horn speaker system, the progression in playback realism to an Axiom 7.1 surround speaker system reproducing multi-channel music is enthralling and endlessly rewarding. Great music of all kinds beautifully reproduced in the home is one of the luxuries of modern life.

Now you know what it is . . . so what do you need? Click here to send an email to our audio experts for a recommendation based on your room size and listening preferences, or contact us toll-free at 1-888-352-9466 for fast, free, friendly advice.

Axiom Anechoic Chamber. Click Here to view the development.

Pictured above is the anechoic chamber—literally, a room with no echoes—at the National Research Council of Canada in Ottawa, Ontario. But it’s no ordinary room - lining all six walls of the chamber are large fiberglass wedges that absorb all reflections from the loudspeaker. Inside it is an Axiom M22 speaker, supported on a pedestal that can rotate to either side as well as tilt up and down. This is where the initial design and frequency response of the M22 (which has received glowing reviews from a variety of critics and reviewers), was refined, measured, and fine-tuned by its designer, Axiom founder Ian Colquhoun.

As you look at this picture, what may seem odd is why a loudspeaker meant to be listened to in normally furnished rooms would have its performance measured in a room that no-one would care to live in. The reason goes back to not only how we hear speakers in rooms, but also to a remarkable history of speaker measurement techniques and listening tests that took place in this scientific facility sponsored by the Canadian government.

Axiom Electronics Engineer Tom Cumberland adjusts the B & K Frequency Sweep Generator which feeds frequency response sweeps to loudspeakers during testing.

When we hear a speaker in a normal room, the sound that reaches our ears is made up of a multiplicity of direct and reflected sounds. Sounds travel at about 1 foot per millisecond, so when the speaker is reproducing music, some of the sound from the tweeters and woofers travels directly to our ears but a large proportion is also reflected from side walls, the floor, the ceiling and objects in the room. Those reflected sounds reach our ears a fraction of a second—a matter of milliseconds—after the direct sounds, and they’ll be different in every room, because of varying dimensions and distances and dissimilar furnishings. So the goal of putting a speaker in a chamber with no echoes is to find out exactly how much energy a speaker radiates when it’s unaffected by such reflections. (You could achieve the same result if you positioned the speaker on top of a tall pole in a quiet country field and measured it that way—far from traffic or urban sounds— and indeed Axiom designer Ian Colquhoun measures speakers that way before he flies to the NRC to do formal speaker measurements and listening tests.) When a speaker’s output directly in front of the speaker and at increasing angles to each side and above and below it is as smooth and as similar as possible, the designer can be reasonably certain it will sound fairly accurate in a normal room, because the reflected energy will have roughly the same tonal balance as the speaker’s direct energy on-axis.

Over the course of more than 20 years, the validity of these measurements has been confirmed by double-blind listening tests conducted in a nearby NRC listening room that approximates the size and furnishings of a typical living room. The program was guided by Dr. Floyd Toole, a Canadian physicist and psycho-acoustician who received his PhD in England in stereo localization, and continued his experiments at the National Research Council beginning in the 1970s. In his search for an accurate speaker with which to conduct his experiments, he discovered wild inconsistencies in speaker design and measurement, and an absence of controlled scientific research. Since he was already an audiophile, Toole invited several young Canadian speaker designers, including Axiom's Ian Colquhoun, to work with him in evolving new speaker measurements and listening tests (part of the NRC’s mandate was to assist Canadian firms in product development).

Toole gathered the results of these tests of frequency-response measurements and controlled listening tests by listeners with normal hearing and wrote scientific papers that were published in Audio Engineering Society (AES) Journals. The papers, "Listening Tests: Turning Opinion into Fact" and "Loudspeaker Measurements and Their Relationship to Listener Preferences," were unprecedented and Toole was later elected President of the Audio Engineering Society worldwide. The results of Toole’s research on speaker measurement and listening tests were startling and got lots of attention. The NRC program also had the willing participation of Canadian hi-fi magazines, editors and reviewers, beginning with AudioScene Canada and later, Sound & Vision Canada. The magazines needed a good facility to do controlled tests of a variety of Canadian, British, and American speakers for the magazine readers, and Toole’s program needed loudspeakers to experiment with. As a reviewer for AudioScene Canada, and later as editor of Sound & Vision (Canada), I was proud to be a member of the NRC listening panel for many years along with Floyd Toole, and Ian G. Masters (former editor of AudioScene Canada).

Debbie Swinton monitors different speaker measurement positions.
(Ian Colquhoun, Tom Cumberland and Axiom M80 pictured in the anechoic chamber).

Of course, sonic benefits accrued not just to Axiom’s speakers but to other prominent Canadian speaker builders as well. The findings of Toole’s program were in one sense startling and at the same time remarkably useful: When the brand name, size, type and price of speakers were concealed from listeners, persons with normal hearing agreed on which speakers sounded pleasing and accurate —"musical" if you will— and which ones were inaccurate and downright unpleasant. In the course of these tests, the notion of "golden-eared" listeners was largely dismissed. As long as listeners had a few hours of training on what to listen for ("fat" emphasized bass, strident harsh treble, muffled midrange, narrow "boxy" colorations and the like), they ranked good speakers and bad speakers the same way. And what was even more intriguing: If a speaker’s on-axis (in front) and off-axis frequency-response measurements could be kept as similar as possible, especially within a 15-degree "listening window" and especially over the midrange, the speaker would score highly in blind listening tests. While this is an oversimplification of decades of research at the NRC and by individual designers at Axiom and at other firms, it has proven to be extraordinarily predictive. Although no two speakers designed according to the NRC mantra ever sound exactly alike, there is nevertheless a remarkable congruence in what might be called "the Canadian sound," and that is one of openness, transparency, "linearity" (smoothness), and fidelity.

Related Links:
The National Research Council (NRC)
Anechoic Chamber (Wikipedia)

V4 brings improvements to a number of areas in our loudspeakers that have been developed and incorporated over the past three years, chiefly:

• Every crossover in the entire line has been modified to incorporate research discoveries made in the family of curves
• Most of the speaker drivers have been modified including a new tweeter across the line
• All drivers 5.25-inches and up will have a die-cast basket
• All the subwoofer amplifiers have undergone a redesign
• The in-wall speakers have gone through a total transformation: they now feature rigid stepped-style rear chambers and an upgraded flange that attaches to the wall
• The warranty is five years on all new products, and the Refurb store is two years

Our commitment to ongoing research in acoustical design means that we are constantly striving to find ways to bring you more realistic sound and a more life-like experience across our entire product line, stereo and home theater alike.

The newly redesigned 6.5-inch HP woofer, available in the new M100 flagship floorstanding speakers and LFR1100 omnidirectional speakers, as well as in the high-powered versions of the M60 and M80 floorstanding speakers and LFR660 and LFR880 omnidirectional speakers, has a larger voice coil, larger motor assembly, and larger roll surround, meaning there is more linear excursion capability. This means it can handle more amplifier power for clean, dynamic sound reproduction even at high volumes in large rooms without a subwoofer. Read more about the new high-powered woofer on our blog.

The new tweeter change, taking place across the entire product line, features a die-cast aluminum face plate for both better rigidity and for cooling. It functions as a heat sink for the tweeter. There is also a new horn design to provide smoother off-axis response above 12 kHz, and a larger rear chamber that lowers the resonance frequency further below the crossover region. The new tweeter can also handle significantly more power than the older version.

We have also made a number of changes to "Customize Yours" and the "Factory Outlet"

Customize Yours:

• Bi-wiring will become a no-charge option
• Custom Vinyl finishes will become a no-charge option
• Custom Grille colors will become a no-charge option
• Carpet spikes will become a no-charge option

Factory Outlet:

• Our factory seconds will no longer be sold in the Factory Outlet, they will move to their own spot in the Refurb Store.  Everything in the Factory Outlet will be new v4 product sold at a discount.
• Customize Yours will not be available in the Factory Outlet
• Factory Outlet speakers will have a 5-year warranty
• Speakers from the Outlet will take an additional 10 business days before shipping.

Our line has grown in leaps and bounds since the last update, and the changes to the site will help to bring some clarity to the options available for purchasing at Axiom Audio. As always, we are first and foremost about creating the most exciting listening experience we can: but we also want you to have lots of choices for finishes and accessories that suit your fancy.

It can be confusing, we know - how do you know which are the best speakers for home use? Are there characteristics about the best speakers for home stereo which are distinct from those that are best for home theater?

In a word, no! The best speakers for any use around your house will share the same key traits:

• The sound will be neutral - not 'warm' or 'mellow' or 'soft' - what you really want is 'accurate'. When a speaker is accurate, it won't matter whether you're listening to Brahm's "Hungarian Dances" or Bachman Turner Overdrive's "Takin' Care of Business" - with a neutral speaker both of them will shine.
• The speakers will be designed by someone who specializes in that business. If you are looking at the house brand speakers of a department store that also sells computer parts and napsacks, you may not be getting the quality you're looking for. Instead, search out companies with a history of research into speakers for home use so that you know you're getting the latest technological advances.
• The speakers won't be smaller than your fist. Sorry, a massive marketing budget is not an indicator of sound quality. There are laws of physics that dictate how big a speaker must be in order to recreate a concert or movie experience in your own home, and tiny cubes no bigger than an orange simply don't have the power or output you need to get a realistic experience.

So now that you're armed with these three simple rules, how do you go about choosing the best speakers for home?

May we suggest:

1. Browse through our stereo speakers to get a start for your home stereo or home theater speakers.
2. Read our articles on How to Buy Home Theaters - speakers, TVs, cables and more. Don't get fooled by slick salesmen - get educated and get the best value for your money!
3. Check out our guide to Building a Basement Home Theater if you're looking to create an incredible cinematic experience in your own home.
4. Ask us about the best speakers for home that will suit your needs. Our friendly audio experts are happy to answer your phone calls or emails and they'll work with you to get the system of your dreams.

Congratulations on your new Axiom speakers! If you're wondering how to paint speaker grilles, this is the place to find out!

Painting speaker grilles allows you to virtually hide speakers in plain sight.  Our in-wall, on-wall or in-wall/on-wall hybrid speakers all blend seamlessly into your decor when you paint them to match walls, cabinets or other elements in the room.

Let's get started!

Step 1:  Separate the grille, logo and frame. (click to enlarge images)

Step 2:  Prime and paint the frame first; set aside to dry.  You can use a brush for the frame.

Next, prime and paint the grille, using a paint sprayer to avoid paint build up in the grille holes.

If you prefer to use a paint roller, ensure it is a foam roller and get as much of the paint off the roller as possible before applying it to the grille and frame.  Three thin coats produce a much nicer finish than one thick coat.

Step 3: Allow to dry at least three hours, and preferably overnight.

Step 4:  When dry, carefully insert the frame into the mesh grille, taking care not to scratch.

Step 5:  Affix your Axiom logo, attach the grille to the speakers, and put on your favorite tunes.  You're done!

Not handy?  Or prefer a softer look?  In addition to our paintable speaker grilles, we offer six grille cloth colors through our Custom Shop. You can choose from white, black, charcoal, tan, gold, or burnt sienna cloth to match your home.

See more examples of rooms where customers paint speaker grilles to make them disappear into the decor.

By Axiom Forum Members

With the popularity of gaming systems like Xbox360 and PlayStation3 (PS3) and the sophisticated multi-channel soundtrack mixes attached to some of the games, we thought it was time for Axiom owners to rate the best-sounding games. Here are some Axiom forum members’ top contenders for best games on the best gaming speakers with candid comments attached, edited from the forums.

Dr. House (XBox 360; 5.1): “Gears of War 1/2, Call of Duty 4, Rainbow Six Vegas, Resident Evil 5, Halo 3, and Fallout 3 sound absolutely amazing and very realistic.”

StuntGibbon: “Flower, Frontline Fuels of War, BF: Bad Company, FEAR 2, Tomb Raider: Underworld, Resident Evil 5, Undertow (especially for LFE– low-frequency effects), and Legend of Spyro: Dawn of the Dragon (again, big LFE). If you're set up for home theater, you're ideally set up for most games. I prefer Guitar Hero and Rock Band in stereo, but Metal Gear Solid 4 sounds pretty great in 7.1. Call of Duty World at War does a great job as the sound renders to the environment directly in 3-D, so if you fire a weapon, you can hear that sound bounce around the environment, off buildings, etc. Chronicles of Riddick: Dark Athena also has really high quality sound.”

Jappy (Xbox360; 5.1 setup) –“Fallout 3. Sound is excellent and immersive. When I play it and something makes a noise in the distance coming from the surrounds, my cat gets spooked every time thinking there's something in the house!”

Ascension (PS3; 5.1 setup) – “Guitar Hero is just simply awesome on this setup! Gears of War 1 and 2 sounds fabulous and Killzone 2 sounds very realistic. It's funny how many of my friends and family want to come over just to play games on my setup.”

cb919 – “My son and I love playing Wipeout HD in 7.1.”

Murph (PS3) –“Some of the games have much better surround effects and LFE than the majority of movies produced today. A truly amazing experience.”

Terzaghi (XBox 360, PS3; Axiom Epic 80/500 5.1 system) –“You have a serious advantage when playing on-line shooters... you can definitely hear people creeping up behind you!

Got an opinion on the best games for the best gaming speakers? Weigh in on our message boards!

Hi-Fi Analog Amplifiers

Until quite recently, the majority of high-fidelity audio amplifiers were analog, and most were of a type called Class A/B. What does that mean? Perhaps one of the easiest ways to understand how an analog audio amplifier works is to think of it as a kind of servo-controlled “valve” (the latter is what the Brits call vacuum tubes) that regulates stored up energy from the wall outlet and then releases it in measured amounts to your loudspeakers.

The amount being discharged is synchronized to the rapid variations of the incoming audio signal. This weak AC signal is used to modulate a circuit that releases power (voltage and amperage) stored up by the big capacitors and transformer in the amplifier’s power supply, power that is discharged in a way that exactly parallels the tiny modulations of the incoming audio signal.

This signal in the amplifier’s input stage applies a varying conductivity to the output circuit’s transistors, which release power from the amplifier’s power supply to move your loudspeaker’s cones and domes. It’s almost as though you were rapidly turning on a faucet (you turning the faucet is the audio signal), which releases all the stored up water pressure—the water tower or reservoir are the storage capacitors-- in a particular pattern, a kind of liquid code. For our purposes, that’s all we need to know about analog amplification.

Digital Amplification

Basically, a digital (Class D) amplifier takes an incoming analog signal and converts it into a digital representation comprised of pulse widths. Although there are a number of different design variations, Class D amplifiers are essentially switching amplifiers or Pulse Width Modulator (PWM) designs. The incoming analog audio signal is used to modulate a very high frequency Pulse-Width Modulated (PWM) carrier that works the output stage either fully on or off. Later on, this ultra-high-frequency carrier must be removed from the audio output with a reconstruction filter so that no ultra-high frequency switching components remain to corrupt the audio signals.

Differences in Pulse-Width and Pulse-Code Modulation

A digital amplifier’s operation is a little like the way a CD or digital recorder works with PCM (Pulse Code Modulation), the basis of all digital audio-recorded media. In PCM digital recording (a CD, for instance), the digital sampling ADC (analog-to-digital converter) “describes” the incoming analog voltage and frequency with a digital code of ones and zeroes. But in a digital amplifier, the Pulse-Width Modulator describes a low-frequency audio signal as the “widths of a pulse” so many milliseconds wide. (A high frequency would be a narrower pulse, fewer milliseconds wide -- see diagram). Once the analog audio signal (the curving red sine wave overriding the pulses) is “described” in terms of pulse widths, it is amplified and then converted back to analog form. During that process, a reconstruction filter must remove all the on-and-off pulses, leaving only the lower frequencies that represent the audio signal.

As Axiom’s chief R&D engineer Tom Cumberland describes it, a digital amplifier is a “power DAC”, and of course a DAC (Digital-to-Analog Converter) is the basis of all digitally recorded media, whether we’re talking about CDs, hi-res audio, Blu-Ray soundtracks, DVD video, and so on. The view of some that “all digital amplifiers are crap” is not true. In fact, the clock rate of a good digital audio amplifier is typically in the range of 350 to 500 kHz (that’s 500,000 Hz). (Axiom’s ADA1500 digital amplifier uses a 450-kHz clock frequency.) By contrast, even the highest-resolution digital audio system (DVD-Audio and a variant used for Blu-ray soundtracks) runs at 192 kHz, which is far below the clock rate of a good digital amplifier.

Different Forms of Class D Amplification

Though we may think that “digital” means all the circuits in a digital amplifier work in on/off pulses, in fact there are a number of different types, including digital amplifiers that have analog elements.

A digital amplifier will have either analog or digital inputs. Good digital amplifiers with analog inputs can use analog feedback networks to lower the amplifier’s distortion, in much the same way that a Class A/B analog amplifier uses a negative feedback network to lessen the distortion. However, a digital amplifier that accepts only a digital input must rely on the incoming digital signal to lower distortion.

Feedback Networks

Why feedback networks? The reason they are used is that all parts in an amplifier have “tolerances,” which means that any particular part has a range or value in which it operates. Anyone who has examined such basic parts as resistors may have noticed they are specified as being “5%” or “10%” resistors, which means the specified resistor value is accurate within a range of 5% or 10%, respectively. Consequently, because of these variations in parts, a feedback network “looks at” the outgoing signal from the amplifiee -- the one that goes to your loudspeakers --and compares it to the incoming audio signal at the amplifier’s inputs. Any deviation in value away from the incoming signal is a distortion, so the negative feedback network applies inverse correction to compensate.

There are even differences in the operation of digital amplifiers. For example, the “ICE” digital amplifiers developed by the Ice Power division of Denmark’s Bang & Olufsen use a very complex negative feedback system due to parts tolerances. B&O holds patents on its “ICE” amplifier, which is basically a Class D switching design (Pulse Width Modulator) with variants that B&O claims reduces distortion to levels associated with Class A amps, while retaining the high efficiency of Class D switching designs.

“IR” (International Rectifier) is the system used by Axiom Audio in its ADA1500 digital amplifier. Axiom worked with International Rectifier to keep parts tolerances held to the very minimum amount, so that very little negative feedback would be used to correct for anomalies in the output. This approach also made the amplifier more robust in its operation without being subject to oscillations or instability.

Axiom and IR developed new silicon output devices that drive the MOSFETs in the output stage in such a way as to produce a perfect Pulse Width Modulated square wave at the output before the reconstruction filter.

Pros and Cons of ICE and IR Digital Amplifiers

One of the downsides to using a complex negative feedback network in a digital amplifier of the type used in ICE designs is a potential loss of efficiency. Performance may also suffer because of a slower clock rate.

In an IR type of digital design, which uses very little negative feedback or none at all, the clock rate is higher and efficiency increases. Moreover the high efficiency is combined with high power delivery and higher overall resolution. At full output, Axiom’s ADA1500 digital amp runs at about 95% efficiency (by comparison, class A/B analog amplifiers run between 50% and 60% efficiency; the remainder is wasted in heat).

The only requirements in remodelling home theater are some type of large-screen video system, which would include either a permanent or electric drop-down projection screen, typically with a diagonal measurement between 96 and 120 inches, some comfortable recliner seats or a couch or two, a 5.1- or 7.1-channel surround-sound home theater speaker system, and an audio-video (AV) surround-sound receiver to drive the five or seven speakers and subwoofer. A typical AV receiver like this Sherwood Newcastle R772 will usually have seven built-in amplifiers, one for each channel, and the ability to “decode” or sort out the Dolby Digital or dts multichannel soundtracks on DVDs, Blu-ray discs, and cable or satellite broadcast HDTV signals (Dolby Digital 5.1 is the audio standard for all HDTV programs). Depending on room size and budget, be sure to allocate from $500 to $1500 for an AV receiver with enough output power (100 watts per channel is ample for most rooms) to drive the home theater speaker system.

You’ll want to the big High-Definition video image in clarity and fidelity with a surround system of comparable quality. So if you spend $2000 to $3500 for the video projector and screen or an LCD or plasma display, then reserve about the same amount for a high-quality speaker like Axiom’s Epic 60/350 home theater surround system or the Epic 80/500 system. Such systems are highly capable in even quite large home theaters. Delivered to your home, these surround speaker systems sell for $2,415US and $2884US, respectively.

Depending on your budget for remodelling home theater, you can even forego a separate video projector and simply get a 50-inch to 65-inch LCD or plasma flat-panel display. The latter are much brighter than a front-projection system, which really only looks good in a totally darkened room.

Most homeowners install carpet on the floor, which aids in reducing potential sound reflections that may inhibit sound clarity. Let your budget dictate how many recliner chairs or couches to install, and whether or not you want to install risers, which elevate the rear rows of chairs for unobstructed viewing of the large screen video image.The ceiling will need to be high enough to accommodate the typical large screen with enough space above the screen to allow a dialog center-channel speaker like Axiom’s VP150 to be mounted above the screen (mounting it below also is an option). You may want to contemplate installing risers, to elevate the second or third rows so viewer’s sight lines are not obstructed, and you’ll need a tall enough ceiling so that when viewers stand up on the risers, they won’t hit their heads.

You don’t necessarily need or want windows, because if you are planning on putting in a front projector, the screen images from a projector always look their best in a totally darkened room. Projectors have to “throw” the image 12 to 15 feet (typically) onto a separate large screen, so the image is relatively dim compared to an LCD or plasma flat-screen display. That’s why renovating home theater almost always involves finishing a space in the house that often has few or no windows. If you do have windows, you will need blackout curtains if you are planning a large-screen front projection system.

While you’re renovating home theater, you will want the room to be large enough to put in two to three rows of comfortable lounger-type reclining chairs, with two or three chairs in each row. You will also need the room wide enough to permit installing powerful floor-standing speakers like the Axiom M80 v2 or M60 v2 to each side of the screen---and you don’t want to push the speakers into the corners of the room. Doing that may degrade sound quality by producing too much bass that’s “boomy” in character.

The ceiling will need to be high enough to accommodate the typical large screen with enough space above the screen to allow a dialog center-channel speaker like Axiom’s VP150 to be mounted above the screen (mounting it below also is an option). You may want to contemplate installing risers, to elevate the second or third rows so viewer’s sight lines are not obstructed, and you’ll need a tall enough ceiling so that when viewers stand up on the risers, they won’t hit their heads.

You have to find out if the amplifier is a Class A/B analog amp or a Class D digital amplifier before you can generalize about weight and amplifier quality. The appearance of high-quality digital amplifiers such as the Axiom ADA1500 has changed the equation. Digital Class D amplifiers are much more efficient (90% or more) than analog Class A/B amplifiers (about 50% efficient). As such, digital amps tend to run much cooler and therefore do not require the heavy heat sinks associated with high-powered analog amplifiers, hence the overall weight of a digital amp may not be a reliable indicator of its intrinsic quality. For instance, Axiom’s eight-channel digital ADA1500 has received superb reviews. And while it’s not exactly light (58 lbs), it still weighs much less than its multi-channel analog competitors whose output power is often about 200 watts per channel, yet typically weigh from 90 to 125 pounds. Moreover, as an 8-channel power amp, the ADA1500 is much more compact than many analog rivals, one of the great advantages of high-quality digital designs.

For conventional analog Class A/B amplifiers, weight can be an indicator of good, robust design because it suggests that the amplifier’s important internal components--the power transformer, heat sinks, and storage capacitors -- are large, and therefore have plenty of capacity to process and store large amounts of power to handle loud dynamic peaks without distortion.

By contrast, an analog amplifier that weighs less may use a smaller transformer with inadequate capacity and fewer or thinner heat sinks (heat sinks look like radiator fins and are used to dissipate output transistor heat generated by high power output and big dynamic swings).

2. Do Solid-State (Transistor) Amplifiers Sound Different?

They may sound different if they are used at high volume levels as they approach the limits of their output ratings, when the amplifiers’ distortion is rising and nearing the clipping point. However, if two different transistor amplifiers have the same smooth, linear frequency response, low distortion, and are operated within their output ratings, then they will tend to sound identical until they are called upon to produce great quantities of clean, unclipped power. With one amplifier, there may be a quality of effortlessness to the sound quality on big dynamic peaks in sound level, whereas another amplifier may start to sound strained or harsh on dynamic peaks because it cannot handle peaks free of distortion. Using music as a “test” signal, such differences may only appear as a need to “turn down the volume” rather than your hearing gross audible distortion artifacts. Note, too, that peaks can be as much as 12 dB louder, which will demand 16 times as much power from the amplifier, causing many lower-powered amplifiers or receivers to go into clipping.

3. How Does an Amplifier “Amplify”?

Perhaps one of the easiest ways to understand how an analog audio amplifier works is to think of it as a kind of servo-controlled “valve” (the latter is what the Brits call vacuum tubes) that regulates stored up energy from the wall outlet and then releases it in measured amounts to your loudspeakers. The amount being discharged is synchronized to the rapid variations of the incoming audio signal.

In effect, an analog amplifier is comprised of two separate circuits, one of which, the output circuit, generates an entirely new and powerful electrical output signal (for your speakers) based on the incoming audio signal. The latter is an AC signal of perhaps 1 volt that represents the rapidly varying waveforms of sounds (both their frequencies and amplitudes). This weak AC signal is used to modulate a circuit that releases power (voltage and amperage) stored up by the big capacitors and transformer in the amplifier’s power supply, power that is discharged in a way that exactly parallels the tiny modulations of the incoming audio signal. This signal in the amplifier’s input stage applies a varying conductivity to the output circuit’s transistors, which release power from the amplifier’s power supply to move your loudspeaker’s cones and domes. It’s almost as though you were rapidly turning on a faucet (you turning the faucet is the audio signal), which releases all the stored up water pressure—the water tower or reservoir are the storage capacitors

in a particular pattern, a kind of liquid code.

4. What Are the Different “Classes” of Amplifiers?

Class A designs have current constantly flowing through the output transistors even if there is no incoming audio signal, so the output transistors are always on. This type of amplifier has the lowest distortion of any but it’s extremely wasteful and inefficient, dissipating 80% of its power in heat with an efficiency of only 20%.

Class B amplifiers use output transistors that switch on and off, with one device amplifying the positive portion of the waveform, the other device the negative part. If there is no incoming audio signal, then no current flows through the output transistors. Consequently, Class B amplifiers are much more efficient (about 50% to 70%) than Class A designs, however there may be non-linear distortions that occur when one set of transistors switch off and the other set switches on.

Class A/B amplifiers combine the virtues of Class A and Class B designs by having one output device stay on a bit longer, while the other device takes over amplifying the other half of the audio waveform. In other words, there is a small current on at all times in the crossover portion of each output device, which eliminates the potential switching distortion of a pure Class B design. Efficiency of a Class A/B amp is still about 50%.

Class D amplifiers, although there are a number of different design variations, are essentially switching amplifiers or Pulse Width Modulator (PWM) designs. The incoming analog audio signal is used to modulate a very high frequency PWM carrier that works the output stage either fully on or off. This ultra-high frequency carrier must be removed from the audio output with a reconstruction filter so that no ultra-high frequency switching components remain to corrupt the audio signals. As previously mentioned, Class D designs are extremely efficient, typically in the range of 85% to 90% or more.

5. Do Amplifier Class Names Represent Performance Ratings?

No. Nor do the Class letters signify anything. They are just a convenient way of differentiating types of amplifier circuits. For example, “D” does not stand for “Digital” in a Class D amplifier, although there seems to be some conflicting evidence on this. In any case, in discussions, the “D” seems to have taken root as signifying a so-called “digital” design.

6. What Are “Digital” Amplifiers and How Are They Different From Analog Amplifiers?

An analog amplifier works in analogous fashion, regulating the output stage devices (transistors) to release power from the amplifier’s power supply to the loudspeakers in a manner that exactly mimics the tiny incoming audio waveform. Digital amplifiers use high-frequency switching circuitry to modulate the output devices.

7. Why Do Some Audiophiles Insist on Tube Amplifiers?

Tube amplifiers distort in a different manner from transistor amplifiers, generating musically agreeable even-order harmonic distortion that may lend a sense of so-called “warmth” to sound quality (the “warmth” is still a distortion or coloration; it’s not present in the source signal) and it’s this characteristic that most tube aficionados prefer. While tube amplifiers are often not as smooth or linear in frequency response as transistor designs and have other liabilities as well, when pushed near or past their output limits, tubes tend to gracefully distort, without the harshness associated with transistor clipping. However, tube amplifiers are limited in output power due to the tubes and output transformers.

Solid-state amplifiers, when pushed past their output limits, “clip” the audio waveform producing potentially harsh-sounding odd-order distortion that can be quite grating or unpleasant to the ear. On the other hand, kept below their maximum rated output, transistor amplifiers are very neutral and smooth and have none of the complex impedance interactions that may affect tube devices.

8. What Are the Most Important Attributes of Any Amplifier?

One primary attribute is a ruler-flat smooth frequency response from the deepest audible bass signals at 20 Hz (or lower) to the highest frequencies we can hear, at 20,000 Hz. A smooth, linear frequency response means that the amplifier will treat every incoming audio signal, whether it’s a bass-drum signal at 30 Hz or a cymbal’s high-frequency harmonics at 10,000 Hz exactly the same way, increasing the electrical strength of each tiny signal by exactly the same amount. Low total harmonic distortion (THD), below 0.5%, is essential so that any distortion artifacts remain inaudible with music. Finally, generous power output from a robust power supply so that the amplifier can handle the huge range of soft-to-loud dynamics present in virtually every type of music and soundtrack. “Generous” could be defined as a minimum of 50 to 100 watts per channel or more. For realistic music reproduction, more power is always desirable.

9. What Are “ICE” Amplifiers?

The Ice Power division of Denmark’s Bang & Olufsen (B&O) holds patents on its “ICE” amplifier, which is basically a Class D switching design (Pulse Width Modulator) with variants that B&O claims reduce distortion to levels associated with Class A amps, while retaining the high efficiency of Class D switching designs. ICE amps use a very high switching frequency of 384 kHz, which B&O says is 20 times as high as the highest frequency the ear can detect. The ICE amps also use feedback control to minimize the effects of the PWM design. Axiom’s engineering division took a different approach in the A1400-8 amplifier design. Axiom worked with International Rectifier to develop new silicon output devices and drive the MOSFETs in the output stage in such a way as to produce a perfect Pulse Width Modulated square wave at the output before the reconstruction filter. This approach also simplified the feedback network which made the amplifier more robust in its operation without being subject to oscillations or instability. The A1400-8 also uses a very high clock frequency (450 kHz) to allow for excellent transient response and non-aliasing in the audio band. The massive power supply is able to accurately output very high current and voltage to the loudspeaker over extended time periods.

10. How Do Small, Low-Powered Amplifiers Put Speakers at Risk?

Initially, it seems contradictory—how could a low-powered amplifier burn out speakers, when amplifiers of 200 or 400 watts per channel would seem to put speakers at much greater risk? The reason is that a small amplifier of 10 or 20 watts per channel can easily be driven into distortion and “clipping” with even moderately loud playback and dynamic peaks in loudness. The clipping cuts off the waveform and turns the output signal into an almost pure constant DC signal, which can quickly cause the fine wires in the speaker’s voice coils to overheat and melt. A large amplifier outputs clean power to the speakers –distortion-free AC audio signals—that the speaker voice coils will accept on a momentary basis without damage.

After reading this article, however, I think that you'll find the relative values of negative dB settings are actually logical, because in the old days, the settings on AV receiver volume controls were entirely arbitrary and unrelated to actual dB values. So whatever one manufacturer chose to put on the front-panel volume control or display applied only to that particular receiver. For example, one manufacturer might rate his volume control from 1 to 10, “1” being minimum volume and “10” being the maximum. Another might label the control going from 0 to 100.

History

A little bit of history helps to explain how the concept of 0 dB and its negative and positive values migrated from the professional broadcasting and recording environment to consumer audio gear. In the old days, Bell Labs and the broadcast networks came up with the concept of “0 VU” (which stands for Volume Units) to standardize electrical audio signal levels between interconnected radio and TV stations sending programming across the country over telephone lines to affiliate stations. The “0 VU” setting was standardized as a certain voltage into a particular impedance, and in a sense it reflected the perceived loudness of the incoming source signal (not quite the same as “0 dB,” but close enough for illustration). The use of the VU meter in broadcasting and recording was to ensure a strong enough audio signal that was well above any noise, yet prevent a too-loud signal that might distort or overload any recording equipment or the input circuits of the control consoles in the other radio stations. So long as the station engineers kept the incoming signal levels at or below the “0 VU” indication, they were likely to broadcast or record a nice clean undistorted signal.

0 VU in Recording

In analog tape recording, the 0 VU setting was viewed as the level beyond which the recorded signal might distort or overload the magnetic tape. In fact, 0 VU is 8 dB below a level of 3% harmonic distortion. With recorded peaks hitting 0 VU or slightly below, distortion was kept below 1%, which is generally inaudible with music or programming sources.Analog signals were nicely manageable because they behaved in an analog fashion: the louder the signal got, the greater the potential distortion and “saturation” of the tape. You could very occasionally let recorded peaks go a few dB “into the red” zone on the VU meter, because it was unlikely that the minimal distortion would be audible. The VU meter was a type of averaging meter that correlated with perceived loudness but wouldn’t register the peak instantaneous voltage of an audio waveform, so allowances for peak levels had to be built into your recording level settings.By contrast, with digital recording equipment everything stays pristine and clean as you approach 0 dB, and then BANG, at 0 dBFS (Full Scale) and above, you get gross distortion. Digital recorders have peak-reading LEDs or LCD bar-graph displays that actually register the peak voltage of the incoming audio signals, thus recording levels can be adjusted to never exceed the maximum of 0 dB. (In practice, with sloppy operators, they sometimes do, which accounts for some of the grungy sound quality of some modern digital recordings.)

0 dB on an AV Receiver

So how does all this relate to your AV receiver/preamp’s volume control settings? Think of “0 dB” on your AV receiver’s volume display as a kind of “maximum loudness” setting beyond which you may drive the amplifier into audible distortion or “clipping.” In the May AudioFile newsletter, I described the subjective sense of loudness changes that increases of 1 dB (just barely detectable change in loudness), 3 dB (slightly louder), or 10 dB (twice as loud) trigger in average listeners. On your AV receiver, the dB indications are still relative and you should hear them that way. If your AV receiver’s setting is at, say, -25 dB, and you turn it up to –22 dB, that 3-dB increase in loudness should sound “slightly louder.” Going from –25 dB to –15 dB, an increase of 10 dB, should sound about “twice as loud”. Keep in mind, however, that the relative loudness of your particular speakers and AV receiver settings won’t easily transfer to another listeners’ volume settings, especially if he has different loudspeakers that have different sensitivity ratings. Your listening distance and preferences also come into play. However, for Axiom enthusiasts who own the same model of loudspeakers or speakers with the same measured sensitivity, then the relative dB values on the AV receiver’s display will apply.

You can use your ears and the display readings on your AV receiver to experiment with small or large changes in loudness. With music, are you able to detect a 1-dB increase or decrease in loudness? If you listen really closely, you’ll likely be able to. It’s not easy or readily apparent with music playback, which is one of the reasons that casual comparisons of different loudspeakers or receivers are so flawed. If the playback volume isn’t exactly equal, then you may feel that one speaker or receiver sounds “better” than the other, when in fact one may simply be 1 dB louder than the other. And much of the time, you won’t “hear” the slightly louder one as being louder; you’ll just sense that somehow it seems more pleasing. Once you precisely adjust the playback levels with pink noise and a Sound Pressure Meter, many alleged differences you thought you were hearing disappear. Credit the decibel and a Sound Leve

One of the most difficult-to-understand terms for newcomers (and even experienced enthusiasts) in audio and sound reproduction is the decibel, partly because it’s a measure of relative intensity or power in both acoustics and electrical circuits. It may help to understand it better if you know how the engineers at Bell Laboratories, back in 1924, came up with the term from which the decibel was derived.

One “Bel,” named in honor of the brilliant inventor and communications pioneer Alexander Graham Bell, represented the relative reduction in audio level that a mile of telephone cable imposed on the telephone audio signal (and you were worried about 30 or 40 feet of speaker cable!). It became shortened to “decibel”, which represents one-tenth of 1 bel (1 bel = 10 decibels). So a decibel expresses relative intensity, and it’s logarithmic in nature, based on multiples of 10. In terms of loudness and acoustical intensity, the decibel can conveniently express a huge range in sound pressures to which the ear responds (far greater than one million), from 0 dB (the threshold of hearing in young, undamaged ears) to 120 dB, the loudness of a jet engine or front-row seating at a rock concert. An increase of 1 dB can also be thought of as a just barely noticeable change in loudness, or the sound intensity generated by a mosquito flying at a distance of about 3 meters, or 10 feet. Can you hear a mosquito in a quiet cabin flying 10 feet away? Young, undamaged ears likely can.

On a more practical level, we often wonder how amplifier power output in watts relates to changes in the acoustical output (loudness), of loudspeakers. Now for the really amazing part: although it seems that doubling the amplifier power in watts would also double the loudness, disappointingly it only increases loudness by 3 dB, a change in volume most of us perceive as “slightly louder.” That’s why going from an amplifier of 75 watts output to one of 150 watts output only increases the actual acoustic output a bit—again by 3 dB. To make sounds subjectively “twice as loud”—an increase of 10 dB—requires ten times as much power from the amplifier. So if your speakers are using 5 to 10 watts (a fairly typical value) to produce reasonably loud sound in your average-size room, and you want to make your music twice as loud, you’ll need ten times as much power, or about 50 to 100 watts. That’s why it’s important to have plenty of reserve power in your amplifier/receiver to handle the peaks in loudness that may be at least 10 dB louder than average levels. In fact, I have a classical CD recording where the loudest portions of the music are almost 30 dB louder than the quietest passages. Think about how much amplifier power that requires cleanly reproducing the 98-dB peaks in my 2,200 cu. ft. living room. Bring on the Axiom ADA1500-8!

Most of us have seen the charts that document the relative loudness of various common sounds—rustling leaves, 10 dB; a very quiet library, 30 dB; average conversation, 60 dB; street traffic, 85 dB, a full orchestra, 98 dB, and so on. But it’s fun to actually measure the relative loudness of various types of music heard live; moreover, it’s amazing how accurate even an inexpensive sound pressure meter is, and how closely the values relate to our subjective perception of “quiet” and “quite loud” music and to universally measured sound pressure levels.

A practical illustration of real-life volume levels of two acoustic instruments occurred at a violin and piano recital I attended by a young virtuoso violinist, Yuri Cho, and her accompanist, Michael Tan, at Merkin Concert Hall, a small 300-seat venue in New York City. Mr. Tan played a big Steinway concert grand piano. Ms. Cho was standing about 5 feet in front of the piano. I sat in Row B, only about 15 feet from the two performers. In the background hush before the recital began, I could easily hear the whirr of the hall’s air-exchange system, which was constant and measured 55 dB (all C-weighted), the latter quite high compared to some of the newest halls with baffled air-exchange systems that are almost silent at 35 or 40 dB. With my RadioShack meter in my lap, during the pianissimo sections, where the two recitalists played very quietly, the sound levels averaged about 70 dB; when things got loud (forte), the measurements rose to peaks of 87 and 89 dB, which certainly sounded very loud.

The higher strings of Ms. Cho’s violin had a somewhat hard and steely edge from my seat in Row B, so after intermission I moved to row F, which about doubled the listening distance from the piano and violin to 30 feet. According to acoustical laws (the inverse square ratio) the sound levels should have dropped to one quarter of their previous values (in an anechoic chamber that would happen) but in the hall, sitting midway back in Row F, my ears were receiving a much more rounded blend of direct and reflected sounds. Amazingly, the measured levels were only slightly less loud. On dynamic peaks in Gershwin’s wonderful Three Preludes, the sound levels still peaked in the range of 85 dB, only about 3 dB less loud than sitting up close. In Row B, the direct instrumental sounds were very dominant, with very little ambience, which is why the violin sounded hard (yes, some real instruments can sound harsh and edgy close up; I ought to know, I studied violin for 15 years). Back in row F, my ears were receiving lots of reflected sounds from the hall’s side walls, which combined with the direct sounds to produce a much more pleasing blend, with hints of the small recital hall size. 

Next month, we’ll examine the “0 dB” indication on lots of AV receiver volume controls, and how that relates to actual sound levels in your listening room.

Now that the Blu-ray/HD-DVD conflict over competing high-definition disc formats is settled, it’s time to take a detailed look at the admittedly confusing assortment of high-quality audio soundtrack options that Blu-ray discs and players will output, as well as which combination of cables, components and connections you’ll need in order to benefit from the available high-quality audio options.

In the old days, it was pretty simple: first Stereo, then Dolby Surround, followed by Dolby Pro Logic, then Dolby Digital 5.1, with DTS tagging along as an optional but oft-included soundtrack on many DVDs.

As soundtrack performance progressed, our budget and inclination to upgrade expanded as well, so we could take advantage of the improved audio standards. One of this hobby’s many delights is the ongoing enhancement of our audio-video sources, with its ever-present process of upgrading, even when some of the ballyhooed advances may not be as dramatic as some of the manufacturers and marketers would have us believe. Still, engineering never stands still, so to heck with the expense and onward and upward with greater audio and video fidelity!

Background

The standard DVDs you own now all use “lossy” multi-channel soundtracks, developed by Dolby Labs and Digital Theater Systems (DTS). “Lossy” means that a lot of data are thrown away using perceptual coding in order to greatly reduce the amount of “digital” space occupied on the disc by the soundtracks. The perceptual coding is very sophisticated (it’s based on the principle that sounds softer than you can detect in the presence of louder sounds at or near the same frequency do not need to be encoded). This process enables Dolby Digital and DTS to carry six-channel discrete soundtracks (five channels plus a “.1” low-frequency effects channel), which run at relatively low data rates even when compared to the data rate from a lossless two-channel format like Compact Disc’s “Red Book” PCM (pulse-code modulation).

While lossy formats like Dolby Digital 5.1 and dts can--and do--sound really excellent, far better than the old analog soundtracks of the past, anyone would agree that lossless soundtracks such as those offered on Blu-ray are preferable if enough space is available on the disc. Just to emphasize, a PCM audio track like that from a compact disc is lossless: it’s a stream of “1s” and “0s” that precisely describe the frequencies and relative loudness (amplitude) of a music signal. No data are discarded to conserve bandwidth. And Blu-ray’s new lossless soundtracks use sampling rates and word lengths greater than compact disc and have the considerable potential to sound superior to the existing lossy Dolby Digital/dts formats.

The Blu-ray Soundtracks

The three lossless audio formats associated with Blu-ray players’ high-resolution audio soundtracks are Dolby TrueHD, DTS-HD Master Audio (MA) and Linear PCM (Linear Pulse-Code Modulation). These formats will all convey eight discrete channels (7.1) of no-loss audio that exactly duplicate the original studio masters, but there are various ways of extracting the signals depending on how new or current your AV receiver is and what kind of input connections are available.

Older AV receivers

Owners of AV receivers that have a set of multi-channel analog input jacks—usually six or eight RCA female inputs—need not despair. As long as you get a Blu-ray player which has internal decoding of the aforementioned formats and that’s equipped with a full set of analog output jacks, then you can still connect and benefit from the impressive high-resolution audio included on most Blu-ray discs. Your AV receiver doesn’t need HDMI inputs or outputs as you can still route the 1080p video directly over HDMI cables to your TV display or projector, bypassing your AV receiver for Blu-ray video. You will require a set of six or eight analog RCA cables to link the Blu-ray player’s analog RCA audio output jacks to your AV receiver’s multi-channel analog input set.

If you don’t care or don’t want to be bothered connecting the analog eight-cable set, then you could still use an optical digital or coaxial digital output from the Blu-ray player to the AV receiver’s optical or coaxial input. Your AV receiver will extract a standard lossy Dolby Digital 5.1 mix from the Blu-ray disc’s Dolby Digital Plus soundtrack. The latter is a lossy audio format, so you can expect the audio to sound as good as any standard DVD’s Dolby Digital mix or maybe better, because Dolby Digital Plus runs at a higher data rate that your AV receiver’s chip set may benefit from.

Getting Lossless Audio via HDMI and PCM

Dolby TrueHD is based on the original Meridian Lossless Packing profile that was developed for DVD-Audio, in which eight channels are compressed to take up less space but then exactly reconstructed by the player so there are no losses. If you get a Blu-ray player that will “unpack” or decode Dolby TrueHD and output it via HDMI in PCM form, then you all you need is an AV receiver that’s capable of receiving multi-channel PCM via HDMI. Any version of HDMI cable will carry multi-channel PCM--- including HDMI 1.0 through HDMI 1.3. However, your AV receiver must be able to deal with eight channels of PCM audio via HDMI connection.

The other method of extracting and hearing Dolby TrueHD is by what’s known as bitstreaming: a raw data stream of Dolby TrueHD that is sent from the Blu-ray player via HDMI 1.3 to an AV receiver that has built-in decoding of Dolby TrueHD. So far, there are only a few AV receivers with this capability, however more and more will be appearing with each passing month.

DTS-HD Master Audio

Similar to Dolby TrueHD, the same requirements exist for extracting the DTS-HD lossless Master Audio tracks, which like Dolby TrueHD, can carry up to eight discrete audio channels. You must have a Blu-ray player that will internally decode DTS-HD MA or output it via a bitstream and HDMI 1.3 to a new AV receiver that has a built-in decoder for DTS Master Audio.

How Much Better Will Dolby TrueHD and DTS-HD MA Sound?

I can’t say with certainty how much better the advanced lossless soundtracks will sound compared to existing Dolby Digital or dts 5.1. What I can say is that they will sound at least as good as DVD-Audio and SACD multi-channel recordings or your best-engineered CDs, if we’re talking two channels. The best of DVD-A and SACD recordings are spectacular, as good as audio sources are likely to get in the next decade or so, and the same lossless traits characterize the new high-rez audio soundtracks from Blu-ray.

As careful listening comparisons have shown, the multi-channel aspect of music and soundtrack reproduction increases realism by a substantial margin over 2-channel stereo. The potential to reproduce studio master tape quality for all the channels of a movie or concert in your home is an enormous luxury that could barely be envisioned in decades past. Even now, I recall the first demonstration of a digital stereo recording at a meeting of the Toronto Audio Engineering Society more than 25 years ago, and what a huge audio liberation it seemed to me at the time. I say “liberation” because it seemed immediately evident to my ears that the digital music recording of a piano and singer freed stereo reproduction from the constraints of background noise, flutter, audible distortion and the severely compressed dynamics that, to a greater or lesser degree, characterized all analog recordings up until then. Now it’s up to the loudspeaker, subwoofer and amplifier manufacturers to design equipment that will accurately reproduce everything present on the Dolby TrueHD, DTS Master Audio and PCM soundtracks—and it would be immodest of me to point out where Axiom lies on that continuum! – A.L.

You've seen references to "impedance" and "ohms" in various loudspeaker specifications or in your owner's manual for an AV receiver. But what is it? Do you have to "match" speaker impedance to your AV receiver or amplifier?

Let's first get a couple of things clear: Impedance has nothing—I repeat, nothing—to do with sound quality. It is an electrical measurement of a loudspeaker's resistance; its opposition to the flow of electric current (the audio signals) from your AV receiver or amplifier through your speaker cables to the speaker drivers and the fine wire in the driver voice coils. It's a kind of electrical "friction" to the movement of electrons through the copper wires in your speakers. We measure impedance in "ohms," named after George Ohm, the German physicist.

In a loudspeaker, current does all the work; voltage is the "push" behind the current, kind of similar to the way water pressure (voltage) forces the water (current) through a hose. If you have a narrow hose (a high impedance), not as much water (current) flows. Use a larger diameter hose (lower resistance) and more water (current) flows.

Current has to flow through your loudspeakers, but we certainly don't want them or the speaker cables to heat up and waste all your amplifier power! We want the electric audio signals to drive the speakers to produce great sound.

Loudspeakers have impedances of 8 ohms, 6 ohms or 4 ohms (those are "nominal" or approximate values, because the impedance of a speaker changes all the time with the different frequencies of music). A 4-ohm speaker draws more electric current through your AV receiver's output transistors, and since more current equals greater power, 4-ohm speakers tend to have greater dynamic range and play louder more easily than 8-ohm speakers.

AV receivers also produce more power into 4-ohm speakers than 8-ohm speakers, as much as 50% more. There isn't any way you can lower the impedance of your speakers--that's set by the designer and the voice coil windings and crossover parts, but you can check the impedance of any speaker by looking at the identification plate on the speaker's rear panel, where its impedance will be stated in ohms.

Your AV receiver has essentially zero output impedance (0 ohms) so you do not have to match the impedance of your amplifier to the speakers. The amplifier does not expect to "see" speakers of given impedance and you can connect speakers with different impedances (8 ohms, 6 ohms, 4 ohms) to an AV receiver with no negative effects so long as the impedance of any of your speakers doesn't go below 4 ohms. If speaker impedance is too low, too much current will run through the AV receiver's output transistors, causing the receiver to overheat and shut down. If you get 4-ohm speakers, make sure your AV receiver is able to drive them easily without overheating. Some brands of AV receivers have no problems driving 4-ohm speakers, others cannot.

Finally, you do not want your speaker cables to raise impedance or resistance and waste your AV receiver's power on its way to your speakers. So use 12-gauge speaker cables between your AV receiver and any loudspeakers and you won't have problems of increased resistance. You can run 12-gauge speaker cable to lengths of 50 feet or more without problems.

Assuming competently designed subwoofers (not white van “one-note subs”), I believe that all such impressions of "tight" or "flabby" bass are almost entirely the product of crossover points, room placement, listener location and room standing waves and room modes — plus the listener's active imagination. Added to this are the casual listening comparisons made of subwoofers, with no scientific controls in place. It hasn't helped that a lot of subjective reviewers in certain magazines and web sites talk about this without understanding the fundamentals of bass frequencies and room effects, or how to do careful appraisals of subwoofers. Moreover, deep bass is not intrinsically "tight." The wavelengths are long and quite slow compared to midrange and high frequencies. In fact, the woofer cone movement is very slow compared to upper bass and higher frequencies.

But don't take my word for it - you can prove it for yourself. Try playing only your subwoofer with no accompanying upper bass and midrange frequencies. Turn off all the speakers except the sub. There's nothing "tight" or musical sounding about what issues from the subwoofer—unless of course the crossover is not engaged or there isn't a steep enough roll-off.

That’s because the midrange and upper bass transients supply the “tightness”—the initial plucking of a stand-up bass string, for example. The "pluck" or snap of the string is hundreds of Hz higher than the fundamental energy, which is often in the region of 30 Hz to 100 Hz. Similarly, the initial “thwack” of an orchestral bass drum is in the lower midrange; so are the sounds of the percussionist’s mallets connecting with the stretched diaphragm of tympani drums.

Another experiment you can do to understand the natural reverberance of bass is to actually try hearing a plucked or bowed double-bass viol or cello, or even an electric bass guitar, in your own room. Some reviewers I've read seem never to have had this experience. I have had the good fortune to experience it first hand: my mother led a small chamber orchestra that practiced in the music room of the house I grew up in and that included a big double bass and a cello. A good friend of mine in Toronto is a professional double bassist, and when you hear that bass plucked or bowed in a domestic room, the whole room—the entire house— is suffused with bass; it lingers and reverberates. It's wonderful and astonishingly powerful. So is a real cello played in the confines of a typical living room. Words like "tightness" or "flabbiness" simply don't apply.

Try and think of subwoofers simply as low-frequency air pumps, supplying the long wavelengths of the deepest bass fundamental tones. You simply want enough power to move enough air—to fill a particular room at a level that yields a plausible illusion of the real instruments, so choose the appropriate sub that will do that, and use excellent satellite speakers, such as the M80s, M60s or even good bookshelf models like the M22s, M3s and M2s to supply the elusive “tightness” that audiophiles seem to believe exists. As long as the satellite speakers, whether floor-standing or compact bookshelf models, have smooth midrange and reasonably linear upper bass response to 100 Hz, then they’ll generate all the tightness that’s present. Of course a very powerful amp capable of properly reproducing these upper bass peaks will also add dramatically to the experience.

For example, there is nothing "musical" or "unmusical" about the EP175, the EP350, EP400, EP500, or EP600. The "tight" musical qualities are supplied by the M80s or M60s; the subs just pump out the low-frequency energy. If you place the subwoofer with reasonable care, and match them well in terms of the crossover with your main speakers, any of them will supply the "tightness" and "snap" that you're searching for.

Sensing that I might be pilloried by some high-end reviewers for challenging the dearly held notions of tight or loose bass, I asked several of my Axiom colleagues, for their engineering comments. While acknowledging and endorsing my analysis, they commented:

(Tom Cumberland, electrical engineer): “If there is ‘tightness’ to subwoofers, it applies to the driver and amplifier combination. If the woofer is not well-controlled, it could be categorized as ‘loose.’ Since at Axiom we design and manufacture both our own amplifiers and our own woofers we have total control over all the variables."

(Ian Colquhoun, chief designer and president of Axiom): “The reality is that a lot of the impression of tightness from a subwoofer is just in the crossover roll-off. If you have an adjustable crossover on your sub you can do this experiment by comparing the lowest crossover setting to the highest and see the impression of “tightness” go up with the frequency setting. Because of this phenomenon, an EP175 can, on its own, sound so-called “tighter” than an EP600, but this is because it does not have the sophisticated crossover that is in an EP600. Consequently the EP175 is playing (at a lower levels, mind you) those mid-bass frequencies that contribute to so-called impressions of "tightness." The EP600, on the other hand, has a brick-wall filter that does not allow any mid-bass frequencies to emanate from the subwoofer. If you really want “tight” bass, then you need to concentrate on the main speakers and amplifier combination because that is where those mid-bass frequencies are and should be generated. An A1400 amplifier and a pair of M80s will deliver the tightness you are looking for.”

A. Developed by Hitachi, Panasonic, Sony, Toshiba, Philips, Thomson and Silicon Image, the High Definition Multimedia Interface (HDMI) is a compact 19-pin plug (about 30% larger than a USB connector) and cable for connecting High-Definition video and multi-channel audio-capable components (HDTVs, HD-DVD and Blu-ray players, HD camcorders and so on) as well as helping to speed the convergence of computer and consumer AV products.

2. Q. How is it different from the component video cables that I use between my current DVD player, AV receiver and TV set?

It differs in two important ways: Your three component video cables carry the High-Definition video (or standard-def video) in analog form. While component video is technically capable of carrying a 1080p signal, the copy-protection schemes won’t allow it. HDMI is a digital interconnect, hence it carries the hi-def video signals in uncompressed digital form. This avoids two conversions of the video signal from digital to analog and back to digital again, thereby eliminating potential image losses that may occur in the two digital-to-analog conversions that take place. Even though HDMI is an all-digital connection, there is still a conversion that takes place in the display.

There’s another big advantage of an HDMI link: it combines the digital video with multi-channel digital uncompressed audio — up to 8 channels — into a single connecting cable. (HDMI also replaces an older digital cable standard called DVI, which, although it carried digital video, did not have the multi-channel digital audio capacity of HDMI on a single cable.) Incidentally, “uncompressed” means there are no losses in the digital audio, i.e. no data is thrown away in order to “fit” the signals into a certain format like a Toslink optical or digital coaxial connector. For example, existing Dolby Digital (or dts) 5.1-channel digital soundtracks are “lossy” – some data is ignored in order to squeeze six channels of sound onto a regular DVD soundtrack and output it over a single digital coaxial or optical cable.

3. Q. OK, so what’s the big advantage? Dolby Digital 5.1 sounds pretty good to me.

A. Dolby Digital 5.1 is very good (so is dts), but both are lossy,as mentioned above. In losing that data, the sound may become a little coarser. By contrast, CD (remember that?) is a lossless format: no data is thrown away in the linear PCM (Pulse Code Modulation) bitstream that comprises CD sound, which is why it sounds so excellent (assuming a good recording). In comparison, MP3 is a lossy—very lossy—format, which also explains why slower-running versions of MP3 sound so crummy.

4. Q. There’s been talk of different versions of HDMI and possible incompatibilities.

A. OK, let’s get this straight: There have been four versions (plus several a and b variants) of HDMI-- but each one uses the same 19-pin cable and plug! The latest HDMI standard is 1.3; the first was HDMI 1.0. As the original standard evolved from HDMI 1.0 through 1.1, 1.2, and now 1.3, the cable and plug remained identical. The only things that changed were increased capacity and versatility in some areas.

For instance, all versions of HDMI will carry1080p HDTV signals as well as 8 channels of digital audio at 192 kHz/24-bit resolution. In fact, if you purchased a new “1080p” high-def display, that means it’s capable of displaying an image of 1920 x 1080p (1,980 pixels across each of 1080 progressively scanned lines) and you must use an HDMI cable to deliver that resolution from an HD-DVD or Blu-ray hi-def disc player. If you use the component video outputs on those players, the resolution will be limited to 480p, the same as standard DVD, because the Hollywood guys do not want you making perfect digital copies of their copyrighted movies.

5. Q. So what are some of the other features of “increased capacity and versatility” that you mention are part of newer HDMI versions?

A. One really neat feature is an “Auto lip-sync” ability that enables an HDTV that is HDMI 1.3-capable to automatically correct any out-of-sync video and audio—so called “latency” that may occur in some HDTV sets because the complex video processing slows down the video signal relative to the audio causing the sound to arrive before the actors’ lips move. This can be really irritating for some viewers (myself included). HDMI 1.3-capable HD sets will automatically correct out-of-sync dialog. Keep in mind that if you want this and other features, the source components (Blu-ray or HD-DVD) plus your AV receiver and HDTV display must all be HDMI 1.3-compliant.

6. Q. What about the nightmare stories I’ve heard about HDMI not working with some HDTV sets or other components?

A. It all relates to HDCP—High definition Digital Content Protection, the digital anti-piracy scheme that keeps you from ripping off Hollywood. Whatever devices you want to connect with an HDMI cable and ensure that you’re going to see a high-rez picture and enjoy high-quality sound must be “HDCP compliant.” So look for that phrase in any features or specifications listed about the TV display, the AV receiver, and the video player, be it a DVD, HD-DVD or a Blu-ray machine. “HDCP compliant” indicates that the HDTV set and the other components will communicate with each other and check to ensure that all include the HDCP anti-piracy codes. If one of the components is not HDCP-compliant, then it won’t pass the HDMI signals and you won’t see or hear anything.

7. Q. So what are the new digital multi-channel surround sound formats that HDMI will carry?

A. HDMI 1.3, the latest version, will carry Dolby True HD bitstreams as well as DTS-HD Master Audio, both of which are lossless digital audio formats developed for the soundtracks of HD-DVD and Blu-ray discs. These will be decoded by a new generation of AV receivers appearing this fall. HDMI 1.3 will also carry Dolby Digital Plus (DD+), a much-improved lossy compression system that runs at 6.1 megabits per second, a huge improvement over conventional Dolby Digital 5.1, which runs at just 0.64 megabits per second. DD+ can convey up to 13 channels of sound compared to Dolby Digital’s 5.1 channels. The data rate of DD+ is so fast that like Dolby True HD and DTS-HD Master Audio, only HDMI 1.3 will carry it.   

8. Q. My present AV Receiver has only Dolby Digital 5.1 and dts. Will I have to replace it with a new AV receiver to hear the benefits of these new digital soundtracks?

A. No, not necessarily. Many new HD-DVD and Blu-ray players have built-in decoders that will output the new multi-channel audio formats over HDMI as 8 channels of linear PCM 192 kHz/24-bit uncompressed digital audio, so if your AV receiver or AV preamp will handle a multi-channel PCM signal and is HDMI-compliant, then you’ll be fine. In other words, if the HD-DVD or Blu-ray player will internally decode the new sound formats and output them as 8-channel linear PCM, then any HDMI connector will carry that multi-channel signal. HDMI version 1.3 is only necessary if you plan to have a new AV receiver with built-in decoding of Dolby True HD or DTS Master Audio. Note also that all versions of HDMI will carry existing Dolby Digital 5.1 and DTS compressed bitstreams as well.

9. Q. My HDTV is a 720p model. If I use the new HDMI 1.3 connector, will it deliver 1080p to my HDTV display so I can see the improved clarity?

A. No. You could use the HDMI 1.3 connector or earlier versions of HDMI but the native resolution of your HDTV is 720p, which limits its maximum resolution to that figure. Even if you connect a Blu-ray or HD-DVD player outputting 1080p, your TV will scale (convert) it to 720p. Your set cannot display greater resolution than its “native” display.

You’d have to purchase a new 1080p HDTV to see the improved clarity that 1080p can yield. Note however that all HDMI cables will carry 1080p and all lower resolutions of video—1080i, 720p, 480p and 480i. However, only HDMI 1.3 has built-in future capability of resolutions as high as 2560 x 1600p (“1080p” video is 1920 x 1080 pixels) should those ever become available on disc or from broadcast sources.

10. Q. I have some DVD-Audio and SACD high-resolution audio discs. Will HDMI cables stream those multi-channel digital signals to an AV receiver?

A. Beginning with HDMI version 1.1, support was added for DVD-Audio;  HDMI 1.2 and all subsequent versions of HDMI added support for SACD (one-bit audio). Some Universal DVD players that play DVD-Audio and SACD, for example the Oppo HD970, may convert SACD to linear PCM and output that over HDMI, in which case an AV receiver that will handle multi-channel linear PCM will play those discs with no losses of audio resolution. DVD-Audio is always converted to linear PCM for streaming through HDMI versions 1.1 and later.

11. Q. With all these digital audio and video capabilities, are HDMI cable lengths really critical?

A. Yes. Actually, the thickness of the internal wires—the cable gauge—matters just like with analog speaker cables. For example, if the HDMI cable’s internal wires are 28 gauge, then you can run up to 16 feet or 5 metres. More robust cables with thicker 24-gauge wires will operate up to 39 or 49 feet (12 to 15 metres). Note that the given figures are for ideal conditions. Many cables will not transmit over these lengths. For very long cable runs, there are alternatives like CAT-5 cables that can extend HDMI to lengths of 300 feet or more.

So that’s the really important stuff about HDMI—for now. Yes, there were 11 questions, but HDMI has so many aspects to it that ten facts didn’t seem to quite cover it. I’ll leave comments on some of the other HDMI capabilities covering “Deep Color” and other features for the next article.

However, once your set reaches your living room, the "Dynamic" setting (a common name for the factory default) should be banished from use: it often produces a garish, neon-like unrealistic picture with no detail in bright or shadow areas and almost cartoonish color and skin tones. So before you do anything else, turn off the Dynamic or "Vivid" setting and select "Cinema" or its equivalent and "User Settings." One other suggestion, in passing:

Resist the urge to mount your LCD or plasma panel over the fireplace.

That kind of placement often puts the image uncomfortably high from a normal sitting height and most of us don't like looking up that far. Besides, ambient heat from the fireplace may shorten the life of the set. Excessive heat is the enemy of all electronics.

What follows are five adjustments you can make anytime, even while you're watching, that will greatly enhance the overall picture quality of your new TV no matter what the video source-- Standard Definition TV, DVD movies, and High Definition programming from cable, satellite, off-air or from HD discs (Blu-ray/HD-DVD).

Turn down the room lighting.

This may seem obvious, but lots of viewers ignore it and put up with a degraded video picture. TV control rooms and mixing suites are very dimly lit for a reason, because no matter what type the display (LCD, plasma, CRT, DLP, LCoS, or video projector), it's only in a dimly lit room that a TV image will show the full range of gradations from deep black through grays to white with all the nuances of color. The room doesn't have to be pitch dark; set the lighting to the same level as an intimate restaurant where you can still read the menu. I'm not a fan of putting a small light behind the TV, an approach advocated by some critics-the "halo" effect behind the screen takes away from the impact and "pop" of the image. Instead, put a light elsewhere in the room that doesn't cause reflections on the TV screen.

Before you try the following steps, connect your DVD player to your new display using the highest quality video input available, which for new HDTVs will be component video or HDMI/DVI, followed by S-Video and composite video for older standard TVs. Then call up the user menu for your new TV and click on "User Settings," which will let you adjust specific picture qualities and will remember your settings. On some sets, the factory default modes ("Standard", "Sports", "Vivid" etc.) lock in picture settings and won't let you make individual picture adjustments.

Three Simple Controls (you don't have to buy special calibration DVDs):

Brightness (black level)

This control is misnamed. It really should be called "Blackness" because this control actually sets how black or dark the darkest portions of the picture will appear on the screen. One good way to set this without going to special calibration DVDs is to load your DVD player with any wide-screen DVD you have that has "letterbox" black bars above and below the picture.

While you are watching the black bars above and below the image, turn up the black level (Brightness) control all the way until the black bars appear gray. That's too far, because now anything black in the original video image will look gray. Now gradually bring the setting down until the gray bars just begin to look black. That's the setting. When you look at the picture, anything that's black should appear black, but look at shadow areas to see if you can make out some detail. You should be able to see a little detail in the shadows; if you can't, then increase the Brightness just a bit-but only a bit-- because you don't want true blacks to turn gray.

Contrast (Picture)

The "Contrast" control is also a misnomer; it should be labeled "White Level" because it regulates how white the brightest parts of the picture will appear. To adjust this, find a scene on a DVD or a live broadcast that has a wide range of light to dark; even an outdoor sports broadcast with sunlit areas will do nicely. Now pause the DVD image (or freeze the image on live TV) and turn up the Contrast (White Level) control all the way until the very brightest areas lose all detail. Look for someone wearing a white shirt or light-colored clothing. When the control is set too high, you won't be able to see the buttons on a shirt or the creases and texture of the cloth. Now reduce the setting until you can just begin to see the buttons or creases in the shirt or other details in white areas. That's the spot to leave this control.

Different manufacturers of TV displays use their own system of demarcation or numbers for the above settings, so a number on one set won't apply to another brand, but generally speaking, the Brightness and Contrast settings should be between about 30% and 50% of their maximum settings. On my Samsung DLP HDTV, I typically set the Brightness (Black Level) between about 32% and 44% of its range and the Contrast ("White Level") at about 48 to 50%.

If you want to watch your display in a brightly lit room or daytime, you can always opt out of the Cinema setting and use a punchier "Standard" or "Sports" setting to yield a brighter and contrastier picture, or simply stay with "Cinema" and increase the Brightness and Contrast settings a little to compensate for the brighter room.

Color Temperature

Before we get to the Color or "Saturation" control, look on your TV set's menu for a Color Temperature control. It adjusts the tendency of the set to provide "Cool," blue-biased colors or reddish/orange-biased "Warm" colors. It affects all the colors your set reproduces as well as the Color and Tint adjustments, so set the color temp to "Warm" or "Low." (As it comes from the factory, it may be set to "Cool.")

Color (saturation)

Saturation or Color adjusts how intense or vivid the colors appear. If it's set too high, colors will be cartoonishly intense and unreal. When the color is too low, the picture will appear bleached out and, well, colorless! Now pick a scene from a movie or studio talk show that has several different skin tones in the same scene. Turn up the color control until Caucasian faces look ruddy or sunburned. Now reduce the setting until the skin tones look natural with just a hint of pink; other skin colors should also look natural at that setting too. You have to strike a balance between natural-looking skin tones and other colored objects in the picture; and you may find you'll need to tweak that setting for different video sources or movies of different vintages.

Final Tip

If it makes it easier for you, before you set the Brightness and Contrast controls, turn the Color control to zero, which will make the entire picture black and white. You may then find it easier to adjust Brightness (Black Level) and Contrast (White Level) without the distractions of all those other colors. Once you have Brightness and Contrast properly adjusted, then turn up the color control to re-introduce colors into the picture.

You may be wondering about "Tint" and "Sharpness." Set Tint midway through its range and when the other settings are correctly adjusted, "Tint" should take care of itself. The "Sharpness" adjustment too is rather personal. Some viewers like a soft, film-like appearance; others prefer a kind of hyper-sharpness to the image. To start, put it at the midway position.

As to some of the special circuits included by different manufacturers to "hype" or exaggerate the video image, for the most part, sets will look most natural with those circuits turned off. Still, it's your set so if you like the look, go ahead and use them.

As you become used to the controls on your new display and how they affect the picture, you'll likely find you seldom have to adjust them except for minor tweaks to compensate for different broadcasts, DVDs and the peculiarities of some movie directors and cinematographers. Lately, there seems to be a trend among some movie directors for a kind of bleached-out, muted look a la "Minority Report" (for heaven's sake, don't use that DVD to make the aforementioned adjustments). Once all the basic controls are carefully set, "Minority Report" and other movies will appear the way the respective directors intended them to look.

What made the demonstration better than most was the presence in each room of identical loudspeakers and playback equipment with the music samples delayed and synchronized in a way that let you audition one music selection in the untreated room, then scamper across the hall just in time to hear the same musical selection played back in the treated room. Assuming you sat or stood in the same relative position in each room, the demo afforded an almost immediate controlled comparison of two listening environments. While I would have preferred to compare the effects of the room absorbers and treatments without the assistance of parametric EQ in the treated room, the demo nevertheless presented an unusual comparison that would be impossible to conduct in your own home.

High End Components

The stereo playback components were very tweaky and “high-end” – Talon Thunderhawk loudspeakers ($25,000) with a VAC Alpha vacuum-tube integrated amplifier ($10,000), a Wadia 581i disc player ($9,450), plus an assortment of exotic cables and isolation stands that added an additional $10,000 or so to the total.

The treated room used an RPG freestanding Variscreen ($700) absorber—a hinged upholstered panel with variable acoustic properties—a “broad bandwidth absorber” on one side and a “flat binary amplitude diffsorbor” on the other. The latter is adjustable with a “Variable Depth Air Cavity” that is said to control low-frequency modal problems.

In addition, a Modex plate ($1,000)—a damped metal plate system—was surface mounted in the treated room. Developed at Germany’s Institute for Building Physics at the Fraunhofer Institute (Europe’s largest applied research organization), the Modex plate claims to offer low-frequency absorption from 50 Hz to 500 Hz with a thickness of just 4 inches.

How Did They Sound?

Certainly the two rooms sounded different, and depending on the musical selections, you could come to a conclusion of which room you preferred. On the orchestral works, I slightly preferred the treated room. On a live jazz recording done in a club atmosphere, I liked the untreated room better, because the natural room reflections seemed to enhance the realism of the recording. Heard in the treated room, the jazz selection seemed more intimate, close up and dry—and somewhat less realistic to my ears.

Controversy

Still, the demonstration was worthwhile in the continuing discussion and controversy over room treatments—how much is too much? It also raises interesting questions about how we perceive room acoustics and how they relate to the realism of reproduced music. Should the acoustics of our living room or home theater be entirely negated and deadened in order that we hear only the ambience (or lack thereof) present in the original recording?

But what about entirely artificial studio-produced rock and pop recordings? For those, no real “room” or natural ambience exists, apart from the left-to-right stereo soundstage which is often artificially created with pan pots that electronically position a singer or instrument at a particular point across the stereo soundstage (at its worst, this is sometimes referred to as “multiple mono”). Sometimes digital reverberation, courtesy of Lexicon, is added to make the recording sound less dry. Vocalists are often acoustically isolated from the musicians in a small “booth” and close-miked to prevent “bleed” from other instrumental sounds and to remove the singer from any natural reverberance in the studio.

Should we listen to such recordings combined with the natural reflections or acoustics of our listening room, or hear the source exactly the way it was recorded, with no additional “acoustics”—good or bad—imposed on the playback?

The Question

It’s an interesting philosophical question about music reproduction. At a fundamental level, whether we listen in stereo or multi-channel surround sound, we are seeking to create an auditory illusion—either of musicians performing in our home or within a particular acoustical space. Should the recording transport us to the ambient space of the recording? In the case of concert-hall, jazz-club and rock-concert recordings, I think most of us would agree that’s the goal.

But what of performers intimately recorded in a dry studio setting? I believe we want the illusion of those performances and musicians transported to our own listening room. Should our home theaters or living rooms, therefore, be part of that process? I rather think they should—but of course that does mean that the recording will sound somewhat different in every room it’s played in.

Conversely, should we use every means at our disposal to absorb and eliminate any of the specific reflection modes our rooms generate in order to hear exactly what the recording engineer, artist and recording producer put on the master tape? If you follow through on that argument, then why not simply listen on headphones and eliminate your listening room’s liabilities entirely?

Obviously, headphone listening has its own peculiar artificiality, with vocalists centered in the middle of your head and the musicians spread from ear to ear. Granted, it has its own intimate appeal, and is wonderful for portable listening and travel, but it does not effectively recreate a 3-dimensional space of the kind we often experience with great multi-channel recordings and even some stereo playback.

It’s all very well to control and try and smooth out the worst bass standing waves from room modes, and this is a worthy goal. But I’m convinced that a room’s natural acoustics—by which I mean a room with a typical mix of absorbent and reflective surfaces—mostly contribute to the realism of reproduced music. And this realism may be further enhanced by the spatial qualities of the loudspeaker. The first and secondary reflections may add a natural airy and open quality to the music, particularly if the speakers have smooth off-axis lateral dispersion. (That means that musical sounds heard at angles away from the speaker will resemble the tonal balance of the same sounds heard directly in front of the speaker, and that the speaker will smoothly radiate sounds across the musical spectrum at various angles into the room.)

Singers and Instrumentalists

In real life, musical instruments and vocalists radiate sound in every direction, albeit with some bias to the direction that the singer or instrument’s bell or horn is facing. Does it not follow that if a speaker is reproducing those sounds, it should attempt to roughly simulate the dispersion patterns of the original musical sources? (It’s one of the reasons that the most realistic sounding surround speakers like Axiom’s QS8s use multiple drivers, so they can mimic the delayed reflections that occur in larger halls, theaters, and outdoor settings.) If you overtreat a room to soak up most of those delayed reflections, you kill off some of the realism and sense of envelopment in an acoustic space.

In addition, we each subconsciously “know” and are familiar with the naturally occurring reflections of our own listening room, because we live there. Admittedly, the time delays involved in most domestic rooms are much shorter compared to those encountered in larger clubs, halls and concert halls in which musicians perform. But our brains and hearing mechanism are still acutely sensitive to these delays and process them along with the ambient delays present on many recordings to lend a sense of realism to the illusion that’s taking place in the listening room.

This isn’t meant to be the definitive guide to listening rooms; rather, it’s a presentation of the complex arguments on both sides. My own bias is undoubtedly apparent, but I hope the foregoing stimulates your own thoughts about how we hear and appreciate recorded music in our homes. Share your experience of treated versus untreated rooms here.

New models of consumer electronics products almost change with the seasons: you've finally understood why you need a High Definition Television (HDTV) when along comes yet another electronic upgrade. As exciting as these developments are, they may also provoke vague feelings of discontent. This can occur if some know-it-all points out that your HD display is only 720p. When this happened to me recently, I countered with the fact that I was viewing HDTV while this person was still in nursery school. ( Japan developed an analog version of HDTV in the 1980s, which I saw on press trips to Japan and later viewed in Canada when TV broadcasters there considered adopting the Japanese HDTV system for the future needs of Canadian TV broadcasting. It was ultimately rejected.)

As many readers are aware, the 1080p tide has been rising for at least a year and this spring it seems to have reached a new high-water mark, in part stimulated by the market appearance of new high-definition DVD players: HD-DVD and Blu-ray, recorded and studio mastered in 1080p. These two formats are not compatible (except for LG's HD-DVD/Blu-ray combo player, and a new combo unit due from Samsung), however they will play your existing DVDs.

Resisting the marketing juggernaut is never easy (we really know how to consume in the 21st century) so in the spirit of both welcoming and explaining 1080p, here are some guidelines to help you navigate the claims and counter claims:

1. What is it? 1080p stands for 1080 progressive. It means that a video display or video source has the capability to display a high-definition video image made up of 1080 horizontal lines progressively scanned from the top to the bottom of the screen. Your old analog CRT set yielded about 330 lines. A standard DVD player delivers 480 lines. In techie terms, a 1080p high-definition set will display an image comprised of 1920 x 1080 pixels, or approximately 2 million pixels (a pixel is a picture element) versus a 720p image, which consists of 1280 x 720 pixels, or about 921,600 pixels. Other things being equal, the more pixels there are in an image, the greater the potential detail and clarity.

1080p is a refinement of HD video technology that has evolved from earlier HD displays known as 720p or 1080i (i for interlaced). The latter (720p or 1080i) are the existing standards for HD images broadcast over the air or by cable or satellite. Broadcast 1080p images are not available—yet. But they may be some years down the road.

2. If you own or buy a new 1080p set, it will convert or upscale incoming 720p or 1080i images to 1080p. The upscaled images may look smoother and more nuanced, clearer if you will, than those viewed on a 720p set.

3. If you already own an HD set that is several years old, it will likely be a 720p model (rarely 1080i unless it's a CRT HD set), so there is no point in getting video sources that deliver a 1080p image because your video device can't display the extra pixels, unless of course you decide to replace your 720p or 1080i HDTV with a 1080p HDTV.

4. If you are deliberating about buying a new 1080p large screen display, then it will let you do two things: either sit closer to the screen than you otherwise could if you had a 720p display, or, if you decide to go for a 1080p front projector, then you could project a considerably bigger screen image that would look as clear and sharp as a 720p image viewed from twice as far back.

For very large TV displays 65 inches diagonal, say, or projected images of 96 or 108 inches, you would see more detail from viewing distances of 5, 8, or 9 feet, respectively. Note that 9 feet is currently the average viewing distance for TV in most homes. On the other hand, because a 1080p set has almost twice as many pixels as a 720p display, subtleties and gradations of color and texture should be better, and visible.

5. Some new AV receivers and DVD players have built-in video up-conversion and scaling to 1080p. The upconversion to 1080p done in an AV receiver is only a convenience, and may not be executed as well as the conversion performed internally in your 1080p video display or projector.

6. Note that any 1080p display or 1080p projector will, on its own, upconvert any incoming standard or high-definition video source connected to it to 1080p. You do not need to purchase an outboard scaler in an AV receiver to perform that function. Your 1080p set will do that automatically because it must in order to display the image and fill all the pixels. (Techies call the latter the set's native resolution 1080p.)

7. You should also note that upconversion (scaling) to 1080p of standard definition (SD) video sources like regular DVDs or standard TV broadcasts will not make them look like a true HD image (720p or 1080i). They may appear smoother to the eye, but detail cannot be added by up-conversion.

8. The only sources currently available for true 1080p images are HD-DVD and Blu-ray discs, and those must be delivered from an HD-DVD or Blu-ray disc player via HDMI cables. HDMI connections carry video images as well as standard images and 1080p--in digital form, whereas component video cables are analog and carry 720p or 1080i HD images. While component video cables are technically able to pass 1080p images, Hollywood studios do not permit 1080p discs to be made without the anti-piracy digital handshake code that must be passed via HDMI cables. HD-DVD or Blu-ray players will only output 1080p signals over HDMI connections.

9. Finally, if you use a 50-inch to 60-inch diagonal HD display, and plan on sitting farther than 10 feet away from it, the 1080p display may not look any clearer than a 720p display would at that distance, however you may perceive a slightly smoother and more satisfying picture from the 1080p set. Still, we are talking subtleties here. Only if you sit 5 feet or so from a 60-inch 1080p screen will the increased clarity of 1080p be immediately apparent.

10. If you are about to purchase an HD set, then getting a 1080p display will future-proof your system because it will display the maximum picture resolution from HD-DVD or Blu-ray discs no matter which format wins, and it will be capable of displaying the highest clarity possible for almost any new video delivery system coming down the pipe. Of course, as we discussed earlier, there is always something else on the horizon, including the huge palette of colors obtainable with Deep Color, which new 1080p sets will be able to access through the latest version of HDMI 1.3 connections this fall.

Bargain hunters should note that 720p HDTVs and projectors are significantly less expensive than the new 1080p displays, often half the price of 720p sets 3 years ago. If serious budget constraints would make you compromise on other components in your home theater setup (e.g., a high-quality 5.1 or 7.1 channel speaker system) in order to get a 1080p display, then save some money and get a 720p set with an excellent home theater speaker system. A 720p HDTV display or projector is still High Definition and capable of beautifully detailed video images.

Full disclosure here: of course we want you to purchase Axiom’s new weatherproof Algonquin Outdoor speakers, but regardless of what speakers you decide to get, there are issues about outdoor speaker placement, type, mounting, weather, wiring, and controlling speaker volume that you should consider.

Shelter from the Storm

Axiom’s Algonquins are waterproof and UV-protected, but remember that any outdoor speaker is going to be subjected to extremes of temperature, cold, snow, rainstorms and wind. It’s prudent to consider a location under the eaves of your house, where the overhang will at least partly shield the speakers from direct assaults by harsh weather or roving birds.

The Axiom Algonquin Outdoor Speakers in Arctic White.

As to placement, while such issues as the stereo soundstage and imaging really don’t come into play to the same degree they do indoors, if you have a central patio area, it’s practical to put one speaker higher up to one side of the area and the other speaker on the other side--as far apart as you need in order to provide good coverage of the patio or pool. Don’t go overboard, though. If you separate two speakers by more than 20 feet, you and your guests will end up hearing whichever speaker is closest, with little output audible from the other. That may be OK for some setups, but if you use a swiveling, tilting bracket (hint: Axiom’s Full Metal Bracket) that lets you aim the two speakers toward the area you want to cover, you and your guests will enjoy a reasonable stereo effect as they lurch about the patio toward the refreshments.

Professional installers generally recommend using one pair of outdoor speakers to cover an outdoor area between 200 and 400 square feet, which means a patio or deck measuring about 20 x 20 feet should be the maximum area served by a speaker pair. It’s worthwhile using a couple of stepladders as temporary speaker supports while you judge the sound coverage to the patio, deck or pool area from different locations. Do this before you start drilling holes for the speaker brackets and wiring.

Beefing Up Bass

The fact is that almost all outdoor speakers use small sealed enclosures, but this severely limits bass output where you need it most--outside. Axiom's Algonquin M3 is a bass-reflex design with a specially designed port that uses a screen to keep critters out and is angled so the rain will not get inside the speaker whether it is mounted horizontally or vertically. The screen is up inside at the end of the port and is not removable.

Your outdoor speakers won’t have the usual boundaries common to indoor rooms—walls, ceiling and floors—which help reinforce the deep bass, so try and avoid mounting them on a post where there are no helpful boundaries to beef up the bass. Under the eaves, or, better yet, in a corner where the outdoor surfaces of the house meet, will supply some supportive bass reinforcement. An outdoor speaker mounted between two intersecting surfaces under the eaves will increase its audible deep bass output by two times or more.

Amplifier Requirements

Outdoor speakers have to work harder because they fire into infinite space, so if you plan on using the Zone 2 outputs from your AV receiver or integrated amplifier to drive them, make certain the amplifiers have sufficient power output. As a party tempo increases, playback volume tends to rise, so an amplifier with at least 80 to 100 watts per channel should be considered. Don’t use some ancient stereo receiver from the basement storage room with 20 or 30 watts per channel-- the power demands for outdoor playback will likely drive the amp into clipping and damage the speakers.

The Neighbors

Don’t forget nearby homes or your neighbors across the water when you’re deciding on the speaker locations. Aiming the speakers from higher up down toward the patio or pool area and away from neighboring yards or houses will help focus the sound in your immediate area.

Cables, Drilling and Brackets

For wiring runs longer than 40 feet, use 12-gauge speaker cable if you want to avoid losses from resistance. You can certainly use 14-gauge cable for distances of less than 40 feet with insignificant losses. For speaker locations away from the house at a pool or patio area, you should consider using 12-gauge direct-burial cable rather than running cable along the ground.

Here are some guidelines for drilling and mounting speaker brackets, including Axiom's Full Metal Brackets, to various surfaces. With brick homes, you will need to use a masonry drill (available at hardware stores for a few dollars) of sufficient diameter to accept a concrete anchor or plug somewhat like the drywall plugs used indoors for bracket mounting. After drilling the hole, tap the concrete anchor into the hole and use stainless-steel (non-rusting) screws shorter than the concrete anchors to affix the bracket. Use some silicone seal or Goop around the screws to prevent moisture from getting into the brick. Concrete block surfaces may require using a hammer drill that both rotates and pounds the bit to penetrate the material.

If you have aluminum or vinyl siding, you’ll need to drill through the siding (go through the narrower part at the top) to the material beneath—likely wood, plywood or studs—to anchor the wood screws. The vinyl or aluminum siding by itself isn’t strong enough to support the weight of a speaker and the bracket will sag. Seal around the screws and bracket with silicone or Goop to keep moisture out.

Be very careful with stucco walls not to crack the stucco. Use a masonry drill to go through the stucco to the material beneath, likely wood, and wood screws for that material. With some cement-board or composite siding materials, a wood drill bit and screws will usually work fine. Again, be sure and use rust-proof screws and silicone seal around the screws and bracket.

Wood or log siding is the easiest of all to anchor brackets to. Just use rust-proof wood screws of an appropriate size and length.

Drip Loop

Once you’ve determined where you are going to mount the speakers, you’ll still need to drill a hole through the wall for the speaker cable. You can locate that behind the speaker to conceal the wiring. Follow the aforementioned guidelines as to drill bits and wall materials. As to the speaker cabling, you can run that inside the walls to the exit holes you’ve just drilled through the wall surface. Leave enough extra cable outside the drill hole to form a drip loop—a U-shaped jog in the cable between the wall surface and the speaker terminals that will allow water to run down the cable and drip off the bottom of the loop, rather than flowing into the speaker terminals or running back into the hole for the speaker cable. Seal the hole in the wall with silicone or Goop.

You’ll likely want to add some means of remotely controlling the volume of your outdoor speakers as well as changing discs or programming either by using an infra-red repeater that leads to your main AV receiver, an RF remote, or with an externally mounted volume control. Weather-resistant external level controllers and keypads can be obtained from various suppliers. A convenient no-hassle alternative would be to purchase an RF (radio frequency) remote control whose signals go through the walls to your AV receiver. Be sure to try one out to check its usable range (with an option to return it if the range is too limited or iffy). Depending on the wall surfaces (concrete or brick, especially), the operating range of an RF remote may be quite limited.

Pictured above, Axiom's Epic Grand Master Speaker Package in an In-Wall/On-Wall Configuration.

Small: If your room is small, say, a den or a bedroom, of less than 1,500 cubic feet (a 10 x 12 x 8 foot room is 960 cubic feet), start by looking at the Epic Midi Home Theater Package. You'll also need an A/V receiver. The Denon AVR 1706 is a 7.1-channel model we like with this system. For even more features, consider the more powerful and versatile Sherwood Newcastle 771. If you don't already have a DVD player, look to the Panasonic DVD-F87 five-disc changer, or a universal upconverting DVD player by Oppo Digital. Your DVD player will also play CDs, so you can save room in your equipment rack by using one unit for both functions.

Medium: Moving into a typical-sized living room, in a standard home or an apartment, 1,500 to 2,500 cubic feet (about 19x13x8 feet is 2,000 cubic feet), consider the Epic Grand Master Home Theater. With this Axiom system, the Sherwood Newcastle R-871 7.1-Channel Receiver with HDMI inputs is a great pick. It's a dual-zone 7.1-channel A/V receiver that will grow with your needs. Like the Sherwood Newcastles, the Denons in this price range have robust amplifiers that will drive 4-ohm loads like the Axiom M80 v2 towers. For a step above the normal DVD player, look to Universal DVD players that play hi-res SACD and DVD-Audio discs as well as DVDs: we like the excellent Sherwood Newcastle SD-860 and the Oppo Digital 970HD or Pioneer DV-578A.

Large: Finally, for large rooms or 'great' rooms with cathedral ceilings, the Epic 80 Home Theater Package or Epic 60 Home Theater will provide excellent movie-theater-like surround sound. Larger rooms need more amplifier power, so consider separates: the Sherwood-Newcastle A-965 7-Channel Amplifier will provide real-life volume and will drive 4-ohm loads like the Axiom M80 v2 towers with ease. You'd need to pair the A-965 with the P-965 AV processor. In all-in-one AV receivers, the very powerful Sherwood R-965 is an excellent choice, as are the Denon AVR-2807 or other Denon higher-end models. With this system, consider adding a Universal DVD Player with video upconversion, such as the Sherwood Newcastle SD-871, a universal DVD-V/ DVD-A/ SACD player with HDMI.  The Denon DVD-2910 is also a good choice. These will enhance standard DVD picture quality to almost-high-definition quality, so that your video image will be as excellent as your sound. 

Axiom has a variety of other speakers and subwoofers that you can choose to tweak your system to match your movie and music preferences exactly. Call one of our friendly, non-commissioned Home Theater Experts at 1-888-352-9466, or send them an e-mail. We're always happy to help!

If you're interested in a home theater speaker system, contact us for a recommendation based on your needs.

If you have a floorplan or room layout, send it to us online from this page, or contact us for faxing instructions. One of our Audio/Video experts will work with you to recommend loudspeaker selection and placement, and help with other questions you may have about audio video equipment selection including receivers and amplifiers, room design, and acoustical considerations.

If your listening area is small, like a bedroom or den, consider compact stereo speakers. If you are putting the speakers in a large great room, you'll want to look at our floorstanding tower speakers and subwoofers for thrilling musical reproduction. Worried about space? Axiom has a hi-definition in-wall speaker line that delivers no compromise sound without taking up any floor or shelf space.

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Get your own personal audio/video advisor.

Call for personal advice Toll Free at 1-888-352-9466 between 9am and 11pm Eastern, Monday to Friday, or 10am and 9pm Eastern, Saturday and Sunday, or e-mail us anytime. We're happy to help! Alan Lofft (pictured left) former editor of Sound & Vision (Canada), senior editor of Audio (New York) and his team of experienced experts, will give you down-to-earth, honest, friendly help.

"Thank you for the prompt delivery of my M80s. I can't believe the other speakers of comparable quality are being sold for more than twice the price... Your speakers' overall quality are absolutely mind-blowing! :-) I am VERY HAPPY! You make world class speakers at an affordable price. Thank YOU!" - Jim Z, NC
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Why rear projection?

Any ambient light falling on your screen in a conventional home theater room is a major factor that will degrade a front-projected image. By installing the projector in an enclosed room behind the screen, which can be kept completely dark, you eliminate virtually all ambient light that could interfere with the light path reaching the screen. Rear-projection systems have an added advantage of keeping your valuable audio/video gear out of sight and secure.

Most in-wall rear-projection systems are designed into new construction projects or rooms undergoing remodeling, primarily because a rear-projection system requires a significant amount of space for the throw distance behind the screen. A specialty installer might also consider an optical mirror system to fold the projected light path and reduce the required throw distance by up to half.

Special screen material

Rear projection requires a special translucent screen material because the image is viewed from the opposite side of the screen. Such screens are available in a variety of sizes and aspect ratios from Da-Lite, Draper Cineflex, Stewart Filmscreen and other vendors, and start at around $359US. There are also special translucent acrylic versions with very high gain (up to 7.5). Position a compact DLP or LCD high-definition projector in the utility room behind the screen, so it throws its image to the screen in front. It's important that the entire utility room - floors, ceiling and walls - be painted a flat black to absorb stray light of any kind. On the other side of the screen, of course, is your home theater room. The screen itself, when not in use, could be covered by remotely operated curtains just like in a real movie theater.

Why do this? By centering the projector and placing it as close as possible to the screen (within the limits of the projector's lens), it provides a very bright image because of a shorter “throw.” In the theater room, the image can be viewed with ambient light present and still be highly acceptable—brighter and with better blacks than an image from a front projector in the same room as the seating, where any ambient light falling on the screen washes out the blacks and contrast. It's really a variation of a self-contained LCD or DLP rear-projector, but it eliminates the bulk of the latter by moving the projector to the utility room behind the screen.

Of course this setup will require a DLP or LCD projector with remote-controlled focus and zoom lens, as well as remote infrared sensors in the theater room, so you can control not only the projector but the AV receiver and DVD player or other associated AV gear. Variations of this are possible, depending on whether or not you want immediate access to your AV preamp or receiver in the theater room, or whether an infra-red sensor or module in the wall will be sufficient. The projector will also require an image reversal switch, because otherwise the projected image would be backwards when viewed from the other side of the screen.

Axiom's exhibit at the Toronto Interior Design Show 2007 (IDS07) earned a Silver Award for Best Booth Design in the 400+ square foot category. The exhibit, demonstrating new ideas for integrating audio/video systems with world-class interior design, featured a three-room mini-home constructed on site and showcasing the design talents of Gluckstein Design, one of Canada 's leading interior design firms.

IDS07, held February 22-25, 2007 at the Direct Energy Centre Exhibition Place in Toronto, is Canada 's premier platform for contemporary residential design. The show's design awards, sponsored by Audi, the German automaker, reward exceptional creativity, quality and overall good design.

Axiom Audio's IDS07 house included an entry/study, an entertainment/media lounge, an eat-in kitchen, and an “outdoor” terrace, all fully decorated. Each area of the Axiom Audio home included the latest Axiom prototype loudspeaker and amplifier products, placed specifically to demonstrate the company's unique strength in blending exceptional audio with top-quality interior design. Among the several products showcased were Axiom's T100 and T22 in-wall speakers; EP400 Intelligent DSP subwoofer; M2 VaSSallo Series bookshelf speakers; MZero and EPZero Computer Sub-Satellite System; and “green” outdoor wireless speakers containing a 15-hour battery that can be recharged by solar power.

“Axiom Audio is especially pleased to receive this award because it validates one of our primary reasons for exhibiting at IDS—namely, that great audio and top quality interior design can co-exist,” said Ian Colquhoun, president and chief designer of Axiom Audio. “For some time, Axiom's product approach has been to emphasize beautiful cabinetry and innovative mounts and speakers that allow loudspeakers to 'recede' into a room's design, creating harmony between décor, audio and video.”

To see more pictures from the show, log on to our message boards and visit the 'What's New' section.

Judging by the number of threads on the Axiom message boards about setting subwoofer loudness levels relative to the other speakers in your stereo or home theater surround system, there seems to be uncertainty about how to do it and what constitutes the “proper” or correct level, if there is such a thing. (I tend to think not, as personal preference for the amount of deep bass output varies considerably from one person to the next.) However, it’s still important to get the acoustic output levels of your subwoofer and the  other satellite speakers roughly the same, then, using that as a base, do the fine-tuning based on the material you’re watching or listening to.

Since it had been some time since I tweaked my own subwoofer levels, I decided to explore the differences in settings using different test signals and sources. I used the Avia Guide to Home Theater DVD, Digital Video Essentials DVD, the Sound&Vision Home Theater Tune-Up DVD (a simplified version of the Ovation software used on the Avia disc), Chesky Records’ Ultimate DVD Surround Sampler & 5.1 Set-Up Disc, and the Dolby Digital test tones available from my H/K AV receiver.

Axiom's new EP400 DSP Subwoofer, the smallest DSP subwoofer in our lineup.

All these sources use different combinations of either warble tones or pink noise, sometimes full-band or band-limited, which sequentially rotate through each of the speakers in your system and the subwoofer. A RadioShack Sound Level Meter set to the “C” weighting scale and the “Slow” function, is essential. As you hold the meter in front of you at head level pointed upwards, you can then individually adjust the output of the subwoofer and balance it to each speaker in your 5.1-channel surround system. Or at least that’s the theory.

Where to start? Go into your receiver’s setup menu and adjust all the individual levels for each speaker and the LFE subwoofer output to 0 dB. (I’ll assume you’ve already set the AV receiver’s internal bass management correctly. In most systems, at least at the beginning, set everything to Small and the subwoofer crossover frequency in the receiver to 80 Hz. Later on you can experiment with different settings if you want.)

On the rear panel of the subwoofer, set the volume control to the mid-point or a bit less, and turn the subwoofer’s own crossover control to Bypass (if it has a bypass setting) or to its maximum rotation. Note: If a user wants to experiment and set the subwoofer's crossover at the same frequency as the receiver's crossover, better integration of the subwoofer may be achieved. Experiments at  Axiom have shown that with the EP400/500/600 subs, it's advantageous to do so because of the brick-wall algorithms in the DSP circuits.

Now pick a volume setting on your AV receiver that’s typical of the range you usually listen at. Most people find that 70 or 75 dB on your SPL meter at your listening seat is a comfortable playback level. While 85 dB SPL is often used for THX movie theaters, that level is simply too loud for most listeners with test signals in the confines of an average-sized home theater or living room.

I think much of the disagreement over setting subwoofer levels is based on a misunderstanding of how we hear bass frequencies. Our ears are quite insensitive to low bass compared to midrange frequencies, so depending on the level you initially set your AV receiver at and use to run the test tones, you may find that you are setting the subwoofer levels either too high or too low. I used 70 dB SPL at my listening seat and I found that I was setting the sub levels to +2 dB above 0 dB. If I lowered the sub level to 0 dB, there wasn’t enough deep bass when I played music or soundtracks. But if I used 80 dB SPL to set the subwoofer/speaker balances, I got more accurate settings, because when I listen to music, the levels often average about 75 dB to 80 dB SPL, peaking at 85 dB SPL at my listening area (subjectively most people call 85 dB “Loud”).

What surprised me were the variations and inconsistencies in subwoofer levels depending on which test DVD I used. The most accurate—for my particular room and listening tastes—turned out to be the Avia Guide to Home Theater. In particular, the bands of high-frequency and low-frequency noise (found in the “Advanced” chapter, under “Subwoofer Setup”), which alternated between each satellite speaker and the subwoofer, respectively, allowed me to set very precise and pleasing balances. The other test DVDs, while useful, just didn’t seem to be as accurate for my room and setup. Chesky Records’ Ultimate DVD Surround Sampler & 5.1 Set-Up Disc had lots of interesting subwoofer test signals, and because it had DVD-Audio tracks, it was useful for calibrating speaker levels for DVD-Audio disc playback.

It’s important to note that the recommendations and settings you get using any of these test DVDs are not carved in stone, and you’re going to want adjust the subwoofer levels to match the source material, which you can do by ear. Some CDs have almost inaudible bass—I’ve had to increase my sub levels by 5 or 6 dB at times—whereas other CDs or DVDs may have overwhelming bass that you’ll want to reduce. After a time, you’ll get to know your system and the balances you prefer. Don’t hesitate to alter the sub levels to suit the recording or movie-- and your own taste. It’s your system, after all, and you can set the levels anywhere you darn well please (with some consideration for others and neighbors, of course. . .)

To avoid the latter scenario occurring when guests visit your place or simply to get the maximum performance out of your brand new HDTV set or an older CRT (picture-tube) set, here is a list of typical TV picture ills, and a basic guide to fixing them. Many of these might result simply from an inadvertent press of the wrong button on the remote, either by you or another user.

The “Big, Heavyset” Look

The Problem. Everyone on screen looks like they've been hitting the donut counter or hoovering up too much good food. In almost all cases, someone has inadvertently activated the “stretch” mode on a new widescreen TV. This tells the set to digitally expand a standard, squarish non-HD 4:3 image to fill the widescreen aspect ratio so that no black borders appear at the sides of the screen. It's nice not to see black borders, but “stretch” modes will also tend to expand the horizontal girth of anyone on-screen. Sometimes the actors in the center may be left untouched, but as they exit left or right, they stretch to larger proportions.

The Fix: To cancel this mode, look for a picture size control on your TV's remote and go through the options until figures on-screen look normal. Set it to “4:3” for non-high-definition TV images. The widescreen aspect ratio is part of the HDTV standard, so if you are watching HDTV programming, then set the TV for “16:9” or “widescreen.” With the right setting, your HDTV should display conventional non-HD 4:3 images with black borders to each side (get used to them!) and automatically go to undistorted widescreen images with an HDTV program.

Peculiar Skin Tones

The Problem: Skin tones seem too ruddy or reddish. Actors look like they should book an appointment with a dermatologist or sign up with the local chapter of AA (this does not apply to persons or actors with a naturally ruddy complexion).

The Fix: On an older CRT picture-tube set, start by going to the Color control and reducing color saturation (lessens the intensity of all colors). Now look at the skin tones. Are they still too red, or just a few whom you suspect might have a naturally ruddy complexion? In most cases, the Tint control should help you achieve correct skin-tone balance. Older sets may have an auto-color or auto-skin-tone setting that may give everyone a kind of peachy pallor—pleasant but not realistic. Turn that control off and individually adjust the Tint control for natural skin tone, depending on the program (programs shot on film may look different than programs shot on video, and you may have to compensate). Either that, or put up with peachy looking skin tones that auto-color circuits tend to deliver. Newer HDTV sets may have elaborate color and tint adjustments that let you vary skin tone with quite subtle settings until you're pleased with the result. Your set may also have “color temperature” settings, often with labels like “Warm”, “Neutral” or “Cool”. These will affect the overall appearance of colors and skin tone. Start off with the “Neutral” midway setting or “Warm” and see which looks the most realistic.

HDTV and Standard TV Look the Same

The Problem: High Definition TV (HDTV) broadcasts, which are supposed to look much sharper and clearer than standard DVD images, look the same, even though you bought an HD set. Or perhaps you see no difference between conventional standard TV broadcasts and programs broadcast in High Definition.

The Fix: If you get your TV from cable-TV or satellite, first confirm that you have an upgraded cable or satellite set-top box that is capable of HDTV reception. HD channels have different channel numbers than standard TV channels for the same programming and your set must be fed an HD signal in order to display it. Likewise, owners of “cable-card” HD sets must ensure that the cable card is upgraded to receive HD broadcasts from the local cable-TV system.

One of the most common problems is incorrect connection of the cable or satellite box and your HDTV, and this sometimes occurs even with cable-guy installers. To deliver HD programming to your new HD video display or projector, the cable/satellite set-top box must use either component-video connections (three separate RCA cables color coded red, green and blue) or an HDMI/DVI output, which looks like a computer multi-pin connector. If you are using a single yellow (composite) video cable or S-video cable like the ones we used from VCRs, you won't see HD resolution and clarity.

Be sure and go into the digital cable box or satellite receiver box menu and set the output of the cable box to match the “native resolution” of your video display. Most, plasma, LCD, DLP, and LCoS displays and projectors are “fixed-pixel” arrays, and you should set the cable box to “720p,” which is one of the two HD standards. Although broadcasters, satellite services, and digital-cable services use both 1080i and 720p to distribute programming, don't set the cable box or satellite box to 1080i, unless your video display is a picture-tube (CRT) HD set. (N.B. There is one exception: Some of the new 1080p displays will accept and de-interlace a 1080i input, so you'll benefit from the full resolution of a 1920 x 1080p display. If your set is one of these models, then set the cable or satellite box to output 1080i.)

Generally, check your DVD player and set it to output “480p” and use the component video cables (3 cables, red, green and blue) for connection to the video display or to your AV receiver and then to your TV. If you happen to have a new “upscaling” or “upconverting” DVD player that uses an HDMI or DVI digital video connector, set the player to your set's native resolution, which in the case of most HD plasma, LCD and DLP displays will be “720p.” Note that Standard DVD (480i or 480p) is not High Definition, and do not expect your upscaling DVD player to produce HD picture quality from a standard DVD. Nevertheless, upconverting DVD players may yield a slight improvement in picture smoothness with the upconversion feature in use. Only the new HD-DVD and Blu-ray formats deliver High Definition from special HD- DVDs or Blu-ray discs.

Video Projectors

The Problem : The projected picture looks good but appears somewhat blurry or “soft.”

The Fix: Most video projectors have a manual lens focus, so first check the focus carefully. Any adjustment of the zoom lens may knock focus out of adjustment. Use a detailed scene or the text of the credits at the end of a movie or program.

Next, check the inputs on the video projector. For HD, you must use either component video (see above) or HDMI/DVI. And confirm that the cable/satellite box is set to the native resolution of the video projector—in most cases, 720p.

All HD and non-HD sets have an electronic “Sharpness” control that increases edge definition. If you like the hyper-sharp look, then turn up the sharpness control to your own preference--not too far, or you'll get noisy white halos around the edges of objects. Still, many viewers like some added sharpness. Some aficionados believe there is only one acceptable “look” to images. Not so. Nor does everyone agree on what constitutes a great-looking picture. For example, I often use the sharpness enhancer on my DLP set for live HDTV sports broadcasts simply because they look more “real” (closer to what I see in real life) and benefit from the added clarity. Film and video are quite different media, and they do not have the same appearance.

Others may opt for the smoother, softer “filmy” look.

While you're at it, check to see if your HD set has a special automatic sharpness and contrast-enhancing circuit (for example, Samsung's “DNIe” circuit—Digital Natural Image Engine) to see whether you like its effects or prefer the smoother “film” look. Most of these circuits have similarly fancy proprietary names and can be defeated if the picture seems overly edgy or unrealistic. Look for a secondary button on the dedicated remote control supplied with the HD set and labeled with the circuit's fancy name or in the Picture menu.

Brilliant bright picture but detail lost

The Problem: the picture has great contrast and good blacks, but detail in white areas is bleached out.

The Fix: Go into the picture controls and lower the brightness (some sets call this “black level”), then adjust the contrast—usually by increasing it a bit--until you can just begin to see details in the white areas while still retaining acceptable blacks and contrast.

A very bright and contrasty picture initially impresses many viewers, so they run the contrast and/or brightness too high (it's called “torching” the set). Out of the box, your new video display may be set by the manufacturer to default to its brightest mode. Video cameras and displays don't have the same dynamic range as our eyes to extremes of dark and bright, so if the set is already set bright and a beach scene comes on, the little pixels oversaturate and lose all detail. See if your set has a “Cinema” mode, which will automatically lower the brightness and contrast settings. Use that and you'll see much more detail and gradation in tones and shadows, but you will have to reduce any ambient light in the room to appreciate the better picture quality. With contrast set too high, blacks will be black but all shadow areas will also be black, with no visible detail. Find a good compromise between good blacks, some shadow detail, and bright areas that still have some detail.

A related problem of messed-up picture settings may occur after a power outage or if someone has unplugged the set. This may cause the display to default to the factory settings for brightness, contrast, color and tint, and the picture will be disappointing. Not all sets have a memory to retain your custom picture settings if the set loses power. If all the whites look bleached out or too bright, or color and skin tones are out of whack, check the display's menu to see if it has reverted to the “factory presets.”

Front projection images seem washed out

The Problem: the image doesn't seem to “pop” or have enough contrast. Blacks all appear gray.

The Fix: There are two factors that cause this—either you have ambient light in the room, or your screen material (it may even be the wall) doesn't have enough “gain” or reflectance. Projectors have to throw light 10 to 20 feet across a room onto a big screen, so that light is precious. Video projectors will deliver their best images in a totally darkened room. Use blackout curtains or kill the ambient light in the room. You know how annoying it is in a movie theater if someone holds open a door at the rear of the theater and outside light floods onto the screen? The image immediately washes out. The same thing will happen in your home theater room if you have uncovered windows or any lights on.

Another factor to consider is your screen material. The more light a screen reflects back to the viewer's eyes, the higher its “gain” or reflectance. “Unity gain” is designated as one (1.0). Other things being equal, a high-gain screen with a rating of say, 2.0, will reflect more light along a narrower path than a screen with lower gain. Screen gains that measure less than 1.0 (negative gain) use a gray screen to absorb ambient light to help maintain contrast ratios. Some specialized screens are available with gain as high as 6.0, but there are usually trade-offs in terms of black levels (do blacks look really black or just grayish?) and viewing angles. Usually, the higher the gain of the screen, the narrower the viewing angle will be, i.e. the brightness of the screen falls off as you view the screen from increasing angles. This may be OK if all of the viewers are in the back part of the viewing cone and not sitting off to one side or the other.

Specialty Materials

One reader sent along a link to www.quietsolution.com which markets a popular specialty soundproofing drywall called QuietRock, comprised of three layers of viscoelastic, ceramic and gypsum material. QuietRock's QR-525, which incorporates these layers, claims to be remarkably effective—one 5/8-inch layer of it is said to be the equivalent of up to eight layers of standard drywall and achieve STC ratings of “up to 72”. It's certainly worth exploring these and other options.

That said, there is still no substitute for the tried and true construction techniques outlined in Part One—staggered-stud walls with double layers of drywall on each side, interior wall cavities loosely filled with sound-deadening insulation, solid-core doors (or double doors), weather-stripping, using dissimilar materials and/or air spaces and so on.

The Room Within a Room

But there is one soundproofing solution that tops them all—building a room within a room, which is derived from methods used to isolate recording studios and concert halls from all extraneous sounds and rumbles. Both the Glenn Gould studio in the Canadian Broadcasting Corporation's Toronto broadcast facility and Zankel Hall, the recital hall that is part of the Carnegie Hall complex in New York, isolated the recital halls from streetcar and subway rumbles, respectively, by constructing an interior hall that rests on huge rubber dampers. This room within a room technique not only excludes all exterior sounds but also prevents sound from within the halls themselves from escaping to other performance spaces in the buildings.

The Double Floor

You can use a similar technique by building a double floor (see illustration below) that rests on half-inch-thick rubber mats (look for these from specialty suppliers). The double floor with ¾-inch plywood on top and bottom, and fiberglass insulation between the 2 x 4 studs, supports the inner room, which also uses studded walls with drywall on both sides and sound-deadening fiberglass insulation within the wall cavities. A 6-inch air gap between the walls of the inner room and the outer room is sufficient to greatly reduce sound transmission. Carefully compute the dimensions of the inner room, taking into account the airspace between the inner and outer walls, as well as the actual thickness of the inner and outer walls, to come up with a consistent air gap of 6 inches. The dimensions of the inner room will, consequently, be much smaller than that of the outer room. The studded walls of the outer room should also use drywall on both sides.

Specialty sound-deadening insulation products are available for use within the walls and include such brands as Owens Corning QuietZone and Roxul Safe ‘n' Sound.

Since you've constructed an inner room and an outer room, it will by nature have two doors, which will be very effective in keeping sound from escaping. You should consult a specialty sound contractor for details on sound-deadening ventilation techniques that can be applied to the hot and cold air supply and return ducts as well as methods of wiring that prevent sound leaks to the outside.

It is beyond the scope of this article to go into precise carpentry techniques of floor, wall, joist, stud and header construction, but abundant material is available on the Web and in books. Here are some links to other sites and products that may prove helpful in your soundproofing endeavors:

http://www.quietsolution.com

http://www.roxul.com/sw47802.asp

http://www.owenscorning.com/quietzone/products/products.asp

An added benefit of soundproofing your home theater room will be that the soundproofed room will also keep annoying noise and outside sounds from entering the room. You'll have created a peaceful and quiet sanctuary in your home that shuts out the noise and clamor of daily life, be it car horns, coffee grinders, leaf blowers, or loud music on inferior playback systems (even those with wheels attached). Quiet spaces bring a measure of tranquility to our lives.

That said, soundproofing is a rather complex subject best treated in several articles.

Different approaches are required for new home construction or for soundproofing a room in an existing home. Soundproofing after the fact may involve building a room within a room, literally, depending on just how much sound you want to keep in and keep out of the room.

How Sound Travels

Let's look at sound, and think about how it travels in order to better understand how to stop it or contain it. Sound is made up of energized pressure waves in the air that cause objects in its path (including our eardrums) to vibrate—objects like walls, floors, doors and ceilings. When the sheetrock or plaster wall vibrates, those vibrations travel through the wooden supporting studs and joists (and to the drywall on the other side) conducting the energy to the next room and through the connected framing of the house. Deep bass energy is the worst, as you may have noticed when you walk past a dance club or when a car with a booming one-note subwoofer passes by your home.

Stopping sound in its tracks

There are three essential things that will stop or reduce the intensity of sound waves: air, mass, and distance. For example, a 6-inch-thick concrete wall has lots of mass, so it will stop a lot of sound because the sound waves lose energy trying to move the mass of concrete.

Anything that's heavy will help stop sound waves, and that includes adding a double layer of drywall, with alternating seams and with one layer placed vertically and the other layer(s) horizontally. Conversely, lightweight materials are largely useless in preventing sound transmission, with the exception of fiberglass batts used to loosely fill the cavities between walls.

Soundproofing and sound absorption

Don't confuse soundproofing with sound absorption. Sound absorption uses carpet, heavy draperies, closed-cell foam or similar material within a room to curb or absorb reflections, essentially to stop excessive echoes and reverberation. However these materials will do little to prevent the transmission of lower-frequency bass and vibration through the walls and studs and midrange sounds through air leaks to other rooms.

Obviously, sound loses intensity with distance, because the air offers resistance. If your house is a mile away from your neighbor's, it's unlikely the sounds from a subwoofer will ever travel that far. But within the confines of a house, any passageway that allows air to escape will allow sound to travel out of the room. Doors and windows are especially vulnerable, but don't ignore electrical boxes (AC outlets), wall plates, and heating ducts. The electrical boxes and wall plates can be sealed with a non-hardening silicone caulk. Interior sound absorbing baffles for heating ducts are available from specialty soundproofing supply companies.

Dual steel doors insulate Axiom's soundproof testing room where loudspeaker drivers are tested at power levels up to 1200 watts, which produce loudness levels as high as 135 dB SPL.

Replace hollow-core doors

Domestic hollow-core doors, for example, are largely hopeless at reducing the passage of sound. Replacing those with solid wood doors will help considerably. A steel door (again mass is important) will be superior and best of all are two doors, with effective weather-stripping seals on each side. (Remember that one door has to open inwards and the other outwards.)

Like hollow-core doors, single-pane windows have very little sound insulating properties. Double pane windows with an air space between the panes improve things considerably.

Dampening Vibration

The big word here is using non-hardening silicone caulk combined with different materials. Adding a second layer of sheetrock to a wall and studs coated with silicone where they meet will lessen the transmission of vibration. Adding a 6-inch air space between one side of the wall and the other will further reduce the transmission of sound. Filling the air space loosely with fiberglass will further increase transmission loss.

Dual layers of drywall (sheetrock, gypsum board) with silicone caulk between them are very effective, and adding a bead of caulk to the studs before the sheetrock is screwed or nailed will dampen vibrations. You can even get lead-lined sheetrock. Here, not only is the mass effective—it's very heavy—but the differing materials also help. Using different layers and kinds of material will reduce sound transmission significantly.

Overhead view of dual layers of sheetrock: place silicone caulk between
the layers as well as where the sheetrock attaches to the studs.

The Staggered-Stud Wall

This type of wall is a clever way of preventing the vibration on one side of a wall from

reaching the other side. A 2 x 6-inch base plate is used with alternating 2 x 4 studs arranged so that the 2 x 4s on one side do not connect with the wallboard on the other side of the wall. In other words, there are duplicate rows of 2 x 4s, in a staggered arrangement (see illustration, right) with the inside wall attached to one set of studs and the outer wall attached to the other set of alternating 2 x 4s. It's a clever way to achieve a high STC (sound transmission class) rating.

As can be seen, alternative construction techniques with dual layers of sheetrock combined with double-row or staggered stud construction and fiberglass can raise the soundproofing considerably past that of a concrete block wall.

These soundproofing techniques can be applied to construction of a dedicated basement home theater room in an existing house or to new home construction. The next article will deal with soundproofing an existing room in a house by building a room within a room.

Those variations serve as a textbook example of how grounding standards have changed over the decades and why, if you have a stereo or home theater setup that typically involves interconnection of various components, you may have experienced the persistent irritations of a “ground loop,” which produces annoying low-frequency hums and buzzes from your speakers and/or subwoofer and may even introduce curious patterns of interference into television pictures.

Some Basics

When we say “ground” we also mean “earth,” but from an electrical point of view, unless we step outside, the closest we get to a real earth ground is one of the prongs on an AC plug in the wall. In an older house or apartment that doesn’t have PVC (plastic) plumbing, the cold-water tap may lead to copper or lead pipe that eventually reaches true earth. When you stick a metal pipe into the ground in the context of an electrical circuit, the ground should have zero electric potential. If you put a voltmeter on it, you may get a fraction of a volt but it should be close to zero. But if you connected the voltmeter to the ground pin of an AC outlet in your home and to earth, depending on the competence of the electrician who wired your home, you might get a significant voltage differential in the reading, perhaps even a volt or two. It’s that voltage difference that will introduce ground loops and hum when you string together a number of components that may use different grounding systems. Adding to that are the different electrical potentials of the grounding shield from cable-TV distribution and satellite-TV installations.

Floating Ground

Electrical circuits, however, don’t necessarily have to be connected to a true earth ground; they may operate with a kind of “floating” ground. In fact, for the designer and engineer, the sense of “ground” may just become an intellectual convenience. For example, a flashlight and other battery-operated devices—even your car—work perfectly well without being connected to a true earth ground. In a car, the negative battery post and the chassis frame serve as the “ground” to complete the electrical circuits in the car, yet the entire car is insulated from the real earth by the rubber tires. In fact, the car is a good example of a self-contained electrical system tied to a common ground—the car chassis and the negative battery terminal. All the electrical devices on the car are tied to that common ground path through the metal car frame and body.

So within one system—say an AV receiver—the ground path may be tied to the chassis and one of the prongs on the AC plug or the third prong an a 3-prong plug, or it may not, in which case it could use an internal “floating” ground that’s not connected to the chassis.

History of Plugs ’n’ Prongs

A little history helps explain grounding incompatibilities. Back in the 1950s and early 1960s when hi-fi was invented in the USA, North America had not yet switched to a 3-prong grounding system or even a polarized 2-prong plug. In the 1970s and ‘80s, as Japan became a powerhouse in hi-fi, manufacturing and design moved away from the US, and because Japan was still on a 2-prong unpolarized AC plug and remained that way for decades, most manufacturers used an isolated ground system that wasn’t tied to the AC plug. That way a designer could also get improved signal-to-noise performance.

Three Prongs

When North America converted to a 3-prong grounding system, this was viewed as a good thing, provided the electrician wired your house and AC sockets properly. The 3-prong plug offered the possibility of a common ground path between all interconnected components, so long as all the components used the 3-prong plug. But as we know, that wasn’t the case: prior to the introduction of the 3-prong and polarized 2-prong AC plugs, manufacturers isolated the ground system within the component. Even the power supply for the audio circuits “floated”. In more modern components such as Axiom’s A1400-8 multi-channel amplifier, a “STAR” ground is used, whereby all grounds within the amplifier come back to a central ground that is tied to the center prong of the 3-prong plug. That’s all well and good, except within many AV receivers, the front main channel grounds are isolated from the surround-channel grounds. If an AV receiver’s pre-outs are connected with unbalanced RCA connectors to a 3-prong power amplifier, hum will likely result because of the lack of a common grounding path. Using balanced XLR connectors would eliminate all these problems, but only a few more expensive AV preamp-processors are equipped with balanced XLR connectors and, according to Tom Cumberland, Axiom’s chief R&D engineer, AV receiver manufacturers are unlikely to switch.

The good news is that Axiom’s Tom, along with other prominent and experienced engineers within the Consumer Electronics industry, now sits on Consumer Electronics Association panels to try and bring some standardization to the industry.

I’ve left out references to input and output impedances from this discussion, another source of wide variability in design standards that leads to problems in component compatibility. It’s a dense subject best left to a separate future discussion.

Hope you enjoyed this explanation of grounding! Check out the Tech Talk section of our newsletter archives for even more great information on common audio video questions.

Know your HDTV resolution numbers (do the math).

The latest marketing hype tends to exaggerate the clarity of "1080p" HD sets, if only to keep consumers hungry for the latest and keep the factories humming with new models. True, 1080p is the highest possible screen resolution and clarity available, but virtually all existing HDTV material, including network HD broadcasts and those from satellite and cable-TV systems as well as terrestrial TV stations is in either "720p" or "1080i, which are the two High Definition TV standards. Prices are falling but 1080p sets still cost about $1,000 more than a good 720p HDTV. Both 720p and 1080i sets are capable of visually stunning HD images.

Avoid "480p" sets. These are not HD and are sometimes called "Enhanced Definition" (EDTV) but they are only capable of displaying standard DVD resolution, not HDTV detail and clarity.

Here are the resolution numbers to look for in any true HDTV display or projector. Just multiply the two figures together to find the total number of picture elements (pixels) a display is capable of:

A 1080p set will state its resolution as 1920 x 1080p (that's about 2 million pixels, the highest available, and the most expensive).

A 720p set's stated resolution will typically be 1280 x 720p (about 921,000 pixels).

Resolution figures may vary somewhat from the aforementioned figures with plasmas, LCD flat-panels and also front projectors, e.g. 1366 x 768, or 1024 x 768, but so long as they are close to the HD standard, then you have an HD-capable display.

By contrast, a set that has 852 x 480p or 800 x 600p is not HD.

It will still look good with DVDs, but it won't deliver true High Definition images. Note that you'd still be able to view HD programs, but with reduced clarity and less detail. Do the math: 852 x 480p equals 408,960 pixels, less than half the number that a 1280 x 720p display will yield. The more pixels there are, the greater the potential detail and clarity from a video display.

For those who are considering purchasing one of the two new HD video disc formats HD-DVD or Blu-ray --and who want to future-proof their HDTV purchase, then it makes sense to consider a 1080p set because movies in the new HD disc formats are mastered in 1080p, and some of the players will output those signals to 1080p-compatible HD displays over HDMI outputs. However, at this juncture it's anyone's guess as to which HD disc format will find favor with consumers.

And don't obsess if you don't get a 1080p-capable set. Your 720p or 1080i HDTV will still deliver a beautiful High Definition TV image.

If you don't require an HDTV with a built-in tuner to receive local over-the-air HD broadcasts with an outdoor antenna, you may save money by searching for an "HDTV-ready" set that eliminates the internal HD tuner. These sets are scarce, because the Federal Communications Commission (FCC), which regulates the transition from analog to digital TV and HDTV, now requires that all new HDTV sets contain a built-in HD tuner. But the older models lacking one are typically less expensive than sets with built-in HD tuners or cable-card HD sets. Satellite dish systems and cable-TV providers normally supply (for a monthly fee or one-time purchase) the outboard HD tuner set-top box/DVR (Digital Video Recorder) required by their systems. These boxes/DVRs will tune in all the High Definition and Standard Definition channels available on the system, depending on which package of programming you buy. Newer HD cable or satellite boxes often contain two HD tuners plus a DVR, allowing you to record two different HD channels simultaneously, or watch one channel while recording another.

Bigger isn't always better - get a giant screen only if you have the appropriate viewing distance.

Calculate your estimated viewing distance from the screen to your couch in the room you are expecting to use for your home theater installation because that will determine how large a screen you should install and still get excellent image quality. Bigger is not necessarily better. If you get too large an HD display, and you sit too close to it, you may find the image soft i.e. blurry, or grainy and pixilated. You should sit no closer than twice the diagonal screen size for true HDTV images. Put another way, if you estimate you'll be sitting 10 feet from the video display, then a 60-inch (5 feet) diagonal screen size with HD programs is the largest you should consider. If you are closer, get a 50-inch diagonal screen. Existing DVD resolution will look better from farther back, and Standard Definition broadcast TV looks best viewed up to three times the diagonal screen measurement. For front projectors, that means sitting 16 feet back from a 96-inch screen with HD sources; and greater distances for DVD and regular broadcast TV.

Consider a front projector only if you plan to watch your movies or TV programs in a darkened room.

Front projectors for HDTV have seen significant price drops excellent HD models are available for $2000 to $3000US but whether they use DLP or LCD technology, they still have to throw light 10 to 20 feet across a room to create a big-screen image, so that image is intrinsically going to be dimmer to your eyes unless the room is dark, like a movie theater. If you have ambient light in the room, or prefer watching your movies with a room light on, the blacks, contrast and shadow detail will suffer. That's a compromise lots of viewers are willing to make because you can still get a huge image--96 to 120 inches diagonal is common. If that's the case, get a DLP front projector. They are capable of throwing a remarkably bright image. Because they're so compact (projectors are about the size of a major city's yellow pages), both projectors and screens can disappear completely into the ceiling when not in use.

If your room can't be totally darkened and you don't want to compromise on image quality, then consider a DLP or LCD rear-projection set (or LCD's cousin, LCoS). Those sets are available in screen sizes up to 73 inches diagonal and they will deliver a brilliant, high-contrast HD image in rooms that have ambient light. (Rear-projection sets get their blacks from the fact that the inside of the box is closed to light. Hence no internal reflections of light hit the screen, so blacks appear truly black. Rear-projection sets only have to throw the image a few feet inside their cabinet to the self-contained screen so they are intrinsically brighter than a front projected image.)

Although the newest flat-panel plasma and LCD sets are the most contemporary, sexy looking and least intrusive of new HDTV displays because they're so thin (about 3 to 6 inches), they are also the most expensive for a given screen size, typically costing $1500 more than the same screen size in a DLP or LCD rear-projection set. So if you are on a budget and you have the room, forget the flat-panel plasma and get a 50-inch or 60-inch diagonal 720p DLP or LCD rear-projection HDTV for $1800 to $2500, respectively.

Finally, if dollars are really scarce, don't ignore the vacuum tube (CRT) video display. Admittedly it's a fading technology and limited to about a 36-inch diagonal maximum screen size, but it's proven over half a century and is capable of excellent picture resolution with vibrant colors and inky blacks. There are still a few digital models available at prices below $1,000. The downside, of course, is that these CRT sets are large and heavy, with a 34-inch weighing in around 200 pounds.

Whichever HDTV set you get, consider having it professionally calibrated for optimal picture quality or do it yourself with a special test DVD like the Avia Guide to Home Theater or the Sound&Vision Home Theater Tune-Up DVD.

Repeat after me: There is no best, there is no best. A common sense guide to the HDTV display technologies:

As much as we all want to buy the best video display and be proud of it, there is no perfect TV display technology that satisfies all criteria. Each has its own virtues and drawbacks.

Here is a bottom-line guide to all the popular video technologies, with comments:

Plasma flat-panel:

Capable of bright, detailed, high-contrast images with very good blacks in a normally lit room. Viewable over a wide horizontal angle and can be wall-mounted. Slim (from 3 to 6 inches thick, depending on screen size) but fairly heavy 80 pounds and up for a 42-inch is typical. Subject to burn-in of a ghost image if left too long with a static logo or image on-screen. Some are power pigs, using up to 400 watts or more. Put your hand above the unit to see how much heat it generates that will give you an idea how efficiently it uses power. Commonly available in diagonal screen sizes from 37 inches to 60 inches, the latter size being very expensive, from $15,000 to $20,000US.

LCD flat-panel:

Very popular in screen sizes of 37 inches and smaller (recently, however, a few manufacturers offer LCD panels as large as 46 and 55 inches diagonal, with appropriately large prices, starting at $6,000US). Capable of excellent detail and color, with blacks that are fair to good, if not quite the equal of the best plasma screens. Generally more limited viewing angles than plasma, but new models are getting better. May be subject to image lag with fast-moving horizontal figures (e.g., a hockey player skating down the rink), which leave a ghost-like trail behind them because the LCD pixels don't turn on and off fast enough. View some fast-moving sports to check for this.

Generally run cooler and use less power than plasma panels and are not subject to burn-in of screen images.

DLP rear-projection:

Digital Light Processing sets use a bright lamp that shines against a postage-stamp-sized Texas Instruments-invented Digital Micro-mirror Device that's coated with millions of tiny hinged mirrors that create the image together with a fast-spinning color wheel, projected onto a self-contained screen. Capable of very bright, high-contrast ultra-sharp images with vibrant, rich color, excellent blacks and average but not great shadow detail (though newer sets are getting better). Very good value for larger screens (50 inches and up), with prices starting well below $2,000US. Color wheel may produce so-called rainbow effects visible to some viewers as brief flashes of rainbow colors seen in dark scenes with bright streetlights. Most viewers never see them but a tiny minority (less than 3%) can't watch DLP. Have family members view DLP set to make sure no one is sensitive to rainbow effects. Projector bulbs ($250 to $400) require replacement every 3,000 to 8,000 hours of viewing, depending on usage patterns and brightness settings. One exception: Samsung's $4,000 HL-S5679 DLP 56-inch rear-projection set that uses an LED light engine to eliminate the spinning color wheel (therefore no rainbow effects). The LED light source longevity is specified at 20,000 hours, roughly 14 years given average viewing habits. DLP sets are typically about 13 to 21 inches deep, for screen sizes beginning at 42 inches up to 73 inches diagonal. Not subject to burn-in of screen images.

LCD rear-projection:

Uses three LCD panels (for red, green, and blue) through which a projector bulb shines to generate the image that is projected onto a self-contained screen. Capable of vibrant, bright, rich and detailed images with good blacks that are close to DLP, if not quite their equal, although newer models with auto-iris devices improve contrast and blacks. Like DLP, the projector bulb requires periodic replacement depending on usage and brightness settings. No rainbow effects but some models have a visible screen-door effect (like looking through a screen door) because the pixels are not as close together as the mirrors on a DLP chip. This effect is only visible if you sit too close to the screen and only bothers some viewers. Observe my recommended viewing distances and you'll rarely if ever see them.

LCoS rear-projection:

Liquid Crystal on Silicon is a variation of LCD technology, first marketed by JVC and later refined by Sony in its SXRD and Qualia models. Similar to LCD but capable of improved blacks, contrast, detail and freedom from screen-door effects. Typically more expensive than LCD rear-projection sets. Immune to image burn-in.

Front projection (DLP, LCD, LCoS):

DLP, LCD and LCoS technology is also available in front projectors for use in darkened rooms with a separate big screen. These compact, affordable (starting at $2,000US) HD projectors can be ceiling-mounted and all use projection bulbs that require more frequent replacement (typically 1,000 to 3,000 hours) because the bulbs run hotter and brighter in order to throw an image onto a large 96 to 120-inch screen across the room. All have adjustable zoom lenses and focus, many with handy remote controls of the latter functions, although the zoom ranges do have limits and you must check your screen and projector placement with the manufacturer's specs to make sure the unit will throw the desirable image size in your particular setup. Advantages and disadvantages of these different technologies basically parallel those of the DLP, LCD and LCoS rear-projection sets noted previously, except that with a separate screen you can see a clear, bright image from any angle in the room. Three-chip DLP front projectors with no color wheel (thus no rainbow effects) are available at very high cost ($15,000 and up).

The last decade has brought a wide range of video choices to the market, all of which are capable of producing stunningly beautiful high definition images. Hopefully this article has helped you find the best set for your viewing preferences.

You panic! Is my new receiver defective? Is the hookup wrong? Maybe the surround levels need adjustment? Aren't these new multipolar surround speakers supposed to be all enveloping, immersing me in an involving and realistic soundfield? Did I position them incorrectly?

I answer email questions about this all-too-common scenario every week. The last query was from a user whose new A/V receiver wouldn't switch into the Dolby Digital mode, and refused to display Dolby Digital on its front panel. He also was disappointed with what few surround effects he could hear.

The truth of the matter is he wasn't hearing any surround effects at all--because his new A/V receiver wasn't operating in Dolby Digital 5.1! He was listening to the movie in stereo because he hadn't set up the DVD player's menu to output a 5.1-channel Dolby Digital bitstream, and he hadn't connected the DVD player's digital output jack to the A/V receiver's digital input.

Now, here's how to do it correctly (the following instructions assume that you own a Dolby Digital/dts 5.1 to 7.1-channel A/V receiver with digital inputs and a DVD player with a digital output jack, either coaxial or optical or both):

1. Connect your DVD player with either a single digital coaxial or optical digital cable from the DVD player's digital output jack to the digital input that corresponds to the DVD input on the A/V receiver. There is no difference in sound quality between these two types of connectors. Your DVD player may have only one type. If it has both, use whichever one is convenient. (There is no need to connect the analog left and right audio cables to the A/V receiver except in special circumstances.) Note: While you are at it, do not forget to connect the video cable, because the DVD player's digital output does not carry the video signal.
   
   
2. The next step is crucially important. DVDs do not necessarily default automatically to Dolby Digital 5.1. Each time you load a DVD, go to the DVD's setup menu and click on "Audio Setup" or on "Languages" if there is no Audio Setup option and choose "Dolby Digital 5.1." (If you have a 6.1 or 7.1 system select "Dolby Digital EX" if it is an available option.) Depending on the age of the disc, the "Audio Setup" on the DVD menu may give you several choices: "5.1 Channel Surround Sound" or "Stereo Playback." If it's an old DVD, it might even say Dolby AC-3 (the professional designation for Dolby Digital 5.1). New DVDs may offer "Dolby Digital 5.1" and "Dolby Digital 2.0," the latter being stereo. A sampling of my own DVDs, which date back to 1997, show all variations. Some of the disc menus offer only "Surround Sound" or "Stereo" options.
   
   
3. You should now see "Dolby Digital" displayed on your TV screen or on the display on your receiver. If this does not appear, you may need to go to the DVD player's menu and set the bitstream for Dolby Digital. You will need to refer to your DVD player's owner's manual to find out how to set this for your machine. Note: Fortunately this is a one-time set-up.
   
   
4. The single digital cable connector--either a plain coaxial cable with RCA male plugs on each end or a Toslink optical connector--carries the entire Dolby Digital 5.1(and dts if its available) -channel data stream to the receiver. It also carries a digital "flag" that signals your A/V receiver's Dolby Digital 5.1-channel decoder to switch to its Dolby Digital mode and send the multichannel audio signals to your system's six speakers. When it detects the digital flag, the receiver front panel should display "Dolby Digital" or indicate it with an LED or with text on the TV screen.

Another thing to remember: Dolby Digital is the world standard for 5.1-channel DVD movie surround soundtracks, digital cable-TV distribution and for satellite broadcasts of movies and programming. DTS is only an option for the producer of the DVD or music disc. The Audio Setup menu may or may not list dts, depending on whether or not the disc's producer decided to offer a dts soundtrack mix in addition to Dolby Digital 5.1. Lots of older DVD music videos do not include a dts soundtrack. Dts soundtracks are separately mastered and may have a different tonal balance from Dolby Digital. Many older first-generation DVD players do not read or pass a dts signal.

Once you have properly connected the DVD player's video and optical or coaxial digital cables to your receiver, go to your receiver's remote or front panel and turn on the Test signal that cycles a pink-noise signal consecutively through the left front, center, right front and the surround speakers. Make sure you hear the test signal from each speaker. Now adjust the levels carefully either by ear or with a sound-level meter from your listening location (much more accurate adjustments are possible using a separate sound-level meter such as the Radio Shack meter, available at modest cost with either an analog or digital display. It's a worthwhile accessory for accurate home theater channel-level adjustments).

Finally, check the polarity of all your speaker connections, making sure that the red and black speaker outputs on your receiver match the red and black connectors on each speaker. That will ensure that all the speakers operate in phase, with all of the drivers' diaphragms moving in and out together.

Do not rely on some new A/V receivers' auto-phase or auto-equalization circuits or on test discs that utilize microphones. Many are erratic in operation, indicating that some speakers are out of phase when in fact they are not or suggesting that adjustments are needed to alter the frequency response. The auto-EQ or interactive test discs will make good, neutral speakers like Axioms reproduce the unnatural response that has been electronically created and greatly deteriorate your home theater enjoyment. Use these circuits to adjust the channel levels only, then turn them off.

As a final reminder, don't forget to go to the DVD menu and click on Audio Setup and 5.1-channel surround sound every time you load a DVD. You've paid for all those multiple channels of sound reproduction, and you deserve to hear the movie the way it was mixed.

If your room has typical dimensions—20 x 14 x 8 ft., about 2,100 cu. ft.—one well-designed subwoofer with an internal amplifier equal in size to the full output of your receiver (full power for 1 channel + 1/8 power x the number of other channels) and a 10-inch or 12-inch driver should deliver solid deep bass extension and ample output for music and movie soundtracks.

On the other hand, if the room is larger than usual (4,000 to 8,000 cu. ft. or bigger) or has a vaulted or cathedral ceiling, you should definitely consider running an extra subwoofer.

Big rooms, especially the "great rooms" so common in many suburban homes, really devour deep bass, so two subs will generate enough sound pressure to fill the place. They'll also give you smoother distribution of extended bass over several different listening locations. My colleagues and friends who have large vaulted-ceiling rooms all run dual subs. Taste plays a role as well. If you like your music or soundtracks really loud and deep, go for two subs. If you have a huge room and you want really loud sound and deep bass, then look at physically larger subwoofers with bigger amplifiers, like the Epicenter EP600.

There is no specific need for two subwoofers to be identical in terms of brand name or physical size, but don't use a small, cheap sub with a large, good one.

As to setup, try the subwoofers in opposite corners (diagonally) of the room, one in the front and one at the back, with an initial crossover setting of 80 Hz and the rear sub phase switch on 180.

If the subs are too boomy in the corners, move them away from the corners along one wall or the other until you get smooth coverage of deep bass from the main seating areas in the room.

Another recommended placement for dual subwoofers is on opposite end walls in the middle of each wall, or on opposite side walls in the middle of each wall. There is no magic formula for subwoofer placement: experiment with locations, because every room is different. But be on the lookout for "nodes," which are areas in the room where there will be way too much bass, and other areas where you will hear little or none. The idea is to tame these nodes so you get uniform output in most of your important locations. If you have a choice, square rooms are the worst for nodes; irregular or rectangular shapes are preferable, and as you move couches or chairs closer to walls, bass intensity will increase. Conversely, the middle of the room will have less bass intensity.

Read the next tip: "Subwoofer Level Adjustments"

On the other hand, for consumers shopping for a new HDTV display, the following can be useful to identify video artifacts and decide if the subtle flaws might bother you. Keep in mind that none of the new HD or ED video display technologies (LCD, plasma, DLP, or LCoS) is perfect. Each has its own subtle video flaws, often specific to the display technology in question. But once you know what to look for, you can decide for yourself if a particular video artifact will prove distracting.

By way of explanation, a “motion artifact” is sometimes easy to spot. Here's an example from the movies, and you'll see it in any movie transferred to video as well. You may recall watching Westerns and seeing the spokes on fast-moving wagon wheels turning backwards or sometimes remaining motionless. This is a motion artifact of film, caused by the film frame rate—24 frames per second—not synching with the "rate" of the wagon-wheel spokes. When the spokes are in sync with the frame rate, the wagon wheel seems motionless; when it goes out of sync, the spokes start rotating backwards or forwards as the wagon slows down or speeds up. It always occurs and though we may notice it, it doesn't spoil our enjoyment of the movie.

With video, all sorts of different video artifacts may occasionally appear and many are related to motion. For example, all LCD flat-panel displays or LCD rear-projection TVs and LCD front projectors may show “motion trails” visible behind an object moving quickly across the screen—a car, roller-coaster, or hockey player. It's a subtle blurring or smearing and it's due to the inability of the LCD display's liquid crystals to switch quickly enough to follow the fast motion. It will affect all LCD TV display technologies to a greater or lesser degree and it may or may not be bothersome to you. If you really have to hunt to see it, then you can assume the TV display has it well under control or that you are simply not sensitive to it.

A related test for motion artifacts that may affect any type of digital HDTV display that uses digital video noise reduction is “motion adaptive noise reduction.” Most digital TVs use video noise reduction that may be turned ON or OFF at the viewer's discretion. However, if the noise reduction is inferior or too aggressive, it may confuse random noise (video grain) with motion, causing image smearing or motion trails behind fast-moving objects. If you only see it occasionally or not at all, then don't worry. If it seems gross, then check out a different brand or type of display.—A.L.

Read the next tip: "How to Manage Video Connects"

When it comes to determining at what height the main surround speakers should be mounted, “above ear level and to the sides of the listening area” goes only so far. Because each Axiom QS8 or QS4 uses four drivers, for a total of eight, they are remarkably forgiving of less than perfect placement, in part because there is lots of multi-directional energy being radiated into the room. Nevertheless, if you have a few minutes and a couple of assistants (or a pair of stepladders), some experimentation is always worthwhile. Try placing the QS surrounds at different heights and listen to them. Depending on your particular room's acoustics and surface angles, as well as the ceiling height, you may hear differences.

In my experiments, I've certainly heard differences, and while they are quite subtle, you may find that you have a preference for having the QS surrounds at a certain height. In my installation, what seems to occur is a slight shift in focus of the surround-sound field. You can't really say that one height is better than the other—it's just different. I found that with some DVDs or music recordings, the spatial presentation—the “space” which the music inhabits—changed somewhat when I increased the height of the surrounds. As to details, the bottom of my right surround is 5 ft. 10 inches above the floor; the left surround is one foot lower. If you are able to locate both left and right surrounds at the same height, I would advocate that. My installation didn't permit it, but I didn't hear any difference worth commenting on when the two surrounds were not at identical heights.

The point is to experiment before you install the brackets for the surrounds. Differences may emerge in your particular room and you may prefer a particular height.– A.L.

Read the next tip: "How to Manage Video Connects"

Here’s how:

Move your subwoofer as close as you can to where you sit. If it’s a chair, move the chair aside and place the sub where the chair was. If it’s a couch, slide the couch temporarily out of the way and put the sub about where you usually sit.

Play a DVD with lots of low-frequency effects or a CD with plenty of deep bass, the kind that really kicks your sub into motion.

Now the action. Get out the kneepads and crawl about the room in the general area where you were thinking of locating the sub. Go several yards in each direction—near the wall, out from the wall, towards a corner, away from the corner, and so on—while you listen for smooth and extended bass response.

At some locations, the bass may seem really exaggerated and boomy. In other spots, it may almost disappear. Pick a location somewhere between these extremes. That’s it! Mark the spot (no, not like a dog or a wolf would!), then move the subwoofer into that position. Now put the furniture back.

Test the technique by playing the same deep bass selections, only this time sit in your favorite chair (where the subwoofer was). The deep bass should sound just like it did at the place where the sub now sits.

You see? It works. And I hope you noted any dust bunnies while you were at it.

Read the next tip: "How to Eliminate Hum"

So where do you set each control?

To keep your receiver's LFE output level from overloading the input stage of your subwoofer amplifier, and to keep noise levels below audibility, adjust the receiver's LFE/subwoofer output level to "0 dB", and leave it there. When you do your level checks, start with the sub's volume control at about the 10:00 a.m position, then use that control to set or trim your final subwoofer level. And of course you may have to vary it somewhat depending on which source you're watching or listening to—CD, DVD, VCR, or off-air TV. However, except for some bass-heavy CD or DVD programming, the sub level shouldn't require much re-adjustment.

A visitor to the Axiom message boards was recently contemplating sawing a chunk out of his 24-inch wooden stands in order to “get the tweeters of his M22ti bookshelf speakers exactly at ear level.” While positioning bookshelf speakers so that the tweeter is roughly within a reasonable visual line with your head or ears is recommended, such drastic action with a saw usually isn't required. The high-frequency radiation of the 1-inch titanium-dome tweeter used in the M22ti, M2i and M3ti bookshelf speakers (and all of Axiom's speakers) is wide and consistent. Our "listening window" measurements of frequency response show that the tweeters' off-axis response at 15-degree angles is very similar to the on-axis response. Reflections from room surfaces will significantly widen the listening area beyond the anechoic measurements in most rooms. So you don't need to absolutely align the tweeter with your ears. According to Ian Colquhoun, Axiom's founder and chief designer, the speaker's frequency balance will not begin to audibly change due to the speaker's dispersion characteristics until you are beyond a 30-degree angle away from the front of the speaker.

This raises the issue of what height stands to use. In most installations, at a reasonable listening distance of 8 feet or more, using 16-inch or 24-inch-tall stands with the M3ti, M2i, or M22ti's only raises (or lowers) the soundstage. If you use your speakers in a home theater setup, you also want the front speakers' sonic soundstage to be reasonably consistent with the visual image, so consider the relative height of your video display when you select speaker stands for bookshelf speakers. I have found no significant difference in the transparency or quality of the sound using 16-inch or 24-inch stands. But personal preference also comes in to play. For reasons I've never fully understood, I don't like sitting in balconies, looking downwards on a performance or performers. I'm more accustomed to being seated on the main floor of a theater, watching the performers on a stage at the same level or slightly higher up. Even as a teen-ager (apart from the balcony hi-jinks), I never liked looking down at a movie screen. Consequently I like the soundstage even with or a bit higher, and 24-inch stands accomplish this.

Finally, if you worry about large dogs or toddlers knocking over stand-mounted bookshelf speakers, Axiom's new line of FMS metal stands use a clamping mechanism that won't mar the speaker's finish. Older stands can usually be modified to hold the speakers in place on the stand by using a non-marring adhesive putty like Blu-Tak or museum putty underneath the speaker.

Got a problem getting a smooth, seamless soundstage from your left main speaker across the center channel to the right speaker? Does much of the image seem collapsed into the centre? First, carefully adjust the center-speaker distance and level in your receiver's setup menu. Many enthusiasts run the center too loud. Adjust the center level loud enough so dialogue intelligibility doesn't suffer, but no louder. Try placing your main speakers so their front panels are even with the center channel, with the center channel further back, if possible (wall-mounting it behind the TV is another alternative). If the three main channels form a gentle arc facing your couch, with the center speaker the furthest away, you should experience a significant improvement in the forward soundstage.

The short answer is that it isn't a very good idea. It's inconvenient because the person in the bedroom or den won't have control of the volume or the source unless an elaborate system of infrared repeaters or some variation on custom wall plates with level controls is installed. However, for party purposes, if you simply want to pipe music into another room, it can be done if you work out the total impedances. Whether or not your receiver will even drive the extra speaker pairs depends on whether or not you want to run three pairs of speakers at once, power one remote pair, or run two pairs simultaneously. Running two or more pairs of speakers wired in parallel (red to red, black to black or + to +, - to -) simultaneously from the same amplifier may lower the combined impedance (resistance) to a very low value (4 ohms or less). Many receivers may overheat and temporarily shut down.

But you can apply a simple formula to calculate what will happen to the impedance when you power more than one pair together. The rated impedance of a speaker represents the combined resistance, in ohms, of the speaker (the voice coils inside, and the crossover) to the flow of current from your amplifier. If you power two pairs of 8-ohm speakers connected in parallel (see above), the amplifier sees a combined resistance of 4 ohms. That seems counter-intuitive, but that's the way electrical current behaves. Some A/V receivers will drive the 4-ohm load without difficulty but most will not.

Now, let's say you want music in your basement office. When you connect a third pair of 8-ohm speakers to the same amplifier that's already driving two 8-ohm pairs, you run into real problems. The equation for figuring out the total impedance (Rt) when the impedance of all speakers is the same (8 ohms in our example) is the impedance divided by the number of speakers. So for three pairs of 8-ohm speakers driven together, the answer would be 8 divided by 3 = 2.6 ohms, too low for any receiver to handle. When there are varying impedances amongst the speakers then you need a common denominator: 1/R1 + 1/R2 + 1/R3 = 1/Rt where Rt must have a 1 above it to be correct. If you had one 6-ohm pair, one 8-ohm pair, and one 4-ohm pair, and you wanted to run three pairs simultaneously, then the calculation would be: 1/6 + 1/8 + 1/4 = 4/24 + 3/24 + 6/24 = 13/24 = 1/1.85, so Rt = 1.85 ohms. If you try to drive all three pairs simultaneously with a 1.85-ohm load, the receiver will overheat and the protection circuits will temporarily shut it down to prevent damage to the output transistors. However, if your receiver has a speaker “A” or “B” selector (sometimes it's called “Main” and “Remote”), you can set it to drive one pair on A, and one pair separately on B, but not A and B at the same time.

There are a couple of other options. With many newer 7.1-channel receivers, you have the option of designating a second “zone” to drive a second pair of speakers in a bedroom or den using the two amplifiers normally assigned to the extra pair of rear-channel speakers that make it a 7.1-channel system. That way, there is no additional impedance load to worry about. Just set the receiver for “7-channel stereo” or a similar mode and rock away. And some models do let you wire up an infrared repeater and use a second remote in the other room to control the 2nd-zone volume. You could also add an outboard A/B switch to enable selecting one pair or the other (but not both at once) or use a multiple-speaker selector switch from Radio Shack or other suppliers. These prevent the impedance from falling too low, although these waste amplifier power and may introduce other impedance oddities.

If you really want to wire up many rooms in the house, then you have to use a distribution amplifier and control system that may contain 12 or more amplifier channels. Connecting up such a system is beyond the skills of enthusiastic amateurs, so things get very expensive because you have to call in an expert A/V installer. Frankly, it's simpler and far less costly to just get an inexpensive extra receiver and CD player or integrated amp for the second room, or a simple shelf system for the bedroom. You can upgrade the sound quality by substituting a pair of Axiom M3ti bookshelf speakers for the crummy ones supplied with the shelf system. It won't play as loud as your big home theatre system, but at least family in other rooms can choose their own programming without the hassle and expense of controlling it all from a central source.

Read the next tip: "Acoustical Room Treatment"

You might worry about running 30 feet or more of cable from the receiver at one end of the room to the speakers at the other end, but think about this: The voice coil of the woofer (the bass driver) contains more than 100 feet of fairly thin wire, much thinner than your speaker cables. It’s that thin wire in the woofer voice coil plus the wire in the tweeter’s voice coil (probably 20 feet or so) and the wires in the crossover that comprise the speaker’s impedance. With most domestic speakers, that’s nominally about 8 ohms or, in some designs, 4 ohms. The 'nominal' refers to an average impedance since the actual impedance varies with each frequency.

There isn’t any way you can lower the impedance of your speakers—that’s set by the designer and the voice coil windings. But you don’t want to waste power by using speaker cable that’s too thin. If it’s really thin (22-gauge or thinner), it can actually change the sound of the speaker. Taking a conservative view, you can keep your speaker cable resistance to 0.2 ohms or less by using 12-gauge cable in all domestic installations, even if your cables are more than 50 feet long. For lengths of 25 feet or less, 14-gauge cable is perfectly fine. There’s no audible benefit to using thicker cable, because the resistance of your cables is already insignificant, well under 5% of the speaker’s resistance.

Read the next tip: "Subwoofer Placement Tips"

Hum is a constant low-frequency buzz, usually at about 60 Hz or 120 Hz, which results from voltage differences between true "ground" (what you'd get shoving a copper pipe into the ground) and the electrical "ground" of your receiver's chassis, the incoming cable-TV feed, or any video or audio components interconnected within your system, including powered subwoofers. When this voltage differential exists, it's called a "ground loop," and the hum it produces is darned annoying. You'll hear the hum mainly from the subwoofer because it's a low-frequency noise, but there will also be hum from your floorstanding front speakers or even compact bookshelf models.

First, try disconnecting your subwoofer from the coaxial sub cable from your AV receiver but leave the subwoofer turned on. Does the hum go away? If it does, then the ground loop is entering the system from your AV receiver and/or your cable-TV system set-top box (or satellite dish and decoder).

Disconnect the incoming TV-cable or satellite feed to a set-top box or to your TV and the A/V receiver. If the hum disappears (and you don't use a satellite dish) complain to the cable-TV company. They may know what you need and supply you with a ground-isolating transformer. If they don't know what you are talking about you'll need to order a video ground isolator and install it in-line with the TV cable before it enters your set-top cable-TV box.

Before you order one, you can try plugging your subwoofer into a different AC outlet in the room, ideally one that is not on the same circuit as your AV receiver and video equipment (TV, DVD player, sat or cable TV box, etc.) That may solve the problem. If it doesn't, see if the back panel of your sub has a "ground-lift screw". It will be labeled as such. Just remove it. That may remove the hum. If it doesn't and you have a standard cable-TV feed (not a dish), then order the ground-isolation transformer.

Axiom Audio Ground Isolator

If that still doesn't eliminate the hum, or if you use a satellite dish video feed, then you could try one of these from Radio Shack, which goes between the subwoofer and the coaxial cable from the receiver's subwoofer output.

With persistence, all ground-loop problems can be solved.

Read the next tip: "Do I Need Two Subs?"

Back panel view showing color coding of pre-outs (left) and speaker binding posts (right).

A good idea, but you'll need the following color code to identify each channel unless you have your owner's manual handy. If your receiver has been manufactured in the last couple of years, there's a good chance it will conform to the new color scheme. In addition to the speaker binding posts, the RCA preamp outputs, the Subwoofer Output, and the multichannel analog preamp inputs also conform to the same colors.

For speaker binding posts, the negative terminal (-) is always black, whereas the positive terminal (+) will have a different color corresponding to each channel of the surround system. If you find this confusing, note the positive (+) and negative (-) polarity for each pair of binding posts. The new color code is:

Front Right speaker: Red
Front Left speaker: White                       
Center Channel: Green
Left Surround (side): Blue
Right Surround (side): Gray
Left Back Surround: Brown
Right Back Surround: Tan
Subwoofer Line-Level Output (RCA): Purple 

It’s mostly a result of oxidation of the internal metal moving parts within the potentiometer or switch, but dust certainly gums things up as well. You needn’t think these parts are wearing out. They’re not. They just need cleaning and de-oxidizing. And what better time than the advent of Spring to clean those controls? There are special sprays intended for exactly these chores. The contact cleaners I’ve found effective include ProGold GxL and Cramolin Special Spray, both from Caig Laboratories (www.caig.com), and Stabilant 22. Another similar product is Tweak. I’ve tried RadioShack’s TV Tuner and Control Cleaner, but I’ve found its cleaning effect is very short-lived, whereas the other cleaners will keep controls noise-free for years before you have to do them again.

The trick is to get at the noisy control. You have to disconnect your receiver or preamp and remove the bottom plate and perhaps the metal enclosure. These sprays come with a tiny tube that let you insert the end in any opening in the offending control. A quick spritz is sufficient. Do it while you rotate the control back and forth. Some selector switches may have a mechanical link from the front panel to an actual switch mechanism elsewhere inside the preamp or receiver. Just follow the link and spray briefly into the mechanism while you operate the switch. That’s it.

The tonal changes that occur are generally insignificant but in some unique cases they can be quite audible. A large number of enthusiasts don't recognize this, and tend to blame the speaker for any tonal differences that in fact may result from the interaction of the speaker with the room, the face of the TV picture tube or screen, or nearby surfaces.

The VP100, pictured in Boston Cherry

Several interesting emails from Axiom owners got me experimenting with this phenomenon. Knowing that the tonal balance between either a VP100, VP150 or the VP180 is excellent with our front-channel bookshelf and floor-standing models, I decided to put the matter to a test and try to find an undesirable location for the center channel. The good news is that a bit of fiddling with center speaker placement can restore the tonal balance if you should detect any imbalance between your VP100, VP150 or VP180 and your Axiom main speakers.

To document how center-channel tonal balance changes with different locations, I set up an experiment using an A/B comparator and my trusty sound-level meter, doing listening comparisons with the Axiom VP100, VP150 and VP180. I was also interested in discovering whether certain center-channel positions sounded more natural or better than other positions.

The results are fascinating: Changing the center-channel location will certainly determine how neutral or transparent your center channel loudspeaker will sound, and how well it will tonally blend with your main left and right speakers.

The VP150, pictured in Black Oak

(During this discussion, you should keep the following in mind: Moving any speaker will alter its perceived tonal balance relative to where you are sitting. This has been scientifically documented and supported by data gathered in tests conducted over many years at the National Research Council (NRC) in Ottawa, Canada, the facility where Axiom continues to measure and audition initial speaker prototypes. There, every speaker is auditioned in four different locations, and each listener rotates listening chairs, so by day's end, all listeners have heard each speaker in four different positions and from at least four different seating locations.)

In my first test, I connected the Axiom VP100 and VP150, placed on a 16-inch stand well out from my TV monitor, one center beneath the other. All the tests were done with both M80ti's and M22ti's as the main left and right speakers. With the loudness levels perfectly equalized, I switched between them using pink noise, movie dialog (male and female) and a variety of different music, with an emphasis on vocals. I also switched to pure stereo to compare the tonal quality of the vocals in stereo against the same signals through the VP100 and VP150. The similarity between the two was astonishing. I could barely distinguish them except for a slightly fuller sound from the VP150.

I put the VP150 on top of my TV monitor and left the VP100 on the stand in front of the TV. Now the two centers sounded quite different from each other, and the tonal differences remained when I exchanged the positions of the two speakers. Was it just the location that produced these different tonal balances and the different location relative to my ears?

It was indeed, because when I moved the VP100 from its stand and placed it on top of the VP150, the two centers again matched extremely well and blended seamlessly with the M22's or the M80's. I reversed the positions again, with the VP150 on top of the VP100. The tonal match was excellent. I also tried the two centers beside each other on top of the TV. The two center speakers sounded somewhat different again, with more noticeable timbral differences between the centers and the main speakers.

The lesson in all this is that if you detect noticeable tonal differences between your VP100 or VP150 and the main left and right speakers and you find those differences audible or distracting then it's time to experiment with placement. Try different locations, even sliding the speaker slightly to the left or right on top of the TV monitor, even if it isn't exactly symmetrical. Some Axiomites have found great success putting the center almost on the floor or on a short stand with the center angled up towards the listening area.

For improved center channel sound coverage or use with a large screen and a front projector, try two center channel speakers, one above and one below the screen. That way, for most viewers, the two centers running in parallel will image the dialog in the center of the screen, rather than too far above or below the screen. This dual center-channel formation will also reduce the effect of the location on the tonal balance.

Although most conventional forward-firing speakers don’t direct their audio frequencies as narrowly as a flashlight beam, they still are directional to a degree, depending on the frequencies of sound. Very high treble is quite directional, and plenty of midrange sounds, where most voices reside, are as well. It’s easy enough to demonstrate this effect by just standing in front of your center speaker and walking well off to either side, or "off-axis," as it’s termed. You’ll hear the midrange and highs become less detailed and voices become a bit dull. Detail and intelligibility are among the prime requirements of any center-channel speaker. If you seem to have trouble understanding movie dialogue, first increase the volume of the center channel with your receiver’s speaker setup menu, and then try these remedies:

If the center channel is on top of a big TV, it may be well above the height of the seating area, so get a couple of rubber doorstops (one Axiom owner used hockey pucks) and wedge them under the speaker base at the rear so the front of the speaker fires directly towards the listening area. Axiom’s center channels have broad horizontal dispersion, but it’s always a help to have the speaker aimed toward the listeners. And if your center speaker is on a shelf beneath the TV, angle it upwards towards the seating area. In large movie theaters the center channel is behind the center of the screen and carefully horn-loaded to direct the dialogue over a broad horizontal angle and a narrow vertical one, to avoid sound bouncing off the ceiling, which can inhibit clarity. Likewise don’t position a center channel more than 18 inches above the TV display or recess it in any way on a shelf in an entertainment unit. Move it forward and angle it downwards.

At its root, “bi” means “two,” and it relates particularly to the Axiom M80 and M60  tower speakers, which come with an available option to add “biwiring terminals.” Biwiring in practice means running two speakers cables to each speaker (a total of four to a pair of speakers) instead of one cable per speaker.

If you choose this option, then on the M80's rear panel (and the M60's), there are four binding posts instead of the usual two. One pair of binding posts is linked to the woofers, and the other two are connected to the midrange and tweeter section of the crossover. When the speakers are shipped, there are gold straps that run between the two pairs of binding posts, linking them so that they function electrically as a pair.

If you remove the gold metal links, however, you can biwire your speakers, using one speaker cable for the woofers, and the other cable for the midrange and tweeters. At the other end, both cables connect to the same amplifier output terminals. The practice became popular in Britain (not unknown for its eccentric audiophiles), the thinking being that using separate cables for low and high frequencies would somehow reduce interference between the two and improve sound quality.

If you look at the amplifier as a current source, then for amplifiers and receivers that are capable of supplying lots of current into low impedances, biwiring could offer theoretical advantages, particularly to loudspeakers that are linear and smooth, like the Axiom M80ti and M60ti, by eliminating potential intermodulation distortion between the low- and high-frequency portions of the audio signal. Using biwiring, this distortion would not occur because the low-frequency part of the speaker crossover would draw the current it needs for the woofers (and they need lots of current) through one speaker cable, while the midrange tweeter section would draw less current (it doesn't need as much) through its own speaker cable. This could prevent intermodulation distortion that may occur using one big “fire hose” or single speaker cable. (Using two cables per speaker will also lower total resistance to the audio signal—and that is well and good, although a single run of 12-gauge cable to each speaker will keep resistance to an insignificant level, well below 0.3 ohms.)

Will it sound any different if you biwire? Some users think it does, but I've never heard any differences, nor have any of our laboratory measurements or scientifically controlled double blind listening tests ever demonstrated there are audible differences. Axiom includes the extra terminals as a nod to those enthusiasts who believe that biwiring results in audible benefits and for the bi-ampers.

Bi-amping, or biamplification, is used mainly in professional sound reinforcement applications, where extremely high levels of loudness are required. Here big, separate amplifiers powering the low frequencies, and smaller amps for the midrange will increase overall output. Sometimes they will use a separate outboard electronic crossover (the speaker's internal crossover is disabled or bypassed entirely) so the operator can vary and adjust individual crossover frequencies, tailor the “slope” of the crossover to match the strengths of each set of drivers, and also adjust the relative sonic balance of bass, midrange and treble to suit the environment. This is important for huge auditoriums or outdoor events where separate arrays of treble and midrange horns are operating with big “bass bins,” but such systems have no place in domestic home theater systems in normal rooms. Additionally, it puts control of the relative smoothness and tonal balance into the hands of the sound system operator, a dangerous tool for all but the most experienced sound reinforcement experts. It also partly explains why the live sound at so many concert events (not all, mind you) is so awful.

No matter what the age of your TV, the first thing you can do is determine if there is an automatic circuit that controls flesh tones, and turn it off. While these circuits are a convenience, they automatically convert any color that approaches Caucasian skin tone to a uniform shade of peach. This introduces fundamental inaccuracy in reproducing all the other colors in the spectrum. So find that control and turn it off. You may have to occasionally adjust the Tint (hue) control for skin tones when you change channels, but in my view that’s a small sacrifice to make in order to achieve fidelity of every other color.

The next step is to calibrate contrast (white level), black level (brightness), hue (tint), saturation (color), and sharpness. Most manufacturers set up new TV sets for an extremely bright, contrasty picture. They do this so the sets will look good in bright, fluorescent-lit stores where customers will choose the TV set with the brightest, high-contrast picture as being the “best.” Start by turning down the Color (saturation) control so you’re looking at a black and white picture. Now adjust the Brightness control so you can still see detail in white areas. Then play with the Contrast (white level) control so that blacks are truly black but there remains a bit of detail visible in shadow areas. You may have to go back and forth between these two controls until you get a satisfactory black and white picture. Now you can adjust the sharpness so you get sufficient detail but not so much that any video noise or grain is obtrusive.

Next, turn up the Color (saturation) so colors are natural and vivid but not excessive. Finally, readjust the Tint (hue) so the skin tones look natural. If you have done this successfully, your set should properly render the full range of human skin tones from ebony black, through chestnut, to dusky hues and every shade of pink.

In the quest to get smooth, well-balanced sound reproduction in our homes, the one component we often ignore is the listening room itself. When speakers are accused of being "too harsh or too bright" or "too dull," it’s often the reflective or absorptive traits of the room’s furnishings and décor that are shaping the speakers' sound rather than any intrinsic problem with the speakers.

The majority of loudspeakers designed for home listening have their tonal balance adjusted so they’ll sound smooth and natural when heard in living rooms that are "typically" furnished: rugs or carpet on the floor, upholstered furniture, curtains of some sort, and bookcases on at least one wall.

But in rooms with tiled floors, with walls of exposed glass and bare brickwork, an otherwise well-balanced speaker may have too much midrange and treble energy bouncing about the room. With midrange and treble sounds, these surfaces react like mirrors and light, reflecting the high-frequency energy from a speaker.

A treble control or equalizer can be of some help, but a better approach is to add some area rugs, curtains and perhaps a wall hanging or two to break up and absorb some of the high-frequency energy. Upholstered furniture helps a lot, and hutches and bookcases will break up and dissipate sidewall reflections. The thicker the carpet and underpad, the more the absorption of reflected treble and midrange energy. Taming the reflections of a bare room can go a long way to getting that ideal balance of deep bass, midrange, and smooth highs that we all want from our speakers.

Read the next tip: "Repairing Scratched CDs and DVDs"

But as TV sets and the sources and delivery of video signals have become more sophisticated and varied (DVDs, satellite dishes, HDTV, videotape, and digital signals), so have the connections. Nowadays, there are four types—composite, S-video, component and digital—with the first three being the most common. If you have an aging VCR, it likely has a composite video connector, typically a single RCA jack. It’s called "composite" because it combines the color and luminance (brightness) portions of the video signal into one signal, so you only need one cable. But that combining of brightness and color portions lessens the video quality somewhat, so a new connector was introduced in the 1980s. The S-video jack ("S" stands for separated) keeps the luminance and chrominance (color) information separate, and this connector will usually yield significantly improved picture quality (compared to a composite connection) from sources such as DVD. The S-video connector also uses a single cable and a special plug.

Greater improvement is possible with DVD images by using a component video connection. Component video further separates the color and brightness information, using three cables from which the TV set extracts the red, green and blue components that make up the picture (plus the brightness or luminance). This type of connection must be used for TV displays and DVD players that have progressive-scan capability, and typically there are three separate RCA jacks. For high-definition (HDTV) video signals, a wide-bandwidth component-video connection is required.

The latest video connector found on recent HDTV sets is pure digital, called either a DVI (Digital Video Interface) or HDMI (High Definition Media Interface). These keep the video signal in digital form until it reaches the TV display. Read more about these interfaces.

Your TV display and DVD player must each have compatible connectors in order for you to benefit from the potentially improved picture quality. If your DVD player has component-video output jacks but your TV lacks them, then you can’t realize the benefits until you get a new TV that has component-video inputs. If all your equipment has S-video connectors, then use them.

Read the next tip: "How to get a Seamless Soundstage"

Dolby Pro Logic II (DPLII) is a digital matrix system that simulates a 5.1-channel output from any 2-channel analog or digital stereo source, including CDs, cassettes, LPs, MP3s, old Dolby Surround videotapes or any other stereo source. The latest “x” version of DPLII (DPLIIx) uses matrix technology to add one or two more surround channels (6.1 or 7.1) at the rear.

Dolby Digital EX (Extension) adds an additional rear center channel to the standard 5.1 channel Dolby Digital format by using matrix technology to extract rear-center channel information. However, the format is not considered a true, discrete 6.1 or 7.1 channel system because it lacks the capability to support a discrete 6th channel like the competing DTS-ES format, sometimes included as an optional soundtrack on DVDs.

Dolby Digital Plus is an enhanced discrete digital surround system developed for future use on High Definition DVDs. It offers increased bitrates (up to 3 Mbit/s), support for more audio channels (up to 13.1), improved coding techniques to reduce compression artifacts , and backward compatibility with existing Dolby Digital 5.1-channel hardware.

• Do I need to buy a DVD player with a built-in Dolby Digital/dts 5.1-channel decoder?
• How do I upgrade an old speaker system to a home theater?
• Which surround sound speakers should I get? Bookshelf or Tower Speakers?
• Do I still need a subwoofer with the floor standing tower speakers (M60 or M80)?
• Direct-radiating or quad polar speakers for the extra 2 speakers in a 7.1-channel system?
• Will the QS8 rear speakers work well for music playback?
• Which TV display technology is best? LCD or Plasma?

Speaker Placement and Set Up

• Speaker Delay: How to Set Up Surround Sound Speakers?
• What speaker distance and height should I use for my speaker set up?
• Stereo Speaker Placement: Where to Put M3 Bookshelf Speakers?
• Speaker Placement: Are the M80 Floorstanding Speakers Hard to Place?
• How to Connect Subwoofer to Receiver? Subwoofer Connection Questions
• Where do I set the crossover control on my subwoofer's back panel?
• How high up on the walls should I mount surround speakers?

Audio Knowledge

• Searching for the Best Speaker Sound: What does "speaker accuracy" mean?
• Maximum RMS power of M80s?
• Why is "delay" important for DVD-Audio or SACD surround music systems?
• No Surround Effects with Dolby Digital Content?
• What are "balanced connections" and the benefits of balanced cable?
• A/V Receiver Power - Leave Off or On?
• HDTV Resolution and Pixel Count?
• Subwoofer Phase Switch
• What does the ".1" stand for in Dolby Digital and dts multichannel surround sound?
• How much better is 6.1 or 7.1 channels than a standard Dolby Digital 5.1-channel setup?

Q. My question may sound stupid, because I'm just a beginner in audio/video. Do I need to buy a DVD player with a built-in Dolby Digital/dts 5.1-channel decoder? And if so, must I also buy an A/V receiver with a built-in Dolby Digital/dts decoder? Or would this be redundant? -- G. F.

A. There is no such thing as a stupid question when you're trying to 'decode' audio! No, you don't need a DVD player with a built-in Dolby Digital/dts decoder because virtually all modern A/V surround sound receivers already have internal Dolby Digital/dts decoders. The DVD player just needs to pass the Dolby Digital or dts data stream to the receiver via a coaxial or digital optical cable, and even the least expensive DVD players will do that. So it would be redundant to get a DVD player with built-in decoders (there is an exception: see below).

DVD players with built-in decoders are for use with older equipment that won’t decode the digital 5.1-channel surround formats. For example, you might have a couple of old stereo amplifiers (or an old Dolby Pro Logic receiver) you wanted to use in an inexpensive Dolby Digital 5.1-channel home theater setup. As long as your old amps or receiver have line-level inputs for each amplifier channel, you could cobble together enough amps to feed the front left and right, center, and two surround channels. The DVD player with the built-in decoder will have six analog output jacks, one for each channel. Then you’d need to add a powered subwoofer for the ".1" low-frequency effects channel. You’d use the DVD player’s internal menu to do the proper setup for your speakers. It would be inconvenient adjusting overall volume levels, but it would work, and you’d save the cost of a new Dolby Digital/dts A/V receiver.

But if you want playback of DVD-Audio or SACD multichannel audio discs, the DVD player must have a built-in decoder for these formats because there are no receivers that will decode them (the record labels fear digital piracy so they won’t provide digital outputs). Such DVD players almost always include Dolby Digital/dts decoders as well.

Back to top.

  Q. When you allude to the "accuracy" of Axiom speakers, what exactly do you mean? I’ve looked around for a good definition of accuracy but there seem to be many. What is the definition you are using? -- Mike B.

A. Well, at Axiom we mean the speaker reproduction is as close as possible to the original recording or performance. Though this may sound fundamental, it's surprising how few speakers are designed to this goal. From a
measurement perspective this generally translates into a "linear" response. The speaker should evenly reproduce deep bass, upper bass, midrange sounds (including male and female vocals) and treble high-frequency sounds, neither exaggerating nor suppressing any segment of the tonal range. If you drew a graph of a speaker’s response to every sound audible to the human ear, it would ideally be a straight horizontal line (hence the term "linear").

We actually calculate the way an Axiom speaker responds to sound by putting it inside an anechoic chamber (a room with no echoes), feeding it tones representing every frequency audible to humans--from the deepest bass at 20 Hz to the highest frequencies at 20,000 Hz--and then measure the speaker’s output with a microphone, graphing the results on a chart. An accurate or linear speaker’s output should approximate a smooth horizontal line, free of peaks or valleys in response. This would represent accurate reproduction of every frequency audible to the human ear and would be the speaker’s "frequency-response curve."

Since these same measurements can be performed at various axis degrees which
causes them to change, the real designing comes in understanding the relationship of the entire "family" of curves and their eventual overall effect on the listening performance.

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Q. I have an older stereo system with bookshelf speakers. How do I upgrade this system to a home theater? What should I add next? -- A.C.

A. Besides getting an A/V surround receiver with Dolby Digital/dts 5.1-channel decoding, you could start by getting a center-channel speaker and two surrounds, using your existing bookshelf speakers as the main front channels. Although you may have some tonal differences between the center and your older bookshelf speakers, you would still be able to enjoy full 5-channel home theater, albeit without the deep bass impact that a subwoofer would bring with the ".1" channel. Depending on your budget, I would next add that all-important subwoofer, because part of the thrill of current DVD soundtracks are the deep bass music and sound effects.

Assuming you’ve budgeted for the DVD player and A/V receiver, another approach would be to retire your existing bookshelf speakers to the role of surround speakers, and, depending on the room size, replace the front left and right speakers with modern floor standing or bookshelf speakers. You needn’t get a center channel immediately (although I consider it fairly essential) because the movie dialogue will be roughly centered between the main speakers so long as you don’t sit too far to one side. Later on, add the center channel, the subwoofer, and, if you want a more enveloping sound field, a pair of bipole/dipole multi-radiating surrounds.

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Q. I have two QS8s in the rear corners of my room. I’m confused by the speaker setup menu in my Yammi RXV 1300 receiver. When it asks how many feet away for the QS8 surround speakers, is it asking the distance from the mains, or how many feet away from my listening position? I believe this deals with delay? How is this done?--Dan

A. The Yamaha speaker setup menu is asking you the distance in feet between your listening position and the QS8 surrounds. The reason you must set this correctly involves compensation for a peculiarity of human hearing--our tendency to locate a close-up sound before one that’s a little farther away. The receiver digitizes all the incoming signals for each channel and inserts an appropriate degree of digital delay so that the sounds radiated by the two surround channels reach your ears after the sound from the center channel and the main speakers. Since in many installations, the surround speakers will be closer to the listening area than the main front speakers or center channel, our ears would normally detect the sound from the surround speakers before that from the main speakers, which would totally throw off the illusion. So by entering the distance from your chair to the surround speakers, the Yamaha inserts enough digital delay so you will hear the sound from the main front speakers first, then that from the surround speakers. (Sound travels at about 1 foot per millisecond, so it’s easy for a digital circuit to apply the appropriate amount of delay.)

It’s a kind of precedence effect that’s important in real life because it helps protect and alert us to nearby events that might be threatening. (If a car horn beeps to your right as you step off a curb, you immediately glance there and take steps to avoid being run over.) But with multi-channel surround sound, the illusion only works if the sounds from nearby surround speakers reach your ears after the sound from the main front speakers.

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Q. I am planning on adding a pair of M80tis to my system. What is the maximum RMS power that they will handle? The web site states that the minimum and maximum amplifier power for the M80ti is 10 watts and 400 watts, respectively. Am I to assume that the 400 watts would be max RMS? Thanks for your time. -- John

A. The loosely agreed-upon standard for measuring the power handling of a loudspeaker is five hours of modified pink noise without damage to the speaker.The basic problem with this test is it does not address the dynamic nature of music and movies. The instantaneous peaks of the dynamics are really what is going to determine when you run out of amplifier power and where the speaker will hit its limits. At Axiom, we conduct both tests using pink noise as well as dynamic tests to create the maximum amplifier power rating for each Axiom speaker. In the case of the M80s, they have been tested a minimum of five hours using modified pink noise at 400 watts rms from the amplifier. Furthermore, they have been tested at this level for 100 hours using highly dynamic source material. We keep the ratings conservative, i.e. the tests are actually done at 600 watts for a 400-watt maximum power rating. In fact, the M80s have been tested up to 1200 watts without any problems.

Many people think their speakers may be damaged if they connect them to amplifiers with power-output ratings that are far in excess of the speaker's stated limits, or that they should somehow "match" the speaker's maximum power rating to an amplifier. However, unless you truly abuse your speakers by running them at excessive levels where distortion becomes audible and grating, even small speakers can be used with little or no risk with quite large amplifiers. It is in fact small amplifiers driven beyond their dynamic capabilities (clipping) that cause the most damage to loudspeakers.

You should also scrutinize the "sensitivity" rating of a speaker because this is a standard adhered to by most manufacturers. It tells you how loud a speaker can play for a given input signal level. The sensitivity rating is the sound pressure level (SPL) measured in decibels (dB), produced by the speaker at a distance of 1 meter, with 1 watt of input power. The M80 will produce 95 dB SPL (in room) and 91 dB SPL (anechoic) at 1 meter with 1 watt of input power. That is very loud sound, and because the M80 is this efficient, it can be driven to reasonable listening levels by a 10-watt amplifier. As speaker sensitivity goes, the M80s are at the high end of the scale. However, keep in mind that all of these SPL ratings are done at 1 meter and as you move farther away from the speaker, substantially more power will be required to achieve the 95-dB rating. In very large rooms, a lot of quality amplifer power is required just to achieve reasonable volume levels.

More compact speakers like the M2i produce 91 dB SPL (in room) and 87 dB (anechoic) with 1 watt of amplifier power, so they actually need more, not less, amplifier power to produce comparable sound levels. It is important to be aware that loudspeaker acoustic output in decibels does not double each time you double the rms amplifier power. For instance, if a speaker requires 10 watts to produce a comfortable listening level from 12 feet away, doubling the amplifier power to 20 watts would only raise the speaker's sound level by 3 dB. Subjectively, 3 dB sounds "somewhat louder," but it's nowhere near "twice as loud." To achieve that would require ten times as much amplifier power, or 100 watts! So the old adage of buying as much power as you can reasonably afford still applies. We will be covering a lot more detail on all these relationships in the upcoming newsletters.

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Q. What should the distance be between the two front speakers in a stereo or home theater system, as well as between the two surround speakers? I also want to know at what height I should mount my surrounds? Thanks. -- Adi N.

A. Start by separating your front left and right speakers by about half the distance that you sit from the speakers. If you sit 12 feet back, separate the front left and right speakers by about 6 feet. You can vary this formula quite a bit. At 12 feet, I'd try anything between 5 and 8 feet. Use enough separation between the two speakers so you can easily perceive the stereo effect and directional cues without getting the sense that the sound is emanating from two separate boxes at the front of the room. You want a smooth, seamless, stereo soundstage.

In home theater systems, this is much easier to achieve with a center-channel speaker (except when you are listening in 2-channel stereo, with no center running), because the center-channel speaker nicely fills in the middle. But even here, aim for an unbroken soundstage.

If you get a hole-in-the middle effect in stereo, then move the two mains closer together or toe them in slightly towards your listening position until you get a seamless soundstage in front of you.

There are no cast-in-stone rules about speaker placement other than avoiding corners (except for a subwoofer). Experimentation is the key. You can see some suggestions in our Audio/Video Tips section.

As for surround speakers, just remember the way surrounds are positioned in any Dolby Digital cinema--on the side walls, to each side of the listening area, approximately opposite each other and well above the level of your ears. Dolby Labs says that you can also move them slightly to the rear (up to 20 degrees) or a bit forward of an imaginary line drawn across the listening area. Axiom's multidirectional QS8 or QS4 surrounds are very flexible in this regard, and needn't be at the same height or distance from the listeners.

If you are running a 6.1-channel or 7.1-channel system, the additional rear surrounds should be on the rear wall, not the sides, at about the same height as the side surrounds. Do not aim or angle any of the surrounds down toward the listening area. The purpose is to create an enveloping surround soundfield.

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Q. I keep seeing criticisms on audio forums of the new DVD-Audio and SACD high-resolution audio formats that suggest that "they have no bass management or delay." I know what bass management is, but why is "delay" important for DVD-Audio or SACD surround music systems? -- M.B.

A. One of the most acute abilities of human hearing is our knack for instantly sensing the direction and intensity of specific sounds. If we lacked this ability, there wouldn't be much fun in stereo or home theater multi-channel surround sound, and more important, this directional hearing ability plays a huge role in self-preservation.

Our precise stereophonic hearing acuity results from near-instantaneous calculations performed by our brain when it measures the difference in timing of sounds that reach one ear and the length of time it takes the same sound to round our head and reach the other ear. Called "inter-aural time differences" (IAT), these immediately tell us which direction a sound comes from. Inter-aural amplitude (loudness) differences combine with the timing differences to give us our finely-tuned multi-directional hearing ability.

If you think for a minute about virtually any installation of main front speakers and side- or rear-located surround speakers, you'll realize that in most rooms, the surround or rear speakers are often closer to the listening area than the front speakers. By our laws of directional hearing (sound travels about 1 foot per millisecond), it's apparent that any sounds coming from loudspeakers close to the listener will be perceived before the sound from speakers farther away--the main speakers at the front. If a surround sound setup is to perform convincingly, the sounds emanating from the side or rear speakers must be delayed by 10, 15 or 20 milliseconds or more, so they arrive after the sound from the main speakers reaches our ears, otherwise your brain will tell you that the sounds are coming first from the surrounds and then from the main speakers and the whole illusion will collapse. (In mixing Dolby Digital 5.1 movie soundtracks, there are times when the director intentionally wants you to hear the sound from, say, the right rear speakers first, as in a plane or spaceship that is to fly diagonally over the room and appear on-screen as it passes above us and moves on.)

The intrinsic flaw native to both DVD-Audio and SACD formats when they were first introduced was that there was no requirement for implementing delay of the rear channel sounds. Consequently, during demos, I found that if my seat was even slightly closer to a left or right rear speaker than the front speakers, that's where I heard all the sound coming from. It ruined the multichannel illusion. In my view, it was a huge technical oversight that is only now being corrected in the latest generation of new DVD-Audio and SACD players. Even the earliest analog Dolby Surround processors decades ago had analog delay lines for the surround channels, to ensure that listeners would hear those sounds after the dialog and sounds from the speakers at the front of the theater

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Q. My room is 19 ft. x 11 ft. x 8 ft. and I sit 8.5 ft. from the speakers. Should I use the QS4's or QS8's for my rears? My left/right separation for the front towers will be 5 or 6 feet. I like the M60's, but should I go for the M22s? Thanks. -- Phil L.

A. Given the size of your room and listening distance, you could certainly use the Epic Grand Master system, which uses the QS8 surrounds. The latter are a slightly smoother tonal match to the M22ti's or the M60s. By the way, the QS surrounds should go to each side of the listening area, per Dolby Lab specs, not the "rear". You can use them at the rear if you wish--they're very accommodating--but the side walls are preferred for a correct Dolby installation because that's how 5.1-channel movies are mixed, with the surrounds on the side walls of the listening area. See the diagram below for best placement. If you add the extra single speaker for a 6.1 setup, or additional two rear speakers for 7.1, the rear wall is the intended location.

The M60s have a somewhat "bigger" sound than the M22s and of course are capable of significantly deeper bass extension and output as well as higher, cleaner volume levels than the M22ti's. I use the M22s (with a sub) in a slightly larger room and they play as loud as I ever want. However, some of my younger friends and colleagues listen at levels I wouldn't dream of using! So think about whether you want to "crank" the system up with high-level rock 'n' roll. The tonal balance of each model is very similar, with identical midrange and upper-octave detail and clarity.

The QS4s are very good, but have slightly smaller woofers, so they won't play quite as cleanly at loud levels as the QS8s. The QS4s are more suitable for modest-sized rooms and lower power-output receivers.

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Q I have a dedicated listening room of 10ft 4in X 19ft 6in. What is the manufacturer's recommendation for placement of the m3ti's? Thank you for your time, - AAron

A The general guidelines for speaker placement apply to the M3ti's as they would to any compact loudspeaker: Keep them away from corners (which will unnaturally boost the bass output) and separate them by about half your listening distance. You want to achieve a smooth, continuous soundstage across the front with no "hole-in -the-middle" effect. The latter is a symptom of too wide separation between the two speakers. If you sit, say, 12 feet away, use about 6 ft. or more of separation between the two speakers. You can try angling them slightly in towards you (toe-in) or not.  Keep them out from the wall by at least a couple of inches, and feel free to experiment moving them farther away from the wall behind. Every room is different, and nearby boundaries may or may not interfere. Most bookshelf speakers sound their best when the top of the speaker is close to your ear level when seated. Usually stands of about 16 to 24 inches are about right.  More open, spacious sound is sometimes achieved keeping the speakers several feet away from the wall behind and side walls.

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Q. I own a set of M80ti's and have had no problems with placement. Why is it I see some people on the message boards (most don't even own M80's) say that these speakers are so hard to place? When asked "Where did you hear this," they say that Alan has said so. If this is true, why would they be any harder to place than any of the other speakers that Axiom offers?

A. I'm delighted you've had no placement problems. Readers sometimes repeat what I've said without mentioning the context in which I made the remarks.
My comments about the M80ti's relate to setting them up in smaller rooms where there isn't a lot of elbowroom to move stuff around. In slightly larger than average rooms or big rooms, the M80s are simple to place. I suspect you have a setup where you were able to keep the M80ti's out from the wall behind them and away from walls to each side. My comments also relate to the relative ease of locating bookshelf models like the M22ti's or M3ti's, which are small, lightweight, and easy to move. Any floorstanding speaker always takes a bit more experimentation in placement than a bookshelf speaker because the floorstander's deeper bass interacts with the floor and nearby boundaries more than bookshelf speakers. That's true of the M80ti's because they have very deep bass response and greater overall bass output than our other tower speakers. By contrast, bookshelf speakers like the M22ti's don't have much bass output deeper than 40 Hz, so nearby boundaries don't interfere as much. (I've told some customers that it's virtually impossible to make Axiom's M22ti's sound bad.)

The room's dimensions and furnishings are always influential, as well as how far back you sit from the M80s. In an average room like mine (19 x 14 x 9 ft.), jammed with other speakers and equipment, where I sit no more than 10 feet back, you can't just plunk M80ti's down and expect to get a perfect soundstage. You have to experiment, moving them away from corners, out from the wall behind them and adjusting toe-in. In my setup, I eventually got my M80s to sound excellent by putting them to either side of the large-screen TV, which is diagonally arranged across one corner of the room. The M80s are only 6 inches out from the wall behind (not as far as I'd like) but I seemed to have found a location where there are no significant interactions with standing waves in the room. I've been nudging the M80s into different locations in my room for a while now, and it's reassuring to discover that it is possible to get M80ti tower speakers sounding good in a smallish room.
Moreover, it's great to get feedback from owners like yourself who are pleased with the performance of their M80ti's in rooms of average size. -- AL

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Q. I have a Dolby Digital/dts A/V receiver but I don't hear any surround effects when I receive High-Definition TV programs from my satellite tuner. And when I play DVDs, I also feel there should be better surround effects. I thought "Dolby Digital" is supposed to be a big improvement. What gives? – R.H.

A. There are two issues here. In your case, you are assuming that every HD satellite broadcast will be in Dolby Digital 5.1-channel surround, and that is not always the case. It's true that "Dolby Digital" (DD) is the audio standard that's specified for HDTV, but broadcasters may choose from several Dolby Digital flavors: Just because it says "Dolby Digital" does not mean that a soundtrack is broadcast in 5.1 channels. There is also Dolby Digital 2.0, which means you will get digital sound but only in 2-channel stereo. Plenty of older movies or programs that were mixed in 2-channel stereo may be broadcast on HD channels in Dolby Digital 2.0. If your A/V receiver is properly configured, it will indicate that and let you switch to Dolby Digital/Dolby Pro LogicII, which will simulate a 5.1-channel surround format from the DD 2.0 soundtrack. Note that if the DD signal the receiver detects is Dolby Digital 2.0, the receiver may automatically default to "Dolby Digital + Dolby Pro LogicII" without your having to select it (my H/K A/V receiver does that automatically). If you press the Dolby Digital button on the remote, you can switch to DD 2.0 if you want, but you lose the surround channels and the center.

I ran a cursory check of HD broadcast channels I receive from Time-Warner's Digital Cable service and some were in DD5.1, others in DD2.0. Surprisingly, most of the High DefinitionTV sports broadcasts of basketball and football games are in Dolby Digital 5.1, even repeat HD broadcasts of recent games on InHD. Most DiscoveryHD programs are also in DD 5.1. An older movie on Showcase HD was in DD2.0, but some current drama series ("Charmed") was in DD5.1, as was a movie on HBO-HD.

If the HD broadcast truly has a DD 5.1-channel digital soundtrack, your receiver will detect a digital "flag" in the data stream and automatically switch to the Dolby Digital 5.1 mode. Your front-panel receiver readout or on-screen menu will say that and it will not let you change the surround format. (This assumes you are using an optical or coaxial digital audio connection from your HD tuner or your DVD player to your receiver. If you use only an analog stereo connection, the A/V receiver will replay the soundtrack in Dolby Pro LogicII or dts Neo6, or Logic7 if you prefer.) Be sure you select the correct digital audio input (optical or coaxial) for whichever source you are watching. Note also that dts is not part of the HD broadcast standard; you will get dts only from DVDs and dedicated dts multichannel discs, not from digital TV broadcasts. And dts is an optional soundtrack format; it is not a requirement on a DVD.

When you play a DVD, go to the DVD menu for your player, and click on Audio Setup or soundtrack preferences (sometimes you may have to click on "Languages" to get to the audio setup). You will have a choice of selecting Dolby Digital stereo or DD5.1, and in some cases, dts. Most DVD players will default to the stereo mode unless you select "Dolby Surround" or Dolby Digital 5.1. Now you can get ready to actually hear surround effects!– A.L.

Need more information? Read Alan's in-depth article on DD5.1 Setup

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Q. Some expensive A/V preamp-processors and power amplifiers offer "balanced connections." And the new Axiom EP600 and EP500 subs also have them. What are they, and are "unbalanced" connections inferior to balanced? What would I gain in performance using balanced connectors? – J.C.

Balanced Connector

Used almost universally in the world of recording studios and professional broadcasters, balanced connectors use a three-wire cable fitted with very secure and solid "XLR" connectors (sometimes called "Cannon" connectors). The three-wire balanced configuration is composed of an outer shield surrounding two out-of-phase inner wires that carry the positive and negative portions of the signal. This enables running very long cables--hundreds of feet if necessary-- between amplifiers and preamps or between microphones and a mixing console without picking up hum or interference and without significant signal loss.

Since long cable runs aren't required by most consumer audio/video installations, the simpler 2-wire "unbalanced" design and connectors are used—an outer shield that carries the ground (negative) portion of the signal plus a single inner positive ("hot") wire. This design is much less costly and, so long as cable runs remain relatively short, offers ample shielding and resistance to interference and signal loss. From a performance standpoint, an unbalanced amplifier or receiver is capable of excellent performance but may be more vulnerable to RF (radio frequency) interference as well as AC hum problems from "ground loops" and component interconnection. To the electronics engineer, a "balanced" system of inter-component connection is a technically more elegant design but considerably more expensive. – A.L.

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Q. Should I turn my A/V receiver off, or, like my computer, just leave it on all the time? Does it draw lots of power on startup causing undue strain over time? If I do leave it on, should I turn the volume to zero or is mute ok? Thanks. – I.Z.

A. This debate has been going on for years. It grew out of the vacuum-tube era of recording studios and early vacuum-tube computers, where there was good reason to leave tube equipment running all the time. Tube gear takes some time (hours or even days) for the circuits to stabilize whereas solid-state circuitry settles down in a few minutes or less. The surge of power to the tubes' cold heater elements also shortened tube life each time tube gear was turned on. But that just isn't true of solid-state gear used on an occasional basis--even every day--in domestic applications like home theater and music reproduction. The turn-on power surge for solid-state equipment has negligible life-shortening effects, given the remarkable longevity of modern transistorized components.

Unless you are running a recording studio 24 hours a day, it makes no sense to leave your A/V receiver on all the time. Heat is the enemy of all circuitry over the long term, and all components generate heat. This is especially true of A/V receivers, which jam seven amplifiers plus control circuitry onto one chassis. (Incidentally, the position of the volume control or whether the receiver is set to "Mute" is irrelevant.) If you want to see how much power you are wasting in heat when you leave the receiver on all the time, look up the "idling power consumption" in the specifications section of your receiver owner's manual. It will likely be at least 120 watts if it's a 5.1-channel (or more) surround-sound model. That's like leaving a 120-watt light bulb running all the time. And most A/V receivers nowadays have "Standby" circuits that use a tiny bit of power to keep the infrared remote receptor and circuit active, so you can use the remote control to conveniently switch the unit on or off.

In the days of abundant cheap electrical power 30 years ago, many TV sets had an "Instant On" feature (my old Sony Trinitron had it) that kept a low voltage supply to the picture tube's heater element so the TV didn't have to "warm up" for a couple of minutes. But most brands eventually dropped that feature as the cost of electrical power moved upwards.— A.L .

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Q. Regarding Alan Lofft's column entitled "Standard or High Definition: It's All in the Pixel Count," if I have a Samsung DLP HDTV that has a native resolution of 1280 x 720p and I'm watching HDNet, which uses a 1080i signal, there is no way I'm going to get the number of pixels that come with that 1920 x 1080i format . . . right? The native resolution on a set is the maximum number of pixels that can possibly be displayed? Also, do the 720p and 1080i figures refer to the horizontal or vertical number lines? Thanks. -- Patrick

A . The 720p and 1080i figures refer to the number of horizontal lines stacked vertically from top to bottom of the screen. Those are also called "vertical resolution." The 1280 and 1920 figures (called "horizontal resolution") are the total number of individual pixels (picture elements) across each of the horizontal lines for the 720p and 1080i formats, respectively. So it's true that in your example you won't get all 1920 pixels of HDNet's horizontal resolution from your Samsung's 1280 x 720p display. The Samsung DLP, a plasma, or an LCD panel are all "fixed-pixel arrays," and the Samsung's micro-mirror DLP chip has a native resolution of 1280 x 720p. Likewise, a plasma or LCD flat-panel will have a fixed number of pixels across each of its horizontal lines which may or may not exactly correspond with the transmission standard, just as the 1920 pixels that HDNet uses aren't an exact fit for the 1280 pixels of the Samsung DLP chip. But that doesn't matter because the Samsung or plasma set's internal digital scaler will automatically convert all incoming video to "fit" its native resolution. And in my experience the differences, if at all visible, are very tiny. The really visible differences occur between 480p and 720p, or between 480i and 1080i, the differences between Standard Definition and High Definition.

Moreover, the overall clarity of a DVD displayed on an HD set is affected by the original movie or program's aspect ratio, which may not be identical to the 16:9 (1:85:1 ) widescreen standard adopted for HD. If you watch some extremely widescreen movies such as "Lawrence of Arabia" (2:35:1), not all the pixels are used by the scanner during the digital transfer to DVD. Consequently, when you watch playback on your HD widescreen set, there will be black bars at the top and bottom of the image, even on a 16 x 9 display. This lessens overall resolution, because all the pixels used to display the black bars are not used for image display. Fewer pixels used for picture content equals lessened resolution. It's visible, but in my opinion it's not a big deal.

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What does the "Phase" switch on my subwoofer do? Do I set it to 0 or 180?

It synchronizes the in-and-out movement of your sub's woofer with the woofers in the rest of your system so that when the subwoofer cone is "pushing" air out, the other woofer diaphragms are also moving outward. If your subwoofer is on the same plane as your front speakers then set the subwoofer phase switch to 0. If your subwoofer is located anywhere else then try the phase switch in both positions and set it to the position that produces the strongest bass at your listening position. Given the vagaries of bass standing waves that result in all rooms, you may notice no difference at all, in which case set the switch to 0.

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2. What does the ".1" stand for in Dolby Digital and dts multichannel surround sound?

The ".1" channel -- and it is a separate, discreet sixth channel -- handles only the lowest frequencies present in movie soundtracks or multichannel music recordings. Technically, it's "bandwidth-limited," which means it carries bass frequencies of 100 Hz and lower, hence the ".1" designation. The remaining five channels of Dolby Digital or dts are full-bandwidth channels, carrying the full frequency range from 20 Hz to 20 kHz if no subwoofer is used. When you set the speaker designations in your A/V receiver's setup menu to "Small," the receiver's bass management system (a crossover) routes the frequencies below 100 Hz to the subwoofer (LFE) output jack. Most receivers let you choose the crossover frequency for the deep bass.

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3. How do I connect the subwoofer to my A/V receiver? I have one cable. Do I plug it into the subwoofer's left or right input, or both?

Use either the left or right line-level RCA jack on the subwoofer. You don't need to connect it to both, because the inputs are "summed" to mono inside the sub. Connect the remaining RCA male plug at the other end of the shielded coaxial cable to the single "Subwoofer Output" jack on your receiver. It might also be labeled "LFE Out" (Low Frequency Effects) or "Sub Out."

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If I get M60ti or M80ti floorstanding speakers for my left and right front channels in my home theater system, do I still need a subwoofer?

You can use the M60 or M80 without a subwoofer because both have smooth, extended bass output, but for movie soundtracks and home theater applications, the subwoofer produces lots of very low-frequency effects designated just for the sub, plus bass for the center and effects channels, especially when you have the Bass Management in your receiver set to "Small" for the center and surround speakers. If you set your main front tower speakers to "Large", the subwoofer will still handle deep bass dedicated to the LFE channel and the towers will cover bass that was mixed full frequency to the front left and right towers. Hence a subwoofer will greatly enhance your system's overall bass response. Reproducing bass, especially in a large room, can be quite a difficult task. The sub-woofer in conjunction with floorstanding front speakers will help a lot in accomplishing this goal. If you set your floorstanding front speakers to "Small" on your receiver you should set the cross over frequency for these to a lower level than the center and surround speakers, either 40 or 60 Hz would be best. Even in this small setting the floorstanding front speakers will add significantly to the power and efficiency of your systems bass output. The built in amplifier in the subwoofer will relieve the load on the amplifiers in your receiver. This also reduces distortion and results in cleaner sound overall because the amplifier does not have to "work" as hard. Don't worry that you will "waste" the deep bass capabilities of your main speakers. The receiver crossover gradually reduces the load on the main speakers as it transfers the low frequencies to the subwoofer, but your main speakers will still be producing significant output to 40 Hz or lower, and lots of upper bass

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Where do I set the crossover control on my subwoofer's back panel?

If you are using a Dolby Digital/dts A/V surround receiver with its own Subwoofer Output jack, and a single coaxial cable to your sub, then the subwoofer's internal crossover becomes unnecessary and you should turn the control to its highest setting (150 Hz) to effectively remove it from the circuit. Some brands of subwoofers may have a "Bypass" switch, which does the same thing. By doing this, you are avoiding "cascading crossovers," or using two crossovers in a row, which may cause losses or gaps in the bass response. The A/V receiver performs all the "bass management" and routes the appropriate frequencies to your subwoofer from the Sub Output jack, so the sub crossover becomes redundant.

If you are using your subwoofer for 2-channel stereo with an older 2-channel receiver or amplifier (non-surround sound), then you'd use the speaker-level input connectors on the subwoofer because in most cases the receiver or amp will not have a dedicated line-level subwoofer output jack. You must then set the subwoofer's own crossover to route the low frequencies to the subwoofer. Try a setting of about 80 Hz to start, depending on how large or small your main speakers are. If they are very tiny satellites, you may want to raise the crossover frequency to 100 Hz.

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How much better is 6.1 or 7.1 channels than a standard Dolby Digital 5.1-channel setup? Am I losing something by not adding the additional one or two back speakers?

The vast majority of movies are mixed for 5.1 channels--left, center, and right front channels with two side surround channels. Some more recent movie releases make use of the "6.1" capability, and more recent A/V receiver processors will extract extra information to feed a pair of extra rear speakers on the back wall even if the movie is just mixed for 5.1 channels. There is no question that 6.1-channel or 7.1 setups improve the sense of surround envelopment and also make for smoother and more convincing directional panning effects for side- and rear-mixed sounds, although the room will also influence the degree of improvement. Coverage of surround effects in larger rooms will definitely benefit from the extra surrounds at the rear, and using multipolar surrounds like the QS8 or QS4s will enhance these effects. Certainly there is no downside to utilizing the extra surround capability if the A/V receiver offers it.

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If I do add the extra two speakers at the rear for a 7.1-channel system, should I use direct-radiating speakers like the M2i or M3ti or the quad polar QS8s or QS4s?

In a general way, it's best to use rear speakers that are identical to the surrounds at the sides, although there is some controversy about this. Using identical surrounds at the sides and rear guarantees the same tonal balance and dispersion traits from all four surround speakers. However, many Axiom system owners report excellent results using QS8 or multidirectional surrounds at the sides and two direct-radiating M2i's at the rear.

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How high up on the walls should I mount the surround speakers?

If you are using multidirectional, quad polar type surround speakers like the QS8s, generally from 12 inches to 5 feet above the level of your ears when you are seated will often produce the best sense of surround envelopment. Multidirectional surrounds like the QS8s or QS4s tend to be very accommodating and "unfussy" as to placement and it isn't even necessary to have them at identical heights or distances. Every room is different, of course, and some experimentation with a couple of stepladders to support the surrounds while you listen is useful. With direct-radiating surrounds, higher is usually better, but keep them at least 3 inches away from the ceiling to avoid boundary effects from the ceiling.

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I love the sense of surround envelopment that I get from my QS8 multipolar surround speakers with movie soundtracks, but I've read that the new DVD-A and SACD multichannel music formats are mixed using direct-radiating speakers at the rear. Will the QS8s work well for music playback?

Most of us do not have room to install two types of surround speakers--multipolar types for movie playback and direct-radiating speakers for surround music playback. A few A/V receivers have outputs for two types of surround speakers to meet this need directly, but experience suggests that for many rooms and setups, a multidirectional-type surround will function admirably for movie surround or music playback. In real life, much of the ambient sound reaching our ears in clubs, auditoriums and concert halls comprises a rich mix of reflected sound, and given that most domestic rooms do not have the dimensions to generate this melange of reflections, a multipolar surround is the preferred choice. This subject remains somewhat controversial. However, if you have the budget and the space, then four or five identical tower speakers in very large rooms would duplicate the conditions under which these recordings are mixed.

You can have a "Home Theater" with a setup as simple as a TV set, a pair of stereo speakers, and a DVD player. But usually Home Theater consists of something a little more elaborate.

In fact, setting up a home theater can be entirely affordable. You likely already have at least one of the key elements-a TV set! So what else do you need and what exactly is the goal?

The goal is to duplicate, in your own home, the surround sound envelopment and integration of picture, drama, and sound that you experience in a commercial Dolby Surround movie theater, only on a smaller scale. The entertainment is for you, and your friends and family. That may sound ambitious, but surprisingly, even a basic home theater system can deliver remarkably enhanced playback of DVD movies, concerts, rental tapes and DVDs, and even TV shows like "CSI" or "Law and Order: Criminal Intent" or "Smallville" that are recorded and broadcast in Dolby Digital 5.1 Surround Sound. For example, you can enter this world with an Axiom Home Theater system for well under $1,500. (You already have the TV, and very possibly a DVD player or Hi-Fi VCR.)

A basic home theater system consists of a pair of front left and right speakers on either side of the TV, a center-channel speaker on top (or beneath) the TV set to anchor the actors dialogue at the TV screen no matter where you sit, a pair of smaller surround speakers to either side of your couch that carry all the effects and ambient sound of a movie or TV show-street noises, planes flying, jungle sounds, the noise of rain, thunder, or crickets, distant explosions or rumbles of tanks, and all the myriad of other sounds that make up a complicated movie soundtrack, including, of course, the movie score, the music and rock songs that underscore the action on screen. Lastly, most home theater systems add a subwoofer, typically a square black box that produces ultra-deep bass sounds-rumbles, storms, deep musical bass and the like.

If you've kept count, that's a total of six speakers, including the subwoofer, and it comprises "5.1-channel" sound (the .1 is the subwoofer bass channel). But all the speakers needn't be big. Because the subwoofer carries much of the low bass energy, the other "satellite" speakers can be compact and visually unobtrusive, no larger than a hardcover book.

To this mix, you must add a Dolby Digital Surround Sound Audio/Video receiver, which contains all the circuitry to "decode" the DVD or videotape movie soundtrack and effects, plus five built-in amplifiers for each of the five loudspeaker channels (the subwoofer always has its own dedicated built-in amplifier). And finally, you need a DVD player. (You can use a Hi-Fi stereo VCR, but it will only deliver analog Dolby Surround, not 5.1-channel Dolby Digital.) A DVD player is less than $100, and a Dolby Digital/dts A/V receiver can be had for $200 or more. To that, add perhaps $1,254 for an Axiom Epic Midi Home Cinema system, including the powered subwoofer. That's it - a complete surround sound home theater system. Dim the lights, micro the popcorn. Let the show begin!

Now you know what it is . . . so what do you need? Click here to send an email to our audio experts for a recommendation based on your room size and listening preferences, or contact us toll-free at 1-888-352-9466 for fast, free, friendly advice. 

And you do not have to have the income of the stereotypical movie mogul to put one in your house. In fact, in the same way that a striking kitchen renovation will raise the potential market value of any house, so too will a dedicated home theater room. Consider it as more than entertainment - consider it as an investment.

The Allocation

The preceding smooth talk is all well and good, but what kind of figures are we talking about? For example, how much money does it require to put in a 7.1-channel surround sound speaker system worthy of the High Definition large-screen display you're lusting after? In gathering facts for this article, I drew from a variety of sources, including an Axiom survey as well as from Axiom customers who provided me with a breakdown of their particular costs in converting and building dedicated home theaters in their homes.

The Axiom survey revealed that most people who might own or purchase a house priced between $150,000 and $350,000 judged that having a dedicated home theater room would add about $15,000 to $25,000 in value to the house. So using that figure, let's look at what sorts of equipment expenditures it takes to get started. Assume a slightly larger-than-average sized room with dimensions of about 25 feet long by 15 feet wide by 8 feet high around 3,000 cubic feet.

For a room that size, to get an impressive sounding 7.1-channel surround system coupled to a video screen or display of at least 50 to 60 inches (diagonal) or larger, figure on spending about $10,000 for the equipment. Here's a percentage breakdown of that $10,000 figure:

The Budget:

• 35 to 40% of the equipment budget to the 7.1-channel home theater speaker system about $3,500 to $4,000.
• 30% to 35% for the High Definition video display (rear projection, or front projector and screen, flat-panel plasma or LCD, plus associated controls) – $3,000 to $3,500.
• 20% to 30% for the electronics (AV receiver or AV processor and amplifiers, DVD player) – $2,000 to $3,000
• 5% to 10% for cables, wiring, and miscellaneous – $500 to $1,000

Let's analyze that further and put in an Axiom Epic 80/500 7.1-channel surround system that's $3,762 and that system will deliver a thrilling sonic experience with movie soundtracks or music. I ought to know: I'm old, experienced, and I've got one. And over the passage of 25 years of both writing for and editing audio-video magazines in Canada and the US, I've heard, tested and owned a lot of systems and loudspeakers.

Large-Screen Video

Now we add the video display. The entire television system of North American is gradually converting from analog to digital video, which includes high-definition TV (HDTV) and multi-channel surround sound. So we'll put in an HDTV, and in a room of those dimensions, we're looking at a 50-inch or larger screen, either rear-projection or front projection LCD or DLP. So add about $3,000 to $4,000. Now we still need the electronics the AV receiver/amplifier, DVD player. So figure on about $2500 for the AV receiver/amplifier, and DVD player.

There's room for lots of variability in how much you spend. For example, if you are content with a 50-inch diagonal DLP or LCD rear-projection set that has 720p resolution (720 progressively scanned lines is one of the two standard High Definition formats; the other is 1080i), then you can pick that up for $2500 or less.

Let's say you balk a bit at that $10,000 figure. Remember that's just for the equipment. The room, the seating, the décor, all of that is extra, and we've added on an additional $10,000 in our theoretical house for the room décor, seating, construction and labor.

Downsizing the Room

So how do you scale down your home theater somewhat? The easiest way is to simply make the room smaller, about 2,000 cu. ft. or less. You could convert an unused bedroom once the kids are out of the house (do they ever leave?), or a room above the garage. That way, you don't require big floorstanding front speakers and a less powerful AV receiver will suffice, and a smaller screen HD display. And you don't need 7.1 channels, which are more appropriate in bigger rooms, for better distribution of surround effects. A 5.1-channel system using multipolar QS8 or QS4 surround speakers will deliver excellent performance in the smaller room.

Consider a typical bedroom: 12 x 15 x 8 ft (about 1500 cu. ft). You could install an Epic Grand Master/500 system in a 5.1 configuration for $2460. You won't need as large a screen, either, so perhaps a 46-inch DLP will be ideal, and that's $1800. A good quality Dolby Digital/dts A/V receiver for that size of room is readily available for $500 or less. Throw in a high-performance but budget-priced DVD player for $200, and our total equipment bill is now $4960, plus a few hundred for wires and cables.

The movie and music experience will still be terrific, with the smaller room compensating for the smaller loudspeakers, lower power, and smaller screen.

Customer Experience

Now let's see what one Axiom customer actually spent to convert what was originally a screened room or Lanai ( Florida location) into a shared/dedicated home theater and music room.

Here is the breakdown:

Speakers (Axiom):

M80 Floorstanding Front Speakers
VP150 Center Channel
VP100 Center Channel
QS8s (4) Surround Speakers
EP600 DSP Subwoofer
Total: $4,550

Video Display:

Mitsubishi WD 73727 73-inch rear-projection DLP HD set: $5,000;
TV Stand, $500

Total for Surround speaker system and large-screen video display: $10,000.

Electronics:

Rotel RB 1080 power amplifier, $999
Harman/Kardon AVR635 A/V receiver, $699
Denon 2910 DVD player, $700
Sony CDP CX 355 CD 301-disc MegaChangers (2) $400
Elan IR Remote system, $278
Total: $3076

Room Construction Materials and Labor:

Approximately $7,000
Room wall plates/installation, RG6 cabling, Cat5, speaker wire:
$1100

Total: $8100

Grand Total: $21, 226

This owner spent around $14,000 for more elaborate audio and video equipment including a large Axiom EP600 subwoofer, two center channel speakers and a dedicated Rotel 300-watt-per-channel power amplifier for the M80 floorstanding speakers. Alternatively, he noted that he saved on labor costs by doing much of the work himself and considers the final cost of the room well worth it.

How do these amounts compare with our guidelines? As it turns out, quite closely. The original budget guidelines suggested allocating 35% to 40% of the $14,000 equipment budget to the home theater surround speaker system. Our real-life Axiom customer spent a bit less than 35% ($4550) on the Axiom 7.1-channel surround speaker system and exactly 35% ($5000) on the very large Mitsubishi 73-inch DLP rear-screen TV. That figure could be reduced by going to a smaller screen rear-projection DLP or LCD for instance, a 52-inch DLP or LCD HD set would likely run about $3500 or less.

Similarly, the Axiom home theater system could be reduced by a few hundred here and there by using an EP500 subwoofer and M60 floorstanders vs. the M80 towers and EP600 but overall, allocating about 65% of the equipment budget to the video display and 5.1 or 7.1-channel speaker system is entirely sensible.

The 50% suggested budget figure ($10,000) for the room construction, décor, and miscellaneous wiring and cabling also correlates well with the Axiom owner's real-life expenditure of his $21,000 budget, he spent $7,000 with an additional $1,100 designated to wall plates, installation, RG-6 and Cat5 cabling plus speaker wire, for a total of $8100. But he did much of the labor himself, so that figure was less than the suggested room budget.

Sky's the Limit

For homes worth more than $700,000, budget guidelines go out the window. The owner should simply spend whatever he or she wants, to get the room look desired. Plenty of homeowners love the mini movie theater look, with real theater seating, star motifs on the ceiling, curtains, popcorn machines and movie posters on the walls and lighting that automatically dims.

So there you have a number of alternatives to building your own screening room and playing Hollywood mogul. Once completed, the only decision you'll have to make is which movie to start with!

Prototype Axiom Heavy-Duty Component Video Cable

So how important is the speaker cable? To read some of the ill-tutored theories bandied about in some high-end audio publications, you’d think the writers thought little notes danced along the cables to your speakers, subject to degradation and all manner of hazards in their brief transit to the loudspeakers. Indeed, some exotic cable manufacturers claim that their overpriced wire will actually improve the electrical signals!

In fact, the flow of electrical signals through copper cable is rather straightforward. The voltage produced by the amplifier end is the driving force, like water pressure in a hose. When you turn the tap at the end of the pre-filled water hose, the water flows out the other end immediately. In a similar manner, the electromagnetic field that represents the audio signals transmits through the copper cables at about 90% of the speed of light.

Resistance The main impediment to moving audio frequencies through a copper cable is resistance,

Heavy-Duty Speaker Cable with Gold-Plated Spade Lugs

which results in a waste of power. If you use thicker cable, 16-gauge to 12-gauge (the lower the number, the thicker the cable and the less resistance there is), resistance can be kept to about 0.3 ohms or less, an insignificant value. For cables runs of less than 25 feet, 14-gauge cable is ample. For speaker cables shorter than 15 feet, 16-gauge is fine. Long runs of 25 feet or more require 12-gauge. You may run across fancy terms like "skin effect" and "transmission line." These have no bearing on simple speaker cables. Suffice it to say that such artifacts only become significant to telephone engineers stringing miles of cable.

With audio frequencies, which normally range to 20,000 Hz or higher, there are no losses of consequence in thick copper cables. Measurements conducted years ago at the National Research Council in Ottawa showed losses of barely 0.25 dB at 100,000 Hz with 12-gauge copper cables.

Connectors With all cables, you want bright, shiny connections at each end. The main reason gold-plated connectors are desirable is that they never tarnish. Copper may turn a dull brown or green after years, but a little sandpaper will restore the shine. Sturdy and well-made connectors are important here, regardless of type. Banana plugs, spades, pins, or bare wire can each make a fine electrical connection for speaker cables. It’s a matter of convenience and utility which you choose. Most good 5-way binding posts accept any of these.

Audio Interconnects The coaxial cables used to connect your CD or DVD player carry "line-level" signals of a couple of volts, much tinier signals than the amplified output sent to your speakers, so those interconnects must be shielded with a braided metal mesh to prevent induced hum and other interference from corrupting the tiny audio voltage. These shielded cables are called "coaxial" because of the outer mesh shield, covered with insulation, that prevents the intrusion of external hum and noise-inducing fields. Just as important are the soldered connections between the outer braided mesh shield and the connectors at each end. So examine the terminations closely. On high-quality cables you can unscrew the metal connectors to scrutinize the soldered connections. For vinyl enthusiasts, it’s important that the cables between the turntable and the receiver or preamp are low-capacitance, to prevent changes in frequency response.

Digital Connections What about digital connectors? For those who’ve wondered, there isn’t any difference in the digital audio signals conducted by a coaxial wire cable or a fiber-optic interconnect. In the former, the on and off pulses representing the binary code of a digital signal are conducted electrically; in the latter, a "Toslink" interconnect uses pulses of light to transmit the same code. Fibre-optic digital links are not subject to hum pickup or electromagnetic interference, a nice feature. But apart from that virtue, coaxial and optical digital connectors "sound" identical.

Video Interconnects

Professional Weight S-Video Cable

Video signals tend to be more fragile, especially over longer runs. Cables longer than 6 feet can wreak havoc through high-frequency losses, because video signals extend into the 12-megahertz range (that’s 12,000,000 Hertz!) for High Definition TV (HDTV). High-quality video cables are important, particularly when you are running component-video or S-video signals 15 or 20 feet to a projector. Because preserving video high frequencies correlates directly with the sharpness or clarity of the TV image, it makes sense to spend some money on good video cables so you can preserve the integrity of the video signals from a DVD or high-resolution source. Here again, connectors should be mechanically sound with a secure friction fit.

Finally, where do you find good-quality, mechanically sound, no-nonsense audio/video cables at a reasonable price? You order cables directly from Axiom. In the meantime, be suspicious of brands that use pseudo-scientific language to justify their high prices or make claims that defy the laws of physics. There's good reason some of those have been labeled "audio jewelery."

Now you know what the pros know, and with the money you've saved by *not* buying smoke and mirrors, you can double your CD collection!

If you are watching front projection images on a large separate screen and there is light in the room, you won't believe how much better your big-screen images will look—snappier contrast, blacker blacks and richer colors-- once you truly darken the room with blackout curtains. You can find them at places like Home Depot and they are inexpensive, available in several colors, and made from a velvet-like micro-fiber that shuts out all the light.

When ambient light falls on a projection screen, it washes out shadow and black areas, reduces contrast and apparent color saturation. “Black” in video terms is an absence of light. The pixels in the video device turn off and stop producing light or, in the case of an LCD front or rear projector, stop letting light pass through the LCD panel. A front projector's light output thrown across a room is much less than a rear-projection DLP, LCD or LCoS set, but even those sets will benefit from a significant reduction of extraneous room light.

2. Use the “Cinema” Brightness Setting for Serious Viewing

Owners of DLP or LCD rear-projection HDTVs may have noted their sets have several possible pre-set brightness settings (the brightest mode is usually reserved for demos in fluorescent-lit stores). In nearly all cases, you'll get the finest gradation of colors, skin tones and black levels when you choose the “Cinema” or dimmest mode. (This assumes you've already installed window coverings or blackout curtains to reduce ambient room light.) The projector bulb will also last longer when it's run at its dimmer setting.

3. Shop for more Comfortable Seating: Consider Dedicated Home Theater Chair

Don't make it too comfortable or you or your guests may doze off mid-movie, which is always embarrassing. But if, like me, you have an aging couch with sagging springs that prove to be uncomfortable after a one-hour program, then it's time to upgrade. It's the type of item that's likely been on your list for some time but you never quite get around to it. Do it. Besides, when the lights are up, you'll still have some great seating to collapse into at the end of a long day.

4. Upgrade the Center-Channel Speaker to Improve Dialogue Clarity and/or the Surround Speakers for Greater Effects Envelopment

We often cobble together a home theater system using an old bookshelf speaker of a different brand as the center. It's easy to become accustomed to the colorations that may exist because it's from a different maker and much older technology than your main speakers. But those colorations, tonal mismatches and lack of detail are what inhibit dialog clarity. If you've had trouble understanding dialog in DVD movies and TV shows, you'll get immediate improvement with a new center-channel speaker that has the same detailed, clear and transparent sound quality of your left and right front speakers.

Poor dialogue clarity may also result from a subwoofer that's turned up too loud. Powerful low bass at too loud levels has a tendency to flood the room with standing waves that overwhelm intelligibility, muddying up the dialogue and imaging. Balance is the key to a great bass experience: deep bass should form a foundation for great home theater sound but not dominate it.

Multi-directional QS4 Surround Speakers shown in Eggshell White

The closer the tonal match between the center channel, main left and right, and surrounds, the better your overall experience will be. Likewise, you may have used some older speakers from days gone by as “temporary” surrounds. Speaker technology improves on average every five years and great strides have been made in dedicated multi-polar surrounds that mimic the envelopment in effects you experience in a big cinema. So replace those aging surrounds with a dedicated effects speaker, preferably one that uses multiple drivers to enhance envelopment for all the viewers no matter where they sit. Adding two extra surrounds for 7.1 channels will also improve the sense of viewer envelopment and involvement.

5. Get Home Theater Speakers and 3-D Sound Quality that Match Your High Definition Video Display by Retiring that HTIB System

If you've been “making do” with that so-so Home-Theater-in-a-Box system and you've just gotten a new HDTV display, you've likely found that the sound quality no longer matches the stunning HDTV video images. It's time to retire the HTIB to a bedroom and get a really excellent dedicated 5.1- or 7.1-channel speaker system that delivers a high-fidelity three-dimensional audio presentation fully the equal of your big-screen HDTV display. You needn't do it all at once, either. Start with some high-quality front and center speakers, adding the surrounds and then a powerful subwoofer as your budget permits.

.1: Upgrade or Add a Powerful Subwoofer for Enhanced Movie and Music Enjoyment

Just like using some old speakers as a center or surrounds (see above), making do with a tiny bargain basement sub just won't cut it with your new big-screen display and high-quality main speakers. You may even have stopped noticing the one-note boom of the bass module. But you'll experience a real kick if you scale up the quality of the low bass effects with a powerful subwoofer. After all, Dolby and dts dedicate a low-frequency effects channel just for deep bass effects—and advances in technology like modern DSP-powered subwoofers (eg. Axiom's EP500 and EP600 subwoofers) will excavate bass far lower than ever before. Sure, make do with the old sub for a while if you want, but prepare for a dynamic lift in performance when you fire up a great, dedicated subwoofer.

Dept. of Cheap Thrills:

Those who would like a truly “moving” experience but don't want to annoy the neighbors or wake the kids may want to consider adding butt kickers or bass shakers to some of their home theater seats. While it's no substitute for real deep bass from a big subwoofer, a bass shaker is a tactile transducer, powered, that installs beneath the seating portion of a home theater seat and connects to a speaker or subwoofer output from your receiver/amplifier. The device tracks the low-frequency effects and vibrates accordingly, giving seated viewers a physical buzz. No sound is emitted. Prices for bass shakers start at around $200.

The first impulse is to try and hide speakers, or instead choose tiny inconspicuous cubes or orbs that house small little drivers (drivers are the cones and domes that move air to create sound waves). The impulse to hide speakers is generally one you should avoid. Sound quality will suffer drastically if you try and bury good speakers inside something else—special cubbyholes in custom cabinetry or the like. Speakers need to be open to the air they have to move in quantity, and they can't do that concealed in an armoire or from behind a fancy latticework wooden grille.

Nor are the unobtrusive little cubes a solution. The weak little drivers may work in a small den, but they can't begin to generate the big, compelling sounds of a full orchestra, band or movie soundtrack with anything approaching real fidelity.

So, how to solve this dilemma?

Here are five ways to get around this problem and keep all parties satisfied.

Consider a hybrid in-wall speaker with a finished real wood veneer trim that will complement rather than sully the furnishings and décor.

In-Wall/On Wall - Epic Master

While we don't suggest you get speakers that are concealed within the wall or ceiling, there is a real alternative that combines excellent sound quality with an attractive appearance: a hybrid in-wall speaker with an exterior finished frame and the bulk of the speaker enclosure inside the wall. It's precisely designed to duplicate the sound quality you'd get from a comparable bookshelf speaker. You will have to choose carefully where to install a hybrid in-wall, because holes will need to be cut into the wall. But once installed, the wiring can be routed inside the wall to the AV receiver, resulting in an almost invisible installation that sounds excellent.

Consider custom-finished beautiful real-wood veneered speaker enclosures.

If floorstanding speakers are recommended or required for bigger spaces and great rooms, go for custom-matched real woods that blend with and enhance the décor. You can order samples ahead of time and match the finish of the speakers to the decorator's or your partner's requirements.

For dual-purpose rooms, get an electric projection screen that's hidden behind a valance and descends when you want to watch a DVD or TV show in surround.

Depending on your lifestyle, space and budget, you may want to have your home theater be part of a central family room or living room, rather than having a dedicated theater room. It's not that difficult to accomplish. Quiet, smoothly descending electric screens with remote controls can be installed behind a valance finished to match the surrounding wall or woodwork. When you're in the mood for a DVD, a touch of a button lets the screen descend for viewing and retract out of sight at the movie's end. Modern DLP (digital light processing) or LCD High-Definition video projectors are so compact that they can be unobtrusively installed on the ceiling with the supply cables run inside the ceiling. Control of the projector is enabled with a remote that bounces off the screen surface.

Use the subwoofer as a nicely finished end table or support for a lamp or plant.

EP500 Cherry Natural - VaSSallo Series

Subwoofers the big boxes required for ultra-deep bass don't have to be ugly. You can order one in a highly attractive real-wood finish and locate it at one end of a couch as an end table to support a lamp or plant. The versatility of surround sound acoustics allows for the subwoofer to be placed almost anywhere in a room because we don't hear direction from low bass energy. So the subwoofer does not have to be at the front of the room near your front speakers, screen and video display. As often as not, it may in fact perform better at the side or the back of the room or, in some rooms, off in a corner.

Unlike good speakers, the electronics, DVD players and amplifiers can be hidden away in attractive custom cabinetry, a refurbished closet or a special niche in the wall.

The house wiring that powers your lights and appliances is hidden inside the walls of your home. In the same way, the versatility of modern electronics and cables lets you do that for the AV receiver, DVD player, and amplifiers that you'll need to power the speakers. You can house the electronics in custom cabinetry or a redesigned closet, so long as you add an accessory muffin cooling fan to ensure proper air flow. If you don't wish to display powerful separate power amplifiers for larger systems, they can be put out of sight in a cooler basement room with the audio-video processor/controller upstairs in the viewing area.

It's always frustrating to newcomers and seasoned audio-video enthusiasts alike when you're faced with that array of input and output connectors. It helps to understand which connectors to use and what kind of signals each carries.

Banana Plugs: Use these instead of bare wire at the end of your speaker cables for convenient plug-in speaker (high-level) connections between your A/V receiver's speaker output terminals and your loudspeakers. No improvement in sound quality over bare wire. Virtually all 5-way binding posts on newer speakers and subwoofers accept either single or dual banana plugs, including all of Axiom's speakers. Many A/V receivers' speaker outputs also accept banana plugs if there is enough space. Note: Banana plugs won't work with older speakers' and receivers' plastic spring "push" connectors, which accept only bare wire.

A/V Surround Receiver: An audio/video component with a built-in radio tuner that will receive radio broadcasts on FM or AM, switch different audio and video input sources, and decode Dolby Digital or dts 5.1-channel soundtracks. A/V receivers also contain from five to seven internal amplifiers to amplify the audio signals for delivery to up to seven loudspeakers in a 7.1-channel home theater surround system. All A/V receivers also contain a separate Subwoofer output (the ".1" channel of 5.1 surround) to feed a powered subwoofer for deep bass effects.

Balanced (XLR or Cannon) Connector: A secure 3-wire connector found on all professional and semi-pro sound equipment and on some upscale consumer A/V components (including Axiom subwoofers), enabling very long cable runs without hum pickup or frequency response losses. Must be used with matching balanced connectors on an A/V processor, preamp, or A/V receiver.

Binding Posts, 5-way: A type of speaker cable input and receiver/amplifier output connector that accepts bare speaker wire when you unscrew the top and push the wire through the hole in the post, spade connectors, pins, and single or double banana plugs. Binding posts are only used for High-Level (also called Speaker-Level) connections for amplified audio signals from an A/V receiver's speaker outputs to the speakers.

Blu-ray: A new High Definition video disc standard developed by Sony and other partners that is not compatible with existing DVD players. A rival standard, HD-DVD, developed by Toshiba is currently engaged in a format "war" to decide which will become the High Definition video disc standard. Both are capable of delivering spectacular HD image quality on HD TV displays. Neither type of disc will play on a conventional DVD player, however, a Blu-ray or HD-DVD player will play conventional DVDs with the existing video quality.

Center Channel: In surround sound, a center-channel speaker placed above or below the TV screen, used to anchor the actor's dialogue and sounds occurring in the central part of the video image at the screen. The Center Channel is part of all Dolby Digital 5.1 and dts 5.1 surround formats.

CRT (cathode-ray tube): The familiar heavy glass "picture tube" common to TV displays for over 50 years but now becoming obsolete, replaced by LCD and plasma flat-panel displays as well as DLP and LCD rear-projection and front-projection display. Capable of superb color accuracy and picture detail viewable over a wide angle. Large, heavy, and limited to a maximum of 36 inches diagonal screen size.

Coaxial Cable: Standard 2-conductor shielded cable comprised of an outer woven metal shield (the ground connection) covered with plastic/nylon insulation and further insulated from the inner "hot" or positive wire. Used with RCA male plugs on each end for routing low-level analog audio signals from CD players, DVD players, cassette decks, set-top TV converter boxes, and satellite receivers to A/V receivers and amplifiers. The RCA plugs are often color-coded red for Right channel and white (or black) for Left. Also used for composite-video connection (color-coded yellow) and may be used for digital coaxial audio connection as well. Coaxial audio cable is also used between the A/V receiver's subwoofer output jack (color-coded purple) and the subwoofer line-in connection.

Component Video: Used for both Standard-quality video and High Definition video, it uses three coaxial cables with RCA male plugs color-coded red, green and blue (the three cables may be wrapped together for convenience) to carry analog Standard- or High-Definition video between a set-top satellite or cable-TV box to the A/V receiver and TV display or projector. Most new A/V receivers include component-video inputs and outputs that let you switch between different video sources. Note: Component video cables do NOT carry audio signals. You must connect separate audio cables (either analog or digital) to carry the sound portion of DVD and cable/satellite TV signals. Component-video connections deliver the best picture quality other than HDMI or DVI connectors.

Composite Video: A single video connector that combines all the color and brightness signals into one cable (hence "composite") using a single RCA male connector. Often color-coded yellow, it is the most common type of analog video connection between older VCRs and TVs (except for RF connectors). Use composite video only if your TV, VCR or DVD player lacks S-video or component-video connectors. Composite video will not carry High Def or progressive-scan video signals.

DLP (digital light processing): A TV projection technology developed by Texas Instruments that uses a light source (projector bulb) bounced off the surface of a tiny chip, a digital micro-mirror device (DMD) whose surface is covered by many thousands of tiny, moveable mirrors. Maintenance-free and capable of bright, high-contrast images with good blacks and rich color.

Dolby Digital 5.1 (DD 5.1): Developed by Dolby Labs, this digital surround format delivers up to 5.1 channels of sound. Used throughout the world as the standard soundtrack format for DVDs and High Definition TV as well as for the vast majority of movie soundtracks. All six channels are carried on one digital coaxial cable or optical digital link (Toslink) from the DVD player to the AV receiver. Dolby Digital may also be used for as few as 2 channels, in which case it's DD 2.0. Not all movies are mixed in 5.1 channels.

dts (Digital Theater Sound): A rival digital soundtrack format to Dolby Digital that is an option on some DVDs. Also used in many movie theaters. It is not a required standard for DVD soundtracks but may be included at the option of the producer. Virtually all DVD players and A/V receivers will decode dts or Dolby Digital soundtracks.

Dolby Pro Logic II (DPLII; DPLIIx): An enhanced version of the older Dolby Pro Logic surround system, this format will simulate 5.1-channel playback from a 2-channel stereo source of any kind. The most recent DPLIIx version simulates up to 6.1 or 7.1 channels if one or two back surround speakers are connected.

DVD-Audio: A high-resolution multichannel audio format that uses six or eight shielded RCA coaxial audio cables (sometimes bundled together) to carry analog surround-sound output from a DVD player capable of DVD-Audio playback. Many new A/V receivers have a six- or eight-channel Multichannel analog input set that accepts the multichannel analog audio output of DVD-Audio or SACD players. Don't confuse DVD-Audio with the usual Dolby Digital 5.1-channel or dts digital surround soundtrack of DVDs. DVD-Audio discs are playable only on Universal DVD players.

DVI (Digital Visual Interface): A large computer-like 18-pin connector that carries digital video signals, including High Definition signals, between a set-top HD cable or satellite box or DVD player and an HDTV set. DVI digital video signals are protected by HDCP (High-bandwidth Digital Content Protection) protocol, which prevents you from copying high-quality digital video. DVI is gradually being replaced by smaller HDMI connectors (see below). DVI/HDMI adaptors are available, and many HDTV displays and projectors have both types.

DVR (digital video recorder): An outboard video recorder often supplied by cable TV or satellite TV systems which uses a large-capacity hard drive to record and store video programs, either in Standard Definition or High Definition along with the digital audio surround soundtracks. Often integrated with the cable-TV HD tuner or satellite tuner.

Fiber-Optic (also called Toslink): A thin plastic or glass-fibre cable that carries digital audio signals in an optical format via pulses of light. Uses a small, square plastic male connector on each end. Most modern A/V receivers and DVD players have both Toslink optical digital as well as coaxial digital audio connectors. No difference in sound quality between optical or coaxial digital connections, but optical links are not susceptible to hum or interference.

HD-DVD: A new High Definition videodisc standard developed by Toshiba and other partners that is not compatible with existing DVD players. A rival standard, Blu-ray (see above) developed by Sony is currently engaged in a format "war" to decide which will become the High Definition video disc standard. Both are capable of delivering spectacular HD image quality on HDTV displays. Neither type of disc will play on a conventional DVD player, however, a Blu-ray or HD-DVD player will play conventional DVDs with the existing video quality.

HDMI (High-Definition Multimedia Interface): Much smaller and more convenient than DVI, HDMI is a USB-like digital video connector that carries the same digital video signals as DVI (High Definition and Standard Definition) but with the added advantage of conveying a Dolby Digital surround sound bitstream. Copy protected with HDCP so you can't pirate high-quality digital video. No image superiority of one over the other. May or may not produce a slightly better picture quality than component video.

HDTV (High-Definition TV): The new digital TV standard that features increased horizontal and vertical resolution, a choice of progressive or interlaced scanning, and a widescreen aspect ratio of 16:9 (the ratio of a screen image's width to its height) that conforms to the widescreen visual format of modern movies (older analog TVs have a squarish-looking 4:3 aspect ratio). The most common HD formats are either 720p (720 progressively scanned lines) or 1080i (1080 interlaced scanned lines) or some variation of these. DVDs, although digital, are Standard Definition (480i), which may be displayed as 480p. Some of the latest HD video displays are capable of 1080p clarity, a slight improvement over 720p or 1080i.

Interconnects: Any set of cables or connectors that link A/V equipment of all kinds, however, most commonly the term designates low-level RCA audio and video connectors rather than speaker cables.

Jack: Any female receptacle of an audio or video connector into which the plug, or male connector, is inserted. All connectors have male and female components, RCA plugs and jacks historically being the most common on consumer-grade audio/video equipment. Sometimes the terms jacks and plugs are used interchangeably.

LCD (liquid-crystal display): Color LCD panels used in flat-panel TV and computer displays, and in rear- and front-TV projection sets. Maintenance-free and capable of high resolution. Less than perfect blacks because in most displays light shines through the LCD panels to illuminate the image. May produce grid-like "screen-door effect" if pixels are too coarse, but great improvements have been seen in recent sets.

LCoS (liquid crystal on silicon): Similar technology to liquid-crystal display (LCD) but uses a light source reflected from the LCD panel rather than shining through it. Also known as D-ILA (direct-drive image light amplifier). Capable of performance comparable to DLP and LCD display.

Main Channels: In a 5.1-channel surround system, the front left, center, and right channel speakers. In a stereo system, the front left and right speakers.

Mini-jack, mini-plug: A miniature connector, in mono and stereo versions, commonly found on portable audio equipment for headphone and line-out connections. Rare on A/V gear except for "trigger" outputs and inputs that are used to remotely activate electric screens, separate power amplifiers and subwoofers in elaborate custom home theaters and installations.

Multichannel Analog Input: (see DVD-Audio, above). If your DVD player has the capability of playing back high-resolution DVD-Audio or SACDs, use this six-cable RCA connector set to connect to the analog multichannel input of the A/V receiver. Neither DVD-Audio or SACD hi-res discs have been proven popular.

Phono Jack: Always an RCA female connection on A/V receivers or preamplifiers for the output from a turntable's moving-magnet (MM) or moving-coil (MC) phono cartridge. Still available on up-market receivers and preamps. Don't confuse this with "Phone Plug" (or Jack), which is a larger and sturdier ¼-inch diameter connector used on consumer A/V equipment for larger headphones.

Plasma: A thin-panel video display that uses a huge array of tiny cells filled with ionized gas (plasma) which activates each cell's color phosphor. Viewable over a wide angle and capable of a brilliant image even in brightly lighted rooms. Has good contrast but tends to use more power than other types of video displays.

Receiver: An audio component with a built-in radio tuner that will receive radio broadcasts on FM or AM, switch different audio sources, as well as amplify the audio signals for delivery to loudspeakers. (see A/V Receiver above).

RCA Connector: By far the most common small audio or video connector used on consumer audio/video equipement, with a pin (male) plug and female jack. Uses 2-conductor shielded coaxial cable.

SACD (Super Audio Compact Disc; see DVD-Audio, above): a high-resolution digital multichannel audio standard developed by Sony/Philips that uses DSD (Direct Stream Digital) audio encoding. You'll need a bundled, shielded 6-cable RCA connector set to play back SACD to the A/V receiver as well as an SACD-compatible DVD player. Most inexpensive (less than $150) DVD players will not play SACD or DVD-Audio discs. Only "Universal" DVD players will play these formats as well as conventional DVDs and CDs.

SDTV: Standard-definition digital TV, defined as a 480i signal (480 interlaced scan lines) presented 30 times per second. This is the standard of resolution for all conventional DVDs. Many DVD players may be set to output "progressive scan" 480p signals, which remove the scanning lines producing a smoother film-like picture.

Speaker Cable: Available in various gauges or wire thickness, designated by "AWG" followed by a number e.g., AWG12 is 12-gauge speaker cable. The lower the number, the thicker the cable and the less resistance there is to the passage of amplified audio signals (AWG12 is thick; AWG18 is fairly thin) from you're A/V receiver or amplifier. All speaker cable is 99.9% oxygen-free copper. You'll need one 2-conductor cable for each speaker in your home theater system, except the subwoofer. A 5.1-channel system will require five separate speaker cables plus a single coaxial cable for the subwoofer (see Coaxial, above); a 7.1-channel system, seven cables plus a single coaxial sub cable. Choose the speaker cable gauge by the length of the cable run from the receiver/amplifier to the speaker. For runs up to 20 feet, 14-gauge is fine. Use 12-gauge speaker wire for long runs up to 60 feet. Good generic speaker cable can be purchased in bulk. Speaker cable does not impart musical qualities to the movement of electrons. All copper cables of sufficiently thick gauge sound identical.

Subwoofer: A speaker designed to reproduce only very deep bass frequencies from 100 Hz to 20 Hz or lower. Usually contains its own dedicated amplifier. It is the ".1" channel of Dolby Digital 5.1 and dts surround formats.

Surround Channels: A sound field that is 3-dimensional, intended to envelop the listener, rather than a stereo soundstage mainly in front of the listener. Normally achieve with two discrete surround speakers placed (ideally) to each side of the listening area, used to convey ambient sound effects, special effects and musical enhancement for Dolby Digital 5.1 and dts surround soundtracks. Many Dolby Digital and dts decoders in modern A/V receivers will extract and simulate two additional Back or Rear surround channels for 6.1-channel and 7.1-channel surround setups.

S-video: A small multi-pin connector cable that carries the chrominance (color) and luminance (brightness) video information separately. Not capable of carrying HD video signals but superior in picture clarity to composite video connections. Use this connector for better image quality if your TV, A/V receiver or VCR has S-video inputs and outputs.

Toslink (see fiber-optic, above): A plastic-fibre optical cable for carrying digital audio signals in optical form, as pulses of light, from a DVD player or CD player to an AV receiver. Will carry as many as six separate digital channels of audio for Dolby Digital 5.1 or dts surround soundtracks.

XLR (see Balanced Connector, above).

This list comprises the most common types of audio and video terms you are likely to encounter in setting up your speakers, A/V receiver, subwoofer, TV or HDTV, projector, DVD player, set-top cable box/satellite receiver, VCR or DVR and gaming console.

In this era of 5.1-channel to 7.1-channel surround sound, a receiver has to contain up to seven separate power amplifiers on one chassis, one for each of the five, six or seven discrete channels (most subwoofers have their own internal power amp). In the case of most A/V receivers, all of the internal amplifiers are powered by one transformer and power supply. To install five or seven amplifiers on one chassis, an engineer has to limit the receiver's maximum power output to 110 to 120 watts per channel in order to avoid problems of overheating or an unmanageably large and heavy chassis. And in many cases, the actual power output of an A/V receiver is measured with only one or two channels driven to maximum output while the other five channels coast along at one eighth of the rated output (so the advertised rating of most receivers doesn't give you the whole picture.)

Home theater enthusiasts in search of much higher real power output than A/V receivers offer, with big rooms and a taste for very high clean playback levels, and who have large speakers like the M80's that can handle many hundreds of watts per channel, will thus opt for a separate power amplifier of say, 250 watts per channel or more. It's the only way they can get enough real power to fill the big space with clean very loud sound. Since a separate power amp need only contain the amplification circuitry, it can be kept to a reasonable size, yet still have have generous heat sinks to cool the output transistors. Consequently, power amplifiers can typically drive lower impedances 4-ohm loads or lower with no danger of shutting down or overheating.

If you have a power amplifier, you still need a preamp or control section for source selection, surround decoding and processing, and level adjustment. That's where the A/V preamp-processor gets its name. Separate preamp-processors have lots of room inside for all sorts of extra inputs and outputs, so they are often more elaborate and versatile than A/V receivers. For instance, they might have phono inputs for both moving-magnet and moving-coil phono cartridges for vinyl playback or other features not commonly found on A/V receivers. And some preamp/processors will also have an onboard AM/FM tuner.

Specifications (distortion, noise, etc.) of preamp-processors and power amps are usually a bit superior to an A/V receiver, since there is better internal physical separation of wiring pathways (more room), hence less chance of interference (and resulting noise) from nearby hum-causing component parts. And having separates also means that you can upgrade to a larger or different power amplifier while keeping your preamp-processor.

Read the next tip: "Do I Need Two Subs?"

Do you have Axiom Speakers from the late 80s and early 90s? lf so, this section is for you! Click on the links below to see pictures from the early Axiom brochures for those speakers.

AX Towers - Award-Winning AX5 and AX3

AX Home Theater Speakers - The AX120 Subwoofer, AX1.2 Bookshelf Speaker, and the AX1.2 Center Channel as Part of the AX 1.2 Speaker System. Also the AX1 Speaker system, consisting of the AX500 Subwoofer, The AX1 Bookshelf, and the AX1 CenterChannel

The Award-winning AX1.5 Speaker family - the AX1.5, the AX1.5 Bookshelf, and the AX150 Subwoofer

The AX2 Speaker Family - AX2, AX2 Bookshelf, and AX 2+2

See the Awards these speakers won.

See the specs here.

Download a collection of brochures and awards sent in by a customer from British Columbia, Canada, here:

Vintage Collection 1

Vintage Collection 2

Home theater is this season's hottest trend! But what should you beware of when you purchase or upgrade a home theater? We've come up with a list of the Top Ten Mistakes people make when they buy home theaters. Remember, if you have any questions about a purchase when you've read the article, feel free to send me an e-mail.

1. Be cautious about those all-inclusive home-theater-in-a-box surround-sound systems from big brand name manufacturers noted for making great TV sets and audio/video receivers. That incredibly low price may be a false economy. If ________ (fill in Sony, Kenwood, any major electronics brand) knows how to build CD players, audio/video receivers, or TV monitors, they must know how to design and build excellent loudspeakers, right?

Wrong. Good speaker design is so specialized and requires such extensive acoustical research, measurement, and listening tests that the best speakers continue to come from companies like Axiom that specialize in the design and manufacture of loudspeakers.

2. Take your time, and listen to speakers using several of your favourite recordings. Experienced listeners and professionals will tell you that making careful judgments on different speakers takes many hours of listening, so don't be rushed. Use the same recordings of music you like for an objective comparison. If you have the option of auditioning the speakers in your own home, so much the better. That's the room where the speakers you buy will be placed, and there's no better place to listen to speakers than in the room you'll use them in.

3. Don’t be seduced by those little cube speakers because they're so tiny and unobtrusive. They may look cute and almost disappear into your room's decor, but those tiny satellite speakers can move only so much air. When things start to get loud with rock and roll or movies or big symphonic works, those little 2-inch cones inside get rattled and edgy.

Any speaker with a claim to high fidelity must divide the sound spectrum into two ranges, the bass/midrange for the woofer, and the treble for the tweeter. A single cone just can't do it well in normal rooms. As the price spectrum climbs, the best speakers divide the spectrum into three parts--bass, midrange, and treble--and use multiple drivers to achieve very clean high-quality sound.

4. Be realistic about the size of the room where you’ll use the speakers. Inexpensive small "bookshelf" speakers are great for rooms of modest dimensions. But if you get them for your 40- x 25-foot cathedral-ceiling living room, they’ll sound strained and edgy every time you turn up the volume.

A speaker is a kind of electrical air pump, and a modest single woofer and tweeter can't be expected to fill a huge room with wide-range sound at high listening levels. Bigger spaces require larger speakers.

5. Don’t expect compact speakers to produce deep, resonant thrilling bass. You can get pleasant usable bass to about 50 or 40 Hz from a compact bookshelf speaker, but if you want the deep and powerful sounds from a rock band or symphony orchestra, or the deep rumbling of a movie blockbuster, get a subwoofer to use alongside your compact speakers. Alternatively, get larger tower speakers.

6. Don’t be distracted by deep bass from a big subwoofer. (The subwoofer is a large black box dedicated to just deep powerful bass.) Instead, focus on whether the sounds from the main left and right stereo speakers and the center channel are smooth and clear without being harsh or strident.

Sure, deep bass from a subwoofer is desirable, but with movies or music, most of those upper bass, midrange and high-frequency sounds will come from the left and right front speakers and the center channel. Listen carefully to actors' and singer’s voices: Do they sound "boxy" or unnatural or hollow? Are "ssss" sounds at the beginning of words exaggerated (called sibilance), or sharp sounding? Do male actors sound nasal or if they had a head cold? Or are their voices "chesty" and too full? These are called speaker "colorations"--unnatural changes in the tonality of voices introduced by the loudspeaker, and they'll become tiresome and annoying after a short time.

7. Buy enough power—amplifier watts—to suit the size of your room, your listening tastes, and the demands of the speakers. Watts are comparatively inexpensive nowadays, but lots of receivers and amplifiers are still advertised using the misleading "total power output" ruse, which totals the individual power for all five channels. That "200-watt" receiver may have only 40 watts per channel (40 x 5 = 200), which would be adequate in a den or a dorm room but not enough for good home theater in an average-size living room.

Look for the receiver's power output stated per channel into 8 ohms at a specified distortion level, preferably with at least two channels driven. Receivers with power output of 70 to 100 watts per channel will be ample for all but the largest homes.

8. Be circumspect about speaker brand names that may sound sort of familiar, like "Sonic Research." Typically, such speaker manufacturers choose names with a slightly familiar ring, but the products are often disappointing. Some even have tweeters or woofers that aren't even connected. The best speakers come from dedicated speaker designers who have been in business for 20 years or more. It takes that long to refine and develop really great loudspeakers.

9. Don’t let your spouse or companion persuade you to hide your new speakers inside an antique armoire or entertainment unit. Why buy really good speakers if you're going to place them inside shelving units or armoires? It's the old law of boundary effects. The more surfaces near a speaker, the greater the likelihood of unpleasant sound colorations occurring. A speaker needs to operate more or less in free space. Smaller speakers sound their best on stands. Leave the armoire for electronics and storing CDs!

10. Check out detailed speaker test reports and reviews in reputable audio/video magazines and on Internet forums. Read message boards for owner's comments on particular brands and models of speakers. Ask questions about the quality and type of the individual component parts. And don't fall for the slick ads for package systems from famous-name manufacturers that spend millions on promotion and little on research and design. Sad to say, some companies use the cheapest possible cone drivers, diverting most of their profits not to research and development of better sounding speakers, but to getting manufacturing costs to basement levels. The systems ultimately disappoint; indeed, in some cases the basic design hasn't changed in 30 or 40 years. But the ads are very compelling.

How would you like to feel immersed in the soundfield of the movie you're watching, similar to what you experience in a large Dolby Digital or THX commercial movie theater—only you'd be in your living-room, den, or family room? The sound of arrows whizzing over your head in Gladiator, or helicopters flying to your left and right in Black Hawk Down? Virtually every major movie release on DVD nowadays has a Dolby Digital 5.1-channel soundtrack. That's six separate and distinct channels: left and right front; a center channel for movie dialogue; two surround channels for directional and ambient sound effects; and a sixth ".1" low-frequency effects (LFE) channel that feeds your subwoofer to recreate the movie-theater impact of those dinosaur footfalls.

All this is possible with Axiom's QS Quadpolar multi-directional surround speakers. And it's remarkably affordable. If you're presently using conventional forward-firing speakers in at the sides or rear of your room, or even if you haven't yet installed a home theater system, consider acquiring a pair of Axiom QS4 or QS8 surround sound speakers.

Unlike conventional surround speakers that use only a single woofer and tweeter firing out towards the listener, Axiom's five-sided QS multipolar surrounds each use four drivers, a tweeter on each angled baffle, and a woofer/midrange driver on the tope and bottom of the enclosure.

"But mamma! The QS8s are astonishing. Period. No qualifiers are needed — not for the money or of their type or considering. I have simply never had a surround speaker that better lived up to the surround paradigm. In fact, the QS8s did such a full-bodied, completely immersive job of distributing Black Hawk Down's soundscape all around me, that I spent a certain portion of the movie keeping my head down in response to the metal I heard flying around." - Wes Phillips, onhometheater.com

But the QS surrounds do all that even in rooms as small as a modest den. And the QS surrounds are supplied with wall-mounting brackets so you can attach them out of the way two or three feet above ear level to either side of the listening/viewing area.

Axiom QS surrounds come in two sizes, for small to medium and large rooms. Think of a medium-sized or typical living room as having about 2,200 or 2,500 cubic feet, or measuring about 18 x 14 feet with 9-foot ceilings. Axiom's QS4 Quadpolar surround speakers would be ideal for this room. The QS4 uses two 1-inch titanium-dome tweeters for high frequencies and dual 4.5-inch aluminum-cone woofer/midranges in a sealed enclosure available in Boston cherry, black oak, or maple finishes. The cost? Just €471.00 EUR per pair, including all taxes, duties, and two-day FedEx air shipment anywhere in North America.

The QS8 surround speakers are best for large or medium-to-large rooms, those with over 2,500 cubic feet. The QS8s have dual 1-inch titanium dome tweeters and twin 5.25-inch aluminum-cone woofers. The 1-inch tweeters also use 1-inch voice coils for high power-handling and extra-clean sound at realistic levels.

Axiom's QS8 Quadpolar surrounds are priced at €604.00 EUR /pair . All the Axiom QS surrounds include all taxes, duties, two-day FedEx air shipment, a 5-year warranty, and the 30-day in-home money-back (less return shipping) trial if you're unsatisfied with Axiom's enveloping sound quality.

If you need advice on which pair of Axiom Quadpolar surround speakers would best suit your room, please don’t hesitate to call our toll-free number – 1-888-352-9466 – between 9:00 am and 11:00 pm Eastern, to get free, friendly advice from our Audio Experts.

The receiver serves as the control unit, switching and amplification center for your entire system (it's a "receiver" because it contains a built-in AM/FM radio tuner). If it lacks an AM/FM tuner, it would be an "integrated amplifier," or just plain "amp," for short. The receiver and its remote control let you select which source to listen to (CD player, FM tuner, tape deck, VCR, or DVD player) or watch (if it's an audio-video receiver). When you press "CD" on the remote, the receiver internally switches its amplifiers to the incoming signal from your CD player, passes those signals through its control section (tone, balance and volume controls), then to its built-in amplifiers and sends the greatly strengthened audio signals to your speakers (and the accompanying video signal to your TV, if you selected "DVD" or "VCR" on an A/V receiver).

First, however, you must choose whether to get a simple stereo receiver that has two internal amplifiers to drive a pair of speakers, or instead, an A/V surround-sound unit that will have a minimum of five internal amplifiers to drive five speakers in your room: the left and right main speakers up front, a center-channel speaker atop your TV, and two surround speakers on the side walls. The sixth or ".1" channel, as in "5.1," is for just deep bass and low-frequency soundtrack effects. That Low-Frequency Effects (LFE) ".1" channel is sent to your subwoofer, which almost always has its own internal amplifier. Surround-sound A/V receivers also have internal digital decoders to sort out the DVD player's Dolby Digital or dts digital 5.1-channel soundtrack.

In recent years, 5.1-surround sound has evolved to 7.1 surround speakers, adding an extra two surrounds to really complete the effect of envelopment.

By comparison, stereo receivers are blessedly simple-just two internal amplifiers, no surround sound circuitry, and two pairs of speaker output connectors for the left and right channels. That still appeals to some buyers. However, prices of surround-sound 7.1-channel A/V receivers have become so competitive that they cost little more than a basic 2-channel stereo model. So consider very carefully whether or not you're planning a home theater system for a future (or bigger) home or if you want plain old vanilla stereo. Moreover, if you think that at some point in the future, you might be persuaded by the sheer pleasure of surround sound then now is the time to go for a multi-channel A/V receiver. Any A/V receiver is usable in a pure stereo form if you wish, with or without an accessory subwoofer. In most units, you simply hit a button on the remote labeled "Surround Off" to switch back to a stereo 2-channel mode.

The rated power output of the receiver's internal amplifiers, stated in watts per channel into 8 ohms, will ultimately determine the unit's selling price. The more power you buy, the more costly the receiver. But "solid-state" (transistor) amplifiers are very economical. You can find stereo receivers with 80 or 100 watts or more per channel for as little as $300. A/V surround receivers with similar power also start at this price level. Don't scrimp on the power: the greatest source of damage to speakers is using too small amplifiers to drive speakers at high volumes, especially when you might "crank it up" at a party. The amp runs out of watts, distorts, and the distorted signal burns out tweeters or woofers in seconds. And one basic truth most consumers do not understand when they are shopping for amps and speakers: smaller speakers generally require more power-not less-to produce realistic volume levels than big speakers do because they use smaller woofers and are less efficient.

In all but very large living rooms or those with cathedral ceilings and volumes of 6,000 to 7,500 cubic feet, receivers with 80 to 100 watts output per channel to all five channels will be sufficient for most listeners who like fairly loud music with movie soundtracks or CDs. Listeners used to insanely loud volume levels with large floorstanding speakers should look at separate power amplifiers with 200 to 350 watts per channel. Modest little 35-watt amplifiers may be OK for a den or a dorm but they just can't cut it in an average living room unless you're going to listen at background levels. And background levels are strictly low fidelity - we don't go to a concert and tell the musicians, "Hey, play really quietly!"

Now you know what it is . . . so what do you need? Click here to send an email directly to Alan Lofft for an expert recommendation based on your room size and listening preferences, or contact us toll-free at 1-888-352-9466 for fast, free, friendly advice.

In real life, our ears and brain interpret sounds from every direction, in a 360-degree circle, including even the dimension of height. Like a super computer running in high gear, our sophisticated hearing system decodes spatial and directional information in real time, telling us instantly the tonality, frequency content, and loudness of sounds from all directions.

Simple stereo, on the other hand, uses just two speakers at the front left and right, to try and simulate the complex directional and spatial information that we hear in real life. It does a decent job of reproducing a musical event, even fairly impressive at times. But it is limited to those two boxes up front, and two directions, give or take a bit. Even as early as the 1930s, Bell Telephone scientists concluded that a minimum of three channels were necessary to convey a reasonable simulation of an orchestral performance—two channels at the left and right, and one in the middle.

In the late 1950s and '60s, Hollywood sound engineers realized that more channels of sound were better, and added magnetic stripes to the edge of epic 70mm widescreen movies, which delivered up to six separate "tracks" or sound channels. Audiences loved the effect: Multiple channels more closely approximated the multidirectional sounds our ears pick up in everyday life. There was a center channel behind the screen for the actor's dialogue; left and right front speakers for the music, and eventually, left and right surround speakers on each side of the movie theater for ambient sounds-the wind in the trees, crickets in summer, and the howling of wolves. Yikes!

But back then, home audio technology wasn't up to the task of duplicating these events in our living room. Now it is, and it's called "Home Theater"! First came Dolby Surround, with four channels, in the 1980s, and now we have Dolby Digital 5.1-channel sound on virtually every movie issued on DVD. That's six separate or "discrete" channels of sound: left and right front main channels (like stereo), a dedicated center channel speaker for dialogue to anchor the actor's voices at the TV screen no matter where you're sitting, two left and right surround speakers at the sides of your listening area for all those ambient environment sounds, and a sixth deep bass subwoofer channel—it's the ".1" in 5.1—which contributes the shakes and shudders of thunder, explosions, and powerful musical bass effects. If you've kept count, that's a total of five "satellite" speakers—plus one subwoofer for ultra-low bass. Now you see why we need six speakers. And those engineers are working on one more, for height!

Now you know what it is . . . so what do you need? Click here to send an email to our audio experts for a recommendation based on your room size and listening preferences, or contact us toll-free at 1-888-352-9466 for fast, free, friendly advice. 

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Home Theater Basics: Buying A DVD Player
Home Theater Basics: Home Theater Components

A is for Area

Other things being equal (and there are many trade-offs that a designer may consider), the larger the woofer or woofers' cones' area and the larger the enclosure (those two have to be combined) the greater the potential for more output and deeper bass. (That's why very small speakers need subwoofer assistance to reproduce convincing powerful bass.)

B is for Box

EP500 Powered subwoofer in Cherry Wood, Chestnut Stain, Satin Finish.

It's possible to get deep bass from a small subwoofer enclosure, but the designer usually sacrifices efficiency and maximum loudness capability. The smaller sub with its typically smaller driver has to "work" harder to excavate frequencies, so it will also need a powerful amplifier, and because the small driver moves in and out over a greater distance (excursion) to generate the pressure waves, it won't play as loud as a sub that uses a big box and larger-diameter driver. For example, Axiom's EP400 sub uses a compact cabinet with a smaller 8-inch dual-voice-coil driver powered by a 500-watt amplifier to produce ultra-low frequencies to 20 Hz. But it's better suited to smaller rooms and it won't play as loud in big rooms as its bigger EP500 brother, with its 12-inch diameter driver and larger cabinet.

C is for Corner

Corner locations of subwoofers and floorstanding speakers will produce powerful bass but often it isn't all that smooth. One or two notes may stand out, sounding bloated, like the old days of pounding disco "one-note" bass. A better location is part way along a side or rear wall. As you move a subwoofer away from a corner, deep bass becomes more even with less of a tendency to get "boomy".

D is for Class D

Almost all subwoofer amplifiers nowadays are class D switching designs because they run cooler, are more efficient and use less power, and are typically lighter and physically smaller than older analog amps.

E is for Enemy

EP800 Powered subwoofer in Rosewood, Natural Stain, High Gloss Finish.

The enemy of powerful deep bass is poor placement of the subwoofer and/or your listening seat. Don't put your couch in the center of a room because often that is where there's a "null" or cancellation of bass. Sitting about 60% to 80% back from the front wall is about right. Avoid placing the couch against a rear wall. Typically that produces unnatural bass boost, a sort of hot spot like a corner location.

F is for Frequency

If you don't like the quality or quantity of bass you are getting, then move the subwoofer to a different location. Swap places with the subwoofer and your listening area, putting the sub where you normally sit. Crawl around the room while playing music with deep bass and the spot where the bass is smoothest and best is where you should move the subwoofer. And speaking of frequency, more subwoofers are always better than a single one. The goal is to get deep, smooth and even bass at all listening locations and there is no better means to that end than adding a second subwoofer. Placing a second sub at opposite ends or opposite sides of the room will result in much smoother and better bass for all viewers and listening location

In the process of finding the amplifiers, loudspeakers, and subwoofers to bring the pleasures of high fidelity music into our homes, we encounter lists of technical specifications that include distortion measurements. Distortion is considered to be any unwanted noise or deformation of the audio signal that the device amplifying and reproducing the music might cause. The culprits include any equipment in the reproduction chain through which the audio signal passes on its way to becoming sound in your living room and reaching your ears. Working backwards, this includes loudspeakers and subwoofers, amplifiers (transistor or tube), mastering recorders, preamplifiers, digital signal processing (DSP) chips, analog and digital recorders, mixing boards, and microphones. It's a large subject, but for these tests we focused on potential loudspeaker and subwoofer distortions and their audibility with music playback, using pure tones as a noise test signal.

Lists and technical numbers purporting to describe distortion that a device introduces—like the commonly stated percentage of Total Harmonic Distortion plus Noise (0.03% THD + N) seem fairly abstract on the page. We can scan the percentages or look at the graphs of relative distortion versus an amplifier or loudspeaker's output at various listening levels, but it's hard to imagine what those figures represent under real-world listening conditions. Will we hear it with music? How much distortion can we tolerate or even detect? Are there some types of distortion that are more audible than others? How much distortion does it take (and at what frequencies) before it intrudes and spoils the listening experience? Are there benefits or penalties to reducing distortion levels that are already inaudible? For example, in the 1970s, one of the unintended consequences of the rush to reduce distortion in early solid-state amplifiers by adding large amounts of negative feedback to the circuit (doing this reduced amplifier distortion levels to vanishingly low numbers like 0.001% THD) resulted in a type of distortion called Transient Intermodulation Distortion (TIM), first uncovered by Finnish researcher Matti Otala. On sudden musical transients in a solid-state amplifier using large amounts of negative feedback, TIM could excite the amplifier into oscillation, resulting in an audible and nasty high-frequency distortion. Consequently it's worthwhile viewing distortion numbers with caution when making a purchasing decision. Ever-lower distortion numbers may not contribute to improved sound quality.

Debbie Swinton, analyzing the audio configurations
during one of our listening sessions.

In real-life situations, we're all too familiar with distortion as extraneous, unwanted noise a cell phone ringing or people coughing during a concert, for example or the background rumble of air-conditioning or air-circulation equipment in an auditorium during quiet passages of a recital.

The history of recorded and reproduced sound has always been towards improving recording and playback equipment to reduce distortion and get rid of extraneous noise and artifacts that distract us from musical enjoyment. So any noise that isn't part of the original music signal must be viewed as a distortion, including that added by the analog recording medium. The LP era had its groove swish plus the irritating pops and clicks of vinyl-pressing imperfections and accumulated dust. Even the original master tapes fed to record-cutting lathes contained high-frequency hiss, the latter still audible on many CD reissues of early tape masters that haven't been processed through noise-reduction devices (in removing the noise, these devices may introduce other audible artifacts that may degrade the signal!). Looking back, many of us played and enjoyed vinyl discs for decades because it was the only practical, decent-sounding and inexpensive recording and playback medium available. However, in retrospect, it's amazing how much noise and distortion we tolerated along with our music.

For all but a few, the introduction of digital recording and playback systems banished the most annoying distortions of analog disc recording and playback groove noise, tape hiss, ticks and pops, slow and fast speed irregularities (wow and flutter, respectively), turntable rumble, tracking distortion and the sometimes severe dynamic limitations of phono cartridge playback. The latter imposed a type of dynamic compression when things got too loud and/or contained too much bass for the grooves of a vinyl disc to contain. (Except for a few direct-to-disc recordings, virtually everything recorded onto vinyl was processed through a dynamic limiter or compressor, otherwise no phono cartridge would play the grooves.)

Loudspeakers and subwoofers are analog devices, but the last three decades of loudspeaker design have seen gradual improvements in reducing potential distortion. Still, the lingering question remains: when does distortion become audibly significant?

This is what Axiom set out to determine, and to do so in a controlled experimental environment using blind and non-blind listening tests with a group of listeners ranging in age from 22 to 60. These tests were a more formal, scientifically controlled version of tests Axiom did on the same subject decades ago.

Masking Effects

Anecdotal reports and conventional wisdom have suggested that distortion may become a serious problem at levels below 1%. Indeed, some reviewers and listeners have claimed to detect audible glitches at a fraction of this value. While previous researchers using sine-wave test signals and headphone playback have reported thresholds of detection well below the 1% level, research using actual program material music and loudspeaker playback indicate that the masking effects of music may conceal audible distortion until it increases to levels well above the 1% level and our ears begin to detect its presence. The effects of perceptual masking of other musical frequencies have been well documented: When a quiet musical sound a harp, for example-- is close in frequency to a louder musical signal a trombone section, say then we simply don't hear the harp because the trombones' powerful sound masks the delicate tones of the harp. This phenomenon forms the basis of  perceptual coding systems like Dolby Digital, dts, MP3, Windows Media and other data-reduction schemes, which dramatically reduce the amount of data storage required for complex music signals and multi-channel soundtracks on DVDs and other digital media. Such data-reduction schemes or algorithms are called lossy because large amounts of data are discarded, which frees up additional space for audio and video storage on the disc. Other recording systems such as CD, SACD, and DVD-Audio are lossless because no data are discarded.

Distortion and the masking effects of music are especially important with loudspeaker and subwoofer playback, since these two devices are the actual producers of sound in the listening room. And because they use reciprocating motor assemblies, the mechanical excursion of voice coils, diaphragms, cones and domes makes them more susceptible to unwanted movement and other distortions in their mission of pressurizing and moving air molecules to create audible sound waves.

The Test Procedure

Two selections of rock/pop music of limited dynamic range typical of modern-day rock recordings were selected from Phil Collins's Hits and Barenaked Ladies' Gordon albums. The limited dynamic range of +/- 5 dB allowed us to introduce the noise without having to follow the music level up and down throughout the song. The musical selections on CD were played in stereo on a pair of wide-range loudspeakers (Axiom M80ti's) operating with an Axiom EP600 subwoofer. Pure sine-wave tones at fixed frequencies were played over a third M80 speaker and EP600 subwoofer (all speakers and subwoofers were concealed behind an acoustically transparent but visually opaque curtain), at gradually increasing loudness levels until the listener detected their presence and signaled by a raised hand that something in the music doesn't seem right. Bryston and Yamaha Pro amplifiers were used in the playback chain.

The first group of eight listeners (average 92 dB SPL playback level) ranged in age from 20 to 60 (+/-3 dB) and included a mix of male and female auditioners chosen from Axiom staff as well as a few guests who happened to be visiting the Axiom plant in Northern Ontario. All reported normal hearing acuity. Each listener participated in individual listening sessions that typically lasted about 20 to 25 minutes. The tests were then repeated with an additional eight listeners at an average level of 89 dB SPL, and a further group of eight was tested at 86 dB SPL. Interestingly, the results demonstrated that the average amplitude level of the music playback did not affect the noise detection results. At each test level, the ability of listeners to detect the noise distortion depended on the relative loudness of the noise signal to the music, not on the overall average loudness of the music.

The noise or distortion test signal consisted of pure tones at fixed frequencies of 20 Hz, 40 Hz, 80, 120, 160, 200, 240 Hz and so on up to a high-frequency limit of 10 kHz. The test signals were chosen to simulate what loudspeakers would do under normal operating conditions. The pure tones were played over the third loudspeaker and subwoofer at gradually increasing levels of loudness along with the music from the stereo speakers and subwoofer. The test tone would be left on for two or three seconds, then off for a similar period of time, the test tone gradually increasing in loudness until the listener detected the noise, signaled by raising his or her hand. The tone would then be reduced in level until the listener lowered his or her hand indicating that the tone couldn't be heard anymore. This would be repeated to verify the noise level at which the listener detected the distortion. Data were recorded for each listener and each test frequency for both of the musical selections and plotted on a graph. Figure 1 shows the final average result for all 24 listeners.

Initially, individual listeners were told to raise their hand only if they heard something in the music that doesn't seem right. As the tests proceeded, alternate listeners were told the exact nature of the teststhat we were going to introduce a series of pure tones along with the music at increasingly louder levels. We also specified the exact frequencies and the order of the noise signals, i.e., 20 Hz, 40 Hz, and so on. Amazingly, the results were the same whether the listeners were told the test procedure in advance or not. Tests were then repeated beginning at 10 kHz, moving down in frequency to a lower limit of 20 Hz. Again, the results were the same whether we started at the top and moved down, or began at 20 Hz and moved up to 10 kHz.

Figure 1, Distortion Detection vs Frequency

The tests were repeated with music at average listening levels of 86 dB SPL, 89 and 92 dB, measured at the listening seat with a professionally calibrated Sound Pressure Meter. Subjectively, these levels ranged from normal to quite loud. All the listeners were comfortable with these playback levels. In the graph in Figure 1, the horizontal line at 0 dB represents the average level of the music. Typical dynamic range between +5 and -5 dB could be measured during playback of the musical selections. The small squares on each curve represent the specific frequency points of the sine-wave distortion fed into the listening room along with the music. As can be seen in Figure 2, the results with the different musical selections track each other very closely, indicating that the nature of the particular music did not significantly change the results.

Figure 2, Results with Different Source Material

Figure 1 shows the combined average of all results together with a sloping trend line representing the test subjects' average ability to detect the distortion at lower levels as the frequency increases. The graph in Figure 3 documents the individual detection curves for each of the eight listeners at the 92-dB average listening level. The congruity is remarkable. Only one obvious deviation at 10 kHz, for the oldest listener in the tests, shows any significant departure away from the other listeners' curves. Even at much higher frequencies, 5 kHz for example, the distortion tone had to be raised to an average of just 30 dB below the music level (about 3% distortion) before listeners could hear it along with the music.

Figure 3, Distortion Detection vs Frequency @ 92 dB

The Results

While it is has been recognized for years that human hearing is not very sensitive to low bass frequencies, which must be reproduced with much more power and intensity in order to be heard, what these results show is that our detection threshold for noise (made up of harmonically related and non-harmonically related test tones) is practically non-existent at low frequencies. (The noise test tones are noise in the sense that they are not musically related to tones commonly found in musical instruments.) In fact, the noise tones at 20 Hz and 40 Hz had to be increased to levels louder than the music itself before we even noticed them. Put another way, our ability to hear the test frequency noise tones at frequencies of 40 Hz and below is extremely crude. Indeed, the results show we are virtually deaf to these distortions at those frequencies. Even in the mid-bass at 280 Hz and lower, the noise can be around -14 dB (20% distortion), about half as loud as the music itself, before we hear it.

Conclusion

Axiom's tests of a wide range of male and female listeners of various ages with normal hearing showed that low-frequency distortion from a subwoofer or wide-range speaker with music signals is undetectable until it reaches gross levels approaching or exceeding the music playback levels. Only in the midrange does our hearing threshold for distortion detection become more acute. For detecting distortion at levels of less than 10%, the test frequencies had to be greater than 500 Hz. At 40 Hz, listeners accepted 100% distortion before they complained. The noise test tones had to reach 8,000 Hz and above before 1% distortion became audible, such is the masking effect of music. Anecdotal reports of listeners' ability to hear low frequency distortion with music programming are unsupported by the Axiom tests, at least until the distortion meets or exceeds the actual music playback level. These results indicate that the where of distortionat what frequency it occurs is at least as important as the how much or overall level of distortion. For the designer, this presents an interesting paradox to beware of: Audible distortion may increase if distortion is lowered at the price of raising its occurrence frequency.

Next episode: The effects of harmonic distortion

The tests done in this experiment are essentially noise tests; things such as mechanical resonances and port noises that are not harmonically related to a specific fundamental contained in the music would be examples of noise distortion. Other types of distortion such as Harmonic Distortion and Intermodulation Distortion have a direct relationship to a frequency being reproduced as part of the music. These types of distortion may be harder to detect than straight noise distortion; a subject for a future round of experiments.

Since 1982, Axiom has been an integral part of the research into psycho-acoustics and the relationship between loudspeaker anechoic measurements and real-world listening tests. Read more about the research here.

In order to facilitate the higher volume of ongoing research and development at Axiom, we are installing our own anechoic chamber, identical to the chamber located at the National Research Council in Ottawa, pictured left.

Above, the 'floating floor' is installed. The entire chamber is elevated on springs to completely isolate it from floor-conducted vibration.

Next, the walls are erected. After the walls, the ceiling goes on.

The outside structure is complete.

Work begins on installing the sound-absorbing wedges on all six interior surfaces of the chamber.

Once all the wedges are installed, the chamber will be tuned to match the reference anechoic chamber at the NRC (upper left), and then a pivoting, rotating speaker holder will be added.

Finally, a lab with measuring and calibration equipment will be added to the front of the chamber. For more photos of the construction of the Axiom Anechoic Chamber, click here.

Tom Cumberland

Debbie Swinton

Related Links:
The National Research Council (NRC)
Anechoic Chamber (Wikipedia)

Clearly, such social isolation won't endear you to family and friends, so compromise is in order. And given the understanding that no room is ideal (not even a room with asymmetrical dimensions), the trick is to combine careful subwoofer and furniture placement (with the possibility of using two subwoofers) to more evenly distribute the deep bass frequencies throughout the room. Then every listener will hear the powerful bass frequencies that bring impact to home theater and music.

As you might suppose, a subwoofer and your particular room work together. It's not just the location of the subwoofer that matters: where you place the sofa and chairs is just as important. What follows are some subwoofer room-placement basics:

• The worst place for a subwoofer is in the middle of a room.
• The most difficult room shape is square, so if you have the flexibility to choose which room you'll use for home theater or you are building a new home and designating a space for home theater, avoid rooms with equal dimensions.
• As you move the subwoofer closer to a wall, the bass output will become stronger.
• Bass output will be maximized as you push the subwoofer into a corner.
• The closer you sit to a wall, the more pressure your ear will pick up and the greater the bass intensity will be, but it may become uneven— alternately boomy or anemic as you move in either direction.
• Adjusting the distance of the couch or chairs relative to the walls and/or the subwoofer relative to the corner will almost always be beneficial in helping smooth out the deep bass heard at several listening locations in the room.
• Adding a second subwoofer won't cure the problem of standing waves or uneven bass, but it will result in a greater number of listeners hearing smoother overall bass in more locations. Try placing the second subwoofer in a location near the wall opposite the first subwoofer.  Learn more about using two subwoofers here.
• Avoid rooms with concrete floors and walls. Walls where the wallboard flexes are more absorptive and produce fewer problems with "bass boom." If you can' t avoid concrete walls, add studs and one layer of wallboard to the walls of the room to further aid absorption.

The advice I supplied in a newsletter some time ago, now in the AudioFile archives is worth repeating:

Move your subwoofer as close as you can to where you sit. If it's a chair, move the chair aside and place the sub in the spot where the chair was. If it's a couch, slide the couch temporarily out of the way and put the sub about where you usually sit.

Play a DVD with lots of low-frequency effects or a CD with plenty of deep bass, the kind that really kicks your sub into serious bass output. Get out the kneepads and crawl about the room in the general area where you were thinking of locating the sub.

Go several yards in each direction—near the wall, out from the wall, towards a corner, away from the corner, and so on—while you listen for smooth and extended deep bass response, free of exaggeration and "one-note" boom. Mark the spot, then move the subwoofer into that position. Now put the furniture back. If you are using two subwoofers, mark two locations and place the subs in those two positions.

The Tech Talk

All subwoofers produce acoustical pressure, and that is what your ear responds to. The only place where you will hear the bass output that your subwoofer produces exclusively is out of doors (or in an anechoic chamber). But soon as you put a subwoofer into a room, the sound waves bounce back and forth between the parallel surfaces of the room, some combining or "adding," which will emphasize those sounds, and others canceling each other out, which results in a null. If you are sitting in a null, you won't hear any deep bass at all. Conversely, if your chair is in a location where standing waves peak, you will likely hear boomy, one-note bass (you won't be able to follow the tuneful bass line of a recording, for example). Sometimes, by just moving a foot or two, the deep bass will "magically" reappear.

Quick Tips:

• Two Subwoofers: Better Bass for More People
• Subwoofer Placement Tips
• Subwoofer Level Adjustments

What follows is an alphabetical list of the most common types of connectors used between your new A/V receiver, video display (with an emphasis on HDTV), DVD/CD player, loudspeakers, and subwoofer, with some explanatory tips and helpful info on getting your system up and running. (See the A/V Tip, above, on kick-starting your subwoofer if no deep bass is forthcoming when you crank up "War of the Worlds.")

Banana Plugs: Use these only for speaker (high-level) connections instead of bare wire between your A/V receiver's speaker output terminals and your loudspeaker input connections. Convenient for quick connection or disconnection of speaker cables. No improvement in sound quality over bare wire or spades, but less likely to short circuit or corrode, especially if gold-plated, than bare cable. Virtually all 5-way binding posts on newer speakers and subwoofers accept either single or dual banana plugs, including all of Axiom's speakers. Many A/V receivers' speaker outputs also accept banana plugs if there is enough space. Note: Banana plugs won't work with older speakers' and receivers' plastic "push" connectors, which only accept bare wire.

Balanced (XLR or Cannon) Connector: A secure 3-wire connector found on all professional and semi-pro sound equipment and on some upscale consumer A/V components (including Axiom subwoofers), enabling very long cable runs without hum pickup or frequency response losses. Must be used with matching balanced connectors on an A/V processor, preamp, or A/V receiver to benefit from its hum-free traits. Over long cable runs, sound quality will be better than that of conventional shielded RCA coaxial cables because increased cable capacitance in the latter may induce losses in frequency response.

Binding Posts, 5-way: A type of speaker cable input and receiver/amplifier output connector that accepts bare speaker wire when you unscrew the top and push the wire through the hole in the post, spade connectors, pins, and single or double banana plugs. Binding posts are only used for High-Level (also called Speaker-Level) connections for amplified audio signals from an A/V receiver's speaker outputs to the speakers. Stereo systems with amplifiers or preamps lacking a subwoofer output would also use the amplifier's high-level outputs and the subwoofers hi-level inputs. Signals may be routed through the subwoofer and then to the main speakers, or separately from the amplifier to the main speakers with a second set to the subwoofer. The receiver/processor's internal bass management cannot be used with high-level speaker/subwoofer hookups.

Coaxial Cable: Standard 2-conductor shielded cable comprised of an outer woven metal shield (the ground connection) covered with plastic/nylon insulation and further insulated from the inner "hot" or positive wire. Used universally with RCA male plugs on each end for routing "low-level" (also called line-level) left and right analog audio signals from CD players, DVD players, cassette decks, set-top boxes, and satellite receivers to A/V receivers and amplifiers. The RCA plugs are often color-coded red for Right channel and white (or black) for Left. Also used for composite-video connection (color-coded yellow) and digital coaxial audio connection as well as analog SACD or DVD-Audio analog multichannel outputs and inputs. Coaxial cable is also used between the A/V receiver's subwoofer output jack (color-coded purple) and the subwoofer line-in connection.

Component Video: The most common type of connector used for both Standard-quality video and HD video, it uses three coaxial RCA cables and plugs color-coded red, green and blue (the three cables may be wrapped together for convenience) to carry analog Standard- or High-Definition video between a set-top satellite or cable-TV box to the A/V receiver and TV display or projector. Most new A/V receivers include component-video inputs and outputs that let you switch between different video sources. Note: Component video cables do NOT carry audio signals. You must connect separate audio cables (either analog or digital) to carry the sound portion of DVD and cable/satellite TV signals. Component video cables keep the color elements of a video signal separate from each other and should always be used between matching video devices that have component video inputs and outputs.

Composite Video: A single video connector that combines all the color, brightness, and sync signals into one cable (hence "composite") using a single RCA connector. Often color-coded yellow, it is the most common type of analog video connection between older VCRs and TVs (except for RF connectors). Use composite video only if your TV, VCR or DVD player lacks S-video or component-video connectors. Composite video will not carry High Def or progressive-scan video signals.

D-Sub: A type of multipin connector so-named because of its rough "D" shape, originally used in computer and data applications and now used in several variants for audio/video purposes. See VGA and RGB.

DVD-Audio: A high-resolution multichannel audio format that uses up to eight shielded RCA cables (sometimes bundled together) to carry analog surround-sound output from a DVD player capable of DVD-Audio playback. Many new A/V receivers have a six- or eight-channel Multichannel analog input set that accepts the multichannel analog audio output of DVD-Audio or SACD players. This connection may also carry decoded Dolby Digital 5.1 or dts signals but most DVD soundtracks, whether Dolby Digital or dts, are normally conveyed with a single digital audio cable, either optically (Toslink) or coaxially, to the digital audio input of the A/V receiver. Don't confuse DVD-Audio with the usual Dolby Digital 5.1-channel or dts surround soundtrack of DVDs. Most inexpensive (less than $150) DVD players will not play high-resolution DVD-Audio or SACD formats. "Universal" DVD players will play these formats as well as conventional DVDs and CDs.

DVI (Digital Visual Interface): A large computer-like 18-pin connector that carries digital video signals, including High Definition signals, between a set-top HD cable or satellite box or DVD player and an HDTV set. DVI digital video signals are protected by HDCP (High-bandwidth Digital Content Protection) protocol, which prevents you from copying high-quality digital video. DVI is gradually being replaced by the smaller HDMI connector (see below). DVI/HDMI adaptors are available, and many HDTV displays and projectors have both connectors. Although a DVI or HDMI connection eliminates several digital-to-analog and A/D conversions, it does not visibly improve image quality over correct component-video connections and may introduce incompatibilities in the HDCP anti-copy protocol (see HDMI). Component-video can, with proper signal levels, give exactly the same quality as HDMI or DVI as long as the native resolution of the set is sent to it.

FireWire (see IEEE 1394; i.Link): First common in the computer world, this 4-or 6-pin connector is a link that carries compressed digital MPEG-2 video and digital audio for recording on a hard-disk or D-VHS digital videotape recorder. Found on some digital TV displays and set-top boxes, FireWire also carries an anti-copy code and can serve as a 2-way link between various devices in a network. Not found on most A/V receivers and DVD players.

Fiber-Optic (also called Toslink): A thin plastic or glass-fibre cable that carries digital signals in an optical format via pulses of light. Uses a small, square plastic male connector on each end. Most recent A/V receivers have both Toslink optical digital as well as coaxial digital inputs. Many DVD players have one or the other (or both). No difference in sound quality between optical or coaxial digital connections, but optical links are not susceptible to hum or interference.

HDMI (High-Definition Multimedia Interface): Much smaller and more convenient than DVI, HDMI is a USB-like digital video connector that carries the same digital video signals as DVI but with the added advantage of conveying a Dolby Digital surround sound bitstream. Copy protected with HDCP so you can't pirate high-quality digital video, it's compatible with DVI through DVI/HDMI adaptors. No image superiority of one over the other. HDMI is an evolving standard and many incompatibilities in the digital "handshake" of the HDCP protection code still exist between HDMI-connected components, especially when routed through an A/V receiver or A/V processor. HDMI is not a robust system yet. Component-video can, with proper signal levels, give exactly the same quality as HDMI or DVI as long as the native resolution of the set is sent to it.

HDTV (High-Definition TV): Not a connector but part of the new digital TV standard that features increased horizontal and vertical resolution, a choice of progressive or interlaced scanning, and a widescreen aspect ratio of 16:9 (the ratio of a screen image's width to its height) that conforms to the widescreen visual format of modern movies (older analog TVs have a squarish-looking 4:3 aspect ratio). The most common HD formats are either 720p (720 progressively scanned lines) or 1080i (1080 interlaced scanned lines) or some variation of these. DVDs, although digital, are Standard Definition (480i), which may be displayed as 480p.

IEEE 1394 (see FireWire, above): also called i.Link.

Interconnects: Any set of cables or connectors that link A/V equipment of all kinds, however, most commonly the term designates low-level RCA audio and video connectors rather than speaker cables.

Jack: Any female receptacle of an audio or video connector into which the plug, or male connector, is inserted. All connectors have male and female components, RCA plugs and jacks historically being the most common on consumer-grade audio/video equipment. Sometimes the terms jacks and plugs are used interchangeably.

Mini-jack, mini-plug: A miniature connector, in mono and stereo versions, commonly found on portable audio equipment, including iPods, for headphone and line-out connections. Rare on A/V gear except for "trigger" outputs and inputs that are used to remotely activate electric screens, separate power amplifiers and subwoofers in elaborate custom home theaters and installations.

Multichannel Analog Input (see DVD-Audio, above). If your DVD player has the capability of playing back high-res DVD-Audio or SACDs, use this six-cable RCA connector set to connect to the analog multichannel input of the A/V receiver.

Phono Jack: Always an RCA connection on A/V receivers or preamplifiers for the output from a turntable's moving-magnet (MM) or moving-coil (MC) phono cartridge. Still available on up-market receivers and preamps. Don't confuse this with "Phone Plug" (or Jack), which is a larger and sturdier ¼-inch diameter connector used on consumer A/V equipment for headphones.

RCA Connector: By far the most common small audio or video connector, with a pin (male) plug and female jack. Uses 2-conductor shielded coaxial cable.

RGB: In its connector form, it routes discrete red, blue and green color signals to HD displays. Its variant, RGB+H/V, also carries the horizontal and vertical sync signals on separate connectors. Sometimes found on separate high-end video processors, scalers and projectors. More often used with a VGA connector (D-Sub-15) between computers and monitors. RGB is not inherently superior to component-video connections.

SACD (Super Audio Compact Disc; see DVD-Audio, above): a high-resolution digital multichannel audio standard developed by Sony/Philips that uses DSD (Direct Stream Digital) audio encoding. You'll need a bundled, shielded 6-cable RCA connector set to play back SACD to the A/V receiver as well as an SACD-compatible DVD player.

SDTV: Standard-definition digital TV, defined as a 480i signal (480 interlaced scan lines) presented 30 times per second.

SPDIF (Sony Philips Digital Interface): A format for exchanging digital audio signals between consumer audio gear. The actual connectors are either Toslink optical or coaxial digital (see above). Sometimes confusingly used to refer to fiber-optic (Toslink) connectors.

Speaker Cable: Available in various gauges or wire thickness, designated by "AWG" followed by a number e.g., AWG12 is 12-gauge speaker cable. The lower the number, the thicker the cable and the less resistance there is to the passage of amplified audio signals (AWG12 is thick; AWG18 is fairly thin). All speaker cable is 99.9% oxygen-free copper and is normally supplied in 2-conductor unshielded form. You'll need one 2-conductor cable for each speaker in your home theater system, except the subwoofer. A 5.1-channel system will require five separate speaker cables plus a single coaxial cable for the subwoofer (see Coaxial, above); a 7.1-channel system, seven cables plus a single coaxial sub cable. To keep electrical resistance (measured in ohms) to insignificant levels, choose the speaker cable gauge by the length of the cable run from the receiver/amplifier to the speaker. For runs up to 20 feet, 14-gauge is fine. Use 12-gauge speaker wire for long runs up to 60 feet or to err on the side of conservatism. Speaker cables do NOT need to be the same length from the receiver/amplifier to each speaker. Good generic speaker cable can be purchased in bulk. Speaker cable does not impart musical qualities to the movement of electrons, despite the fanciful claims of reviewers with hyperactive imaginations. All copper cables of sufficiently thick gauge sound identical.

S-video: A small multi-pin connector cable that carries the chrominance (color) and luminance (brightness) video information separately. Not capable of carrying HD video signals but superior to composite video connections. Use this connector for better image quality if your TV, A/V receiver and VCR has S-video inputs and outputs.

Toslink (see fiber-optic, above): A plastic fibre optical cable for conducting digital audio signals in optical form, as pulses of light.

VGA (see D-sub, above): Originally found on PCs but now found on some HDTV monitors and tuners, it uses a 15-pin D-shaped connector to carry video and sync information. If your HDTV has a VGA (D-sub) input, you can connect your laptop or PC directly to the HDTV for display purposes.

XLR (see Balanced Connector, above).

This list comprises the most common types of audio and video connections you are likely to encounter in setting up your speakers, A/V receiver, subwoofer, TV or HDTV, projector, DVD player, set-top cable box/satellite receiver, VCR, DVR and gaming console. For more detailed discussion of some hook-up problems, see the Axiom Archives.

For years conventional wisdom, even in retail shops, incorrectly referred to surround speakers as “rears,” in part because lots of audio shop owners recalled the brief era of Quadraphonic four-channel sound in the 1970s, which specified placing four speakers in the four corners of the room. Besides, “surrounds” is a less specific term than “rears,” and “sides” just doesn't cut it. As often as not, the back wall is where surround speakers often end up.

Ideal placement of surround speakers in a Dolby Digital 5.1-channel home theater setup, featuring the Axiom QS Surrounds.

The fundamental reason for side placement of surround speakers, beside the fact that Dolby Labs advise it, is that the 5.1-channel soundtracks for movies are mixed with the surround speakers above ear level at each side of the mixing theater or studio, just like in large movie theaters. Since in our home theaters or media rooms we are trying to replicate or mimic the acoustic soundfield that we experience in a cinema, and hear what the sound engineers and the director heard when they panned and mixed the directional effects for motion pictures, it's clear enough that surround speakers properly belong on each side wall of your home theater, above ear level.

Interestingly, however, there are solid acoustical reasons for this as well (and psycho-acoustical data to support it). Our ears are at each side of our head, not on top or at the back, and the pinna—the shell-like cartilage external ear—is focused forward, the better to collect lateral reflections from the sides and direct sounds arriving from the front. The brain measures the timing and amplitude differences in the sounds arriving at the left and right ears and determines the direction and location of the sound source. Any sound other than front dead center has to travel farther around one side of your head or the other to arrive at the other ear, so it arrives a few milliseconds later.

What's more, it turns out that our hearing is especially acute to these lateral timing and amplitude (signal strength) differences. In fact, research on concert-hall design has shown that it is largely the lateral-arriving sounds reflected from the sides of a space that tell our brain how big a space we are in. While sounds reflected from above and the back wall aren't entirely wasted and do contribute, it is the arrival time and amplitude differences of the side-wall reflections that are crucial elements in giving us a sense of the acoustic space, its size, reverberant character and a sense of “spaciousness.”

Some of this research came to light in the 1960s when orchestras and their governing boards pressured architects and acousticians to increase the size of concert halls by pushing out the sides of the hall in a fan shape, the better to accommodate more seats, wider aisles, generate more money, and bolster the salaries and retirement funds of the musicians. Sadly, the resulting halls turned into acoustic nightmares. Regular concertgoers, deprived of those important lateral reflections (the fan shape prevents side-wall reflections from reaching concertgoers' ears) found the acoustics of these new, bigger, fan-shaped spaces “dry” or “dead,” “2-dimensional” or worse. Attendance declined and in the case of many big-city orchestras (Toronto, New York, San Francisco), entire halls were eventually gutted and re-built, with great attention paid to retaining the classic rectangular shoebox shape or some variation thereof. In most cases, the result was greatly improved acoustics and satisfied patrons.

The lesson in all this is to try and locate your surround speakers at the sides of the listening area, somewhere within that magic angle of from 90 to 110 degrees (to the front speakers) firing across the room and a bit above your ear level, if possible. With Dolby Digital 5.1-channel movie soundtracks of all varieties, and even with lots of multichannel music or CD material processed through Dolby Pro LogicII(x), you'll experience the optimal mix of direct and reflected ambient sound. And, as many system owners have noted, the generous dispersion of Axiom's quadpolar multi-directional QS8 and QS4 surrounds allow considerable leeway in placement.

Now, it’s getting a bit confusing. If you’ve purchased an A/V surround sound receiver recently, it almost certainly has six separate channels (left, center, and right across the front, left and right surround channels to the sides, and a subwoofer channel for low-frequency effects). And if you paid a bit more, it may even contain two extra channels to process sounds for one or two back surround speakers.

Let’s sort them out.

The two competing surround soundtrack formats in which virtually all modern movies are mixed are Dolby Digital 5.1 and DTS 5.1. Each of these uses the aforementioned six channels, one of which is called the ".1" subwoofer channel because it’s limited to deep bass sounds below 100 Hz. It also represents one of the ten octaves of audible sound, hence its "5.1" label. In each system, a digital data stream of 1’s and 0’s carries all the information for all the channels over a single coaxial or optical digital cable to the innards of your receiver, which first identifies either a Dolby Digital or DTS signal, and then decodes the data, routes it to the appropriate channels, and converts it back to analog sound and music signals that can be amplified and reproduced by your five speakers and subwoofer. For the record, both Dolby Digital 5.1 and DTS 5.1 use perceptual encoding and decoding to save digital space and make all those channels manageable, as well as permitting a two-hour movie and six discrete channels of sound to be contained on a single DVD.

Recently, Dolby Labs added an extra channel to its Dolby Digital 5.1 channel scheme and called it Dolby Digital EX. Not to be outdone, DTS came up with its own version, DTS-ES. If your receiver has these modes, it will decode the small but growing number of movie soundtracks encoded with a back surround channel reproduced by one or two speakers behind the listener. If one, it’s called a "6.1"-channel system; if two, a "7.1"-channel setup. The idea of this extra channel(s) is to provide a more immersive listening experience and greater realism with more convincing surround effects. While the extra channel is not a truly discrete digital channel, it nonetheless will deliver a more seamless surround effect and better coverage, especially in larger rooms. If your receiver is equipped with Dolby Digital EX and DTS ES decoding, and you’ve added the extra one or two speakers at the back, when you play a DVD movie that’s been mixed for EX or ES, the receiver will automatically decode the extra information. You don’t have to do anything (this is good). And even if you play a standard 5.1-channel movie, your receiver will automatically extrapolate information for the extra one or two rear speakers. There is a further wrinkle with DTS, an ES mode called "ES Discrete". Some newer discs so-encoded deliver six entirely discrete channels plus a subwoofer channel. (With Dolby Digital EX, the extra channel is "matrixed"; DTS also has an ES-Matrix mode.)

If you’re old enough, you may recall that lots of movies back in the 1980s were mixed in "Dolby Surround," which used two analog channels to piggyback or "matrix" a center dialog channel and a single mono surround channel, the latter always played over two surround speakers. If you rent or own one of these old movies, you can use your receiver’s sexy new Dolby Pro Logic II Movie (or DTS Neo:6 Cinema) processing modes to simulate a digital 5.1-channel surround sound presentation from what is essentially a two-channel stereo source. And if you play a simple stereo CD or even a stereo vinyl LP, you can switch to a "Music" mode in DPL II or DTS that will recreate a six-channel surround mode. Choose the "Movie" mode of DPL II or the "Cinema" mode of DTS for old, Dolby Surround encoded movies or current television shows, or the "Music" modes for non-encoded stereo CDs or 2-channel sources. The latest A/V surround receivers have DPLIIx, which takes a two-channel stereo source and simulates 7.1-channel surround sound.

Finally, some manufacturers have developed their own proprietary multichannel processing. Harman/Kardon offers Logic 7 on most of its surround receivers, derived originally from Lexicon’s processors, which Harman owns. Logic 7 has its own Cinema and Music modes as well.

DPLII, DPLIIx, DTS Neo:6, and Logic 7 each has its own distinctive character. Depending on the source, you may prefer one over the other. I sometimes find Logic 7 to be very realistic with 2-channel Cds of classical orchestral, jazz, and opera. DTS Neo:6 tends to sound better with many pop or rock recordings, and DPLII or DPLIIx at times can be a knockout with both genres. DPLII or DPLIIx may also put too much information into the surround channels. But it’s fun to experiment and find which you prefer with which recording. Sometimes (I admit it’s rare), plain old 2-channel stereo sounds best!

Oops, I almost forgot. Most new A/V surround receivers offer a "5-channel stereo" or "7-channel stereo" mode, which mixes the left and right stereo channels from a 2-channel disc into ALL the amplifiers and speakers you’ve got running. As it turns out, it can be surprisingly enjoyable and it’s ideal for parties. No-one gets left out!

So let’s first correct that all-too-common misconception about the surround channels. Much of the A/V industry and many retailers have mistakenly come to refer to the surround speakers as "rear" channels—it's convenient, and consumers get it more easily—but in fact Dolby Labs specify that surround speakers should be mounted on the side walls, to each side of the listening area, up higher, above the level of seated listeners, just like they are in the Dolby movie theaters. In cinemas, there are typically four or more direct-radiating surround speakers along each side wall, with a couple on the back wall as well. All these surround speakers are used for movie soundtrack directional and ambient effects that immerse the listener in a believable re-creation of the events and place that are happening on-screen in a given scene. Whether it’s crickets in a summer evening, a storm on the ocean, or the sounds of artillery around the soldiers in a war movie, the output of the surround channels is an essential ingredient to the movie experience in either a theater or a domestic living room.

Axiom QS8 Quadpolar Surround Speakers, pictured above in Mansfield Beech with Light Gold Grilles.

"The QS8s are astonishing. I have never heard a speaker that better lives up to the surround paradigm." – Wes Phillips, OnHomeTheater.com

But in most living rooms or family rooms, the room dimensions are a tiny fraction of those of a commercial movie theater, and we don’t have the space (or the budget) to line our walls with multiple surrounds. Enter the dipole, bipole, and quadpole surround speakers.

To mimic the acoustic delays that occur in a big space, with a big wash of reflected sound bouncing around the auditorium, designers applied the dipole principle to domestic surround speakers, using two or more drivers in a wall-mounted enclosure firing towards the front and rear of the room. Indeed THX Lucasfilm endorsed their use in all domestic installations of THX speaker systems. However, in demonstrations of dipole surrounds, I’ve always detected a weird kind of "phasey" effect that induces in me a sense that speakers are out of phase; it may be peculiar to me (I doubt it) but I prefer multidirectional surrounds that don’t use dipole configurations. Other manufacturers picked up on this and produced "bipolar" surrounds, or some combination thereof, where the front and rear bass waves are in phase, and fire forward and to the rear, so a similar (but not identical) wash of atmospheric sounds is created. And there is no bass cancellation or null area like that produced by a dipole surround, but to the listener’s ears, the effects are very similar.

Axiom’s founder and designer Ian Colquhoun decided to elaborate even further on the dipole/bipole surround concept, producing a "quadpole" design. He placed woofers firing upwards and downwards on the top and bottom panels, respectively, of Axiom’s QS4 and QS8 surround speakers. Then he used a pair of tweeters firing at 45-degree angles, on angled portions of the speaker baffle. The result is a multidirectional-radiating surround speaker firing in four different directions (hence the moniker "quadpolar"). However, in the Axiom design, all drivers operate in phase. When this speaker is side-wall mounted, the net effect is both an ambient wash of atmospheric sound that mimics what’s heard in large cinemas, coupled with higher-frequency directional acuity provided by each QS speaker’s dual tweeters firing at diagonal angles across the listening area. In many applications, this is an ideal state of affairs, because it preserves ambient and directional effects for Dolby Digital/dts movie soundtrack playback while yielding fairly precise directional information for multichannel DVD-Audio or Super Audio CD (SACD) music listening, with an added ambient component to enhance musical "hall" sound.

Each of these approaches to surround speaker design can be quite effective, and differences are quite subtle. In some large reflective rooms, even multiple direct-radiating surrounds can be quite involving. But for versatility and ease of placement in conventional or asymmetrical setups, in my experience, the quadpolar design has decided advantages.

One of the most confusing subjects for first-time owners of surround sound A/V receivers is correctly setting the speaker and crossover menu. If you’ve ordered a 5.1-channel home theater speaker system complete with subwoofer, most of us understand that the subwoofer takes over much of the deep bass energy from the other speakers in the system. But where we all go wrong is assuming that we have to adjust the "crossover" in the subwoofer in addition to the crossover in the receiver’s setup menu. For most installations, there is just one adjustment, and it’s made in the receiver’s speaker setup menu. All A/V receivers have a single RCA jack labeled "Subwoofer Out" or "LFE Out", which stands for Low Frequency Effects, Dolby’s term for the .1 subwoofer channel.

When you call up the receiver’s speaker setup menu on-screen, there will be a question regarding whether you have a subwoofer running and what crossover frequency you want to use (some receivers may not give you a choice of frequency; they will likely be factory set at 80 Hz or 100 Hz). If you are using a subwoofer, choose the subwoofer "On" setting, and an 80-Hz crossover frequency. With Axiom bookshelf or center-channel speakers, or any other bookshelf or moderate-size two-way tower (e.g., the M40ti), set them to "Small". While you are at it, set the surround speakers to "Small" as well. In this mode, the receiver will route all deep bass frequencies below 80 Hz to the subwoofer via the receiver’s rear-panel "Subwoofer Out" jack.

Axiom's Flagship Subwoofer, the Epicenter 600 Intelligent DSP Sub, features our trademark vortex ports and an aluminum woofer, as well as proprietary algorithms to control every frequency – without distortion.

For Axiom’s larger tower speakers—the M80s, M60s, and M50s—depending on the particulars of room size, start by selecting the "Large" setting on your receiver for the left and right main speakers, and "Small" for the center and surround channels. With these settings, and the subwoofer set to "On," most receivers will route full-range sound, including deep bass, to the main left and right speakers, and bass below 80 Hz to the "Sub Out" jack on the rear panel of the receiver. (Some rooms may benefit from smoother bass by getting deep bass from three room locations—the sub plus the main left and right speakers—rather than a single subwoofer.) If running your left and right fronts on "Large" produces too much bass output, change the settings for the mains to "Small." You can also experiment with crossover frequencies, raising the center-channel crossover frequency to 120 Hz if you find that results in smoother dialog sound with less coloration. But 80 Hz is a generally desirable crossover frequency in most applications.

Make sure you connect a single RCA coaxial cable from the "Sub Output" jack to either the left or the right line-level RCA input on the subwoofer. You don’t need to use a Y-adaptor to connect both jacks. But you do want to set the subwoofer’s crossover to its maximum rotation so you remove it from the circuit. This is done to avoid "cascading" two crossovers, which might cause uneven and erratic deep bass output.

The only occasion where you will need to use the subwoofer’s built-in crossover control is when you are not using a line-level "Sub Out" connection from an A/V receiver. If you are running an older two-channel stereo receiver or an integrated amplifier that lacks a subwoofer output jack, connect the subwoofer by running the receiver’s left and right speaker cables to the subwoofer’s high-level or "speaker-level" input connectors. A second set of speaker cables would then run between the subwoofer and your main left and right front speakers. In this scenario, you would adjust the subwoofer crossover control to achieve a smooth blend between your main speaker’s bass output and the subwoofer’s deep bass output. Again, setting the sub’s crossover control to the 80-Hz position is a good place to start. If you use a crossover frequency much higher than 80 Hz, deep bass will start to be directional, so you risk hearing the subwoofer as a "source" of sound, which is what you want to avoid. Of course, if you have your subwoofer at the front of the room near your main speakers, it doesn’t matter if the sub’s output becomes directional. You can use a higher crossover frequency if you get a smoother transition between the mains and the sub.

In either scenario, a good alignment DVD such as the Sound &Vision Home theater Tune-Up disc is a useful tool for fine-tuning the balance between the subwoofer and your main speakers. The RadioShack sound-level meter is also helpful when used with the Tune-Up DVD subwoofer test signals.

There's nothing wrong with that. After all, it's an illusion of a musical event, a performance that originally was recorded live or in a studio that we're hoping to create in our living room. If two channels are enough to complete that illusion to a listener's satisfaction, then stereo is just fine. Certainly huge numbers of us grew up with stereo—multichannel surround sound at home is a relatively recent phenomenon in the history of recorded sound—and setting up just two speakers is a whole lot easier. Heck, I even know a moderately famous and multi-talented actor-director who is a fervent audiophile (clue: He wrote, starred in, and directed the movie “Buffalo '66”), who prefers to listen in mono. Now, that is eccentric!

Two Channels

I've passionately advocated the enhancement in realism possible with many jazz, classical and live concert recordings played back in 5.1 channels (or more) as processed through Dolby Pro LogicII, Logic7 (H/K and Lexicon) or DTS's Neo:6, all of which extract natural ambience or out-of-phase information that existed in the original stereo recording and route it, slightly delayed, to the surround channels. But I'd certainly admit that not every stereo recording benefits. Lots of studio recordings of rock or pop music, for example, often seem better delineated, simpler if you will, played in two channels.

Incidentally, most mainstream A/V receivers (Denon, H/K, Onkyo, etc.), when switched to "Surround Off" or "Stereo," will leave the bass management in place with the subwoofer operating, unless you go into the receiver menu and re-set the menu to Subwoofer (LFE) "Off." You might also have to change the speaker size setting to "Large" if it was at "Small." It's worth checking the A/V receiver or processor owner's manual to confirm whether the stereo mode leaves the sub operating or turns off the sub and the bass management.

Further evidence that I needed to redress any hurt caused stereo listeners by my surround setup article arrived in a post on the Axiom message boards this week:

“On setting up my M60's, I discovered that with a bit of experimentation, I could really lock in the soundstage. I decided to use the screw jacks (spikes) at the front of the M60's to angle them up a bit. What a difference! I also found that angling them in slightly towards the center had a positive impact on my listening enjoyment.”

This quote, which I've paraphrased, demonstrates just how a slight adjustment or “tweak” of the main speakers can greatly improve the listening experience. The writer went on to praise Axiom's sound quality and the exceptional value for the dollar that his system provides (it is a 5.1 channel system). And since the two main speakers form the “stage” that anchors a surround system, once you carefully set up the two front channels, it's easier to add the center, the surrounds and the subwoofer to complete the sonic “picture.”

Basic Two-Channel Setup

The goal of good, two-channel speaker placement should always be a smooth, consistent, and unbroken soundstage across the front, with a sense of front-to-back depth (when it's present on the source recording; many dry studio recordings have no depth at all). Ideally, you should get a sense that some instruments extend beyond the left-right physical borders of the speakers. With careful setup of speakers with wide and consistent off-axis radiation, and a good recording, you may hear cymbals and other percussion instruments positioned somewhat beyond the speakers. The soundstage should usually not be limited to a 2-dimensional space between the speakers.

You want to avoid the sense that you are getting sound from two boxes at the front of the room. That may happen when the two main speakers are too far apart. I don't like excessive physical separation: if you sit 12 feet back from your speakers, try separating the two main speakers about 6 to 8 feet. With direct-radiating speakers like the M60s, I usually angle them in very slightly towards the listening area (you may have seen this referred to on our message boards as 'toe-in'). You can tell when it's right because a vocalist will seem to appear, phantom-like, locked dead center between the two speakers. If you separate front speakers by more than 10 feet, it's often difficult to achieve an unbroken front soundstage.

If you can't get a convincing solid image of a singer between the main speakers, check the polarity of your speaker connections first (the positive + wire to the + binding post; and the negative wire to the negative) and then at the receiver or amplifier. If the two main speakers are wired out of phase, a central vocalist won't lock into the center. The image will seem vague or diffuse, there will be a noticeable lack of bass, and the treble may be harsh.

The Right Angle

I admit that I've never tried angling floorstanding speakers upwards, but if it helps in your particular room, try it. The aforementioned M60ti owner used the spikes at the front of his speakers to tilt the speakers back a bit. A couple of washers between the rubber feet and the bottom of the cabinet would also work but you'd need to be careful about stability.

Pulling floorstanding speakers out from the wall behind—you have to experiment with this—and having them unencumbered by large furniture at either side will usually aid in enhancing the 3-dimensionality of the image, especially if there are some walls to the left and right of the speaker locations (they do not have to be close). The walls to the sides contribute to early and secondary reflections from each speaker's off-axis sound output. These later-arriving sounds reach your ears a few milliseconds after the direct sound from the speaker and add to the “spaciousness” or “openness” of the presentation, extending the soundstage beyond the immediate left and right borders of the speaker cabinets. Toeing your speakers in a bit will reduce this phenomenon.

You can often place bookshelf speakers surprisingly close to the wall behind (as little as a few inches) with no negative effects on sound quality. That's because bookshelf speakers do not have as extended bass response as larger floorstanding speakers, nor do they sit on the floor, so the wall behind has negligible influence. Likewise, if you wall-mount bookshelf speakers using the FMB bracket, they are immune to bass coloration from the wall behind.

Cross Firing

Another approach that is sometimes effective with a corner setup is to have the speakers firing almost across each other's paths. If you were facing the corner, the left speaker would not fire toward you but straight out from the wall; the same would apply to the right speaker. In effect, you would be sitting somewhat off-axis to each speaker's radiation pattern. It takes a bit of playing with the angles, and you may have to increase or decrease the relative volume levels of the left and right speakers using the balance control or a menu in the A/V receiver, but it can sometimes be fairly effective when interior décor or room layout prevent more ideal placement. Still, compromise is a part of life, and no less intrusive in home stereo or multichannel surround setups than in other activities.

Some comments on “room treatments” are relevant. Listeners cannot expect a well-balanced loudspeaker to compensate for a barren or highly reflective room, for careless setup, or for bad recordings. Most good domestic speaker designers assume an average mix of reflective and absorbent surfaces, as Axiom does. The simple expedient of placing several area rugs (or carpeting) over a bare floor will often silence complaints of sound that is too "forward" or treble-heavy, and is far more effective in achieving smooth, balanced sound than elaborate in-room equalization programs or software.

Near-Field Listening

A different and valid approach to speaker setup that seeks to suppress or eliminate room reflections and boundary effects is called near-field listening. Essentially, it involves placing speakers –usually compact “bookshelf” models because the floor is a room boundary with its own effects—on stands almost in the middle of a room and sitting so close to them that reflections from room surfaces become insignificant. Lots of recording engineers use this approach when two small speakers are balanced on top of the recording console only a few feet from the engineer's ears.

Near-field listening isn't very room-décor-friendly but it can be satisfying in its own way, sort of like headphone playback without the peculiar inside-the-head imaging that headphones yield. Some of the “treatments” advocated for recording studio control rooms in which virtually all the wall surfaces are highly absorbent accomplish much the same thing.

In all of this discussion, no matter how you set up your speakers—and really good speakers make it a whole lot easier for the illusion to take hold--it's still the quality and realism of the music playback that matters. We talk of being “blown away” by a great experience. That's it exactly: the transcendent power of the musical illusion to sweep us into another reality and away from everyday life.

If we are being true to the goal of seeking higher fidelity, then an ideal loudspeaker should have no "sound" at all. In other words, it should be completely transparent, an open door to the musical performance. An accurate speaker's role is to replicate—precisely—the sounds of musical instruments or voices exactly as they were present in the original source recording. The speaker shouldn't add any sound of its own—it shouldn't make strings and violins sound screechy or edgy, nor should it artificially add bass emphasis to male singers' voices so they sound too bassy or "fat" (a common fault of many speakers).

So what sonic clues should immediately become evident? What attributes do we listen for, and what weaknesses should we be mindful of? Let's start with the midrange, which is where most musical content resides, and where our hearing is by far the most sensitive. (Yes, I know we all love bass, but a speaker must reproduce the midrange smoothly if we are ultimately going to like it.) If a loudspeaker nails the midrange precisely, without harsh-sounding peaks, or dips that make the mids sound muffled and distant, it will tell your ears immediately whether you will accept it as natural and "musical." If not, you'll reject it as tonally false or "colored," and music won't sound realistic. We've all heard speech and we're familiar with the sound and nuances of male and female voices. And we've all grown up hearing pop music, which mostly features vocalists or groups of singers, as well as live choruses, the latter in schools or church, or even the national anthem at sporting events. Therefore, a good place to start is with a good CD of an individual singer or a group.

If it's a female vocalist, does the voice sound smooth and clear? On the other hand, the vocal may sound too clear, with exaggerated "s's" and "t" sounds (that's called sibilance), which can tip you off to a speaker with a midrange peak that makes female voices sound sharp or shrill. Make sure you choose a recording that's smooth and natural to begin with—many are not—in order to properly judge whether a loudspeaker can accurately reproduce that voice. An older CD with a natural female vocal is Jennifer Warne's Famous Blue Raincoat. Norah Jones's voice on the 5.1-channel DVD Live in New Orleans is a current recording that very naturally captures her vocals, without excessive sibilance or brightness. Likewise, Diana Krall Live in Paris is well engineered. If you are listening in stereo, the vocal should be naturally placed with the other instruments; it shouldn't sound dull or muffled or farther back. The latter is a sure sign of a speaker's reduced or recessed midrange (sometimes termed "laid-back"), which will place midrange sounds farther away and make them less distinct.

A choral recording of men's and women's voices is an excellent test of midrange clarity and detail: Can you separate the four parts of a chorus—the male basses and tenors, and the female altos and sopranos? The sopranos are the highest-pitched female vocals; the altos are lower. You should be able to hear each section of a choir clearly. Speakers with depressed midrange response make all choirs sound somewhat muffled and blurred, wooly or "fuzzy" sounding. Almost any modern CD of Handel's Hallelujah chorus from "The Messiah" will do, but lately I've been using a wonderfully natural CD of English composer Edward Elgar's Scenes from the Bavarian Highlands, with the London Symphony Chorus and Orchestra (Chandos 9436). Try track 10, "The Dance" (listen for the triangle—it should have an ultra-clear metallic ring, which is exactly how it sounds on Axiom M22ti's) and track 15, "The Marksmen." Listen for each section of the chorus. This disc also features a very spacious and open sound with great horns, strings and percussion (try playing it back in multichannel through dts NEO6-M, Dolby Pro Logic II, or Logic 7 processors; it decodes wonderfully) and very convincing hall sound and depth. And there are loud, exciting musical climaxes, with plenty of cymbals and drums. Good speakers should remain clear and not get muddy during the loudest peaks in the music. (Incidentally, this CD is a great choice for anyone who finds some older classical works boring and ponderous, and would prefer an introduction to Elgar's richly melodic and lively 20th-century music.)

A well-recorded male vocal such as Harry Connick's voice on the soundtrack CD from When Harry Met Sally (any track except track 1, which has harsh trumpets), or James Taylor's concert DVD Live at the Beacon theater, should be smooth and natural, with no fuzzy or low bass emphasis. Speakers with an elevated upper bass hump will make most male voices sound thick or fat, rather than natural and real. These recordings also have excellent acoustic and electric bass lines, respectively, with crisp sounding cymbals and good drums. On loudspeakers with good bass response (even some bookshelf models like Axiom's M3ti or M22ti have clear, smooth bass to about 50 Hz) you can follow each individual bass note. A speaker with poor or uneven bass output will make electric or acoustic bass sound like a dull thump, with individual notes hard to distinguish.

Some classic rock recordings like Dire Straits' Brothers in Arms are very well recorded, with natural-sounding vocals, deep bass, and guitar lines that aren't harsh. Likewise Eric Clapton's Unplugged DVD is an engineering stand-out. You will likely have your own favorites that you've heard so often you'll just know when they sound "right" on good speakers.

If you are considering speakers for mostly home theater use, the same standards apply. A speaker that is smooth and accurate on music alone will be just as neutral and transparent with movie soundtracks. There is no separate category of speakers which are "good for home theater" or "good for music." The same standards of fidelity apply.

Center-channel speakers pose a particular challenge to any manufacturer, because the tonal (timbral) match between the center and the front left and right main speakers is very important. If there isn't a reasonably smooth tonal match, character's voices will shift tonality as they move across the stereo soundstage, and the seamless blend of dialog with music and sound effects will be broken. So listen to centers for any "boxy" effects. Speaking voices heard through a good center shouldn't sound like a disembodied voice inside a box. It should seem natural and not change tonal quality as the actor moves across the stereo stage from left to right, or vice-versa.

I asked Tom Cumberland, an Axiom colleague and an experienced engineer involved in the audio business for many years, how he judges loudspeaker sound: "As an electronics guy, I always listen for listening fatigue, which shows up as non-linearities in a loudspeaker's sound. With amplifiers, listening fatigue can result from distortion and other artifacts. With speakers, non-linearities show up as peaks and dips in the frequency response as well as other distortions.

"You can't just listen for a few minutes," notes Tom. "You have to listen for an hour to music or watch a whole movie. If the speakers cause listening fatigue, it will show up with longer-term exposure."

I also queried Ian Colquhoun, the founder of Axiom, on what he listens for when assessing prototype speakers:

"As the designer of Axiom loudspeakers, I am really analyzing and comparing the connections between the data from double-blind listening tests to laboratory acoustical measurements. For those of us who do extensive listening, we become adept at picking out fairly quickly when the loudspeaker is coloring the sound. For most people who do not listen to loudspeakers for a living, this process can take some time. Regardless of the experience level, however, the individual results are shockingly consistent from double-blind listening tests. An inexperienced listener, and even listeners who claim they are tone-deaf, eventually will come to the same conclusion as the experienced listener. This process lends itself to listeners becoming more and more satisfied with the sound of a good speaker over time and more and more frustrated with a bad one.

"An analysis of why this happens shows that it is related to amplitude and balance in relation to the source material. Even using source material that is colored on the original recording—and there are lots of recordings like that—it will still sound as good as it is ever likely to sound when reproduced on properly designed loudspeakers. This is because the odds of a colored loudspeaker lining up in exactly the inverse coloration of a bad recording is simply impossible in the long run. The amplitude, or volume level, has a dramatic effect on the blind listening test. Two identical loudspeakers with one set just slightly higher in amplitude will consistently result in the louder one winning the listening test. Since a colored loudspeaker will have broad variations in amplitude response throughout the audible frequency range there will inevitably be certain sections of the performance that are unnaturally louder than they should be. The inexperienced listener may conclude early on in the listening session that this is a good thing because it is a louder thing, but as various source materials are used and as various instruments or vocals on the same source material coincide with this unnaturally loud frequency region, the fatigue and the imbalance begin to become apparent and undesirable."

There you have it. Try combining the information here with some of the descriptors outlined in "Describing Speaker Sound" .

The event the scientists designed their experiments around was a concert by the Philadelphia Orchestra, carried live over multiple long-distance Bell telephone lines to listeners in a remote location. Amazingly, this occurred in the era of mono, low-fidelity 78-rpm records, long before the invention of tape recording or two-channel (stereo) LP discs, which didn’t arrive until the early 1960s.

The scientists’ assessment at the concert’s end? They concluded that at the very least, a minimum of three channels were necessary to properly convey a reasonable facsimile of the orchestral performance. Two channels, they believed, were a major compromise, often resulting in an apparent hole in the middle, with no center image. This liability destroyed the illusion and collapsed the sound to the left and right speakers.

Which Illusion Do We Want?

But what are we seeking with this addictive hobby? A window looking in on a performance, with us sitting outside the window? Or the illusion of musicians playing live in our listening room? Is the medium supposed to transport us acoustically to the event, with all the original reflections and delays of the concert hall or club intact?

To get there from here, let’s back up a bit. By way of illustration, let’s say we set up a pair of stand-mounted Axiom M22ti’s (or a pair of M80ti’s) about eight feet apart, well out from the walls and facing straight out towards the listener. A few weeks ago, I did that, sitting in the center about 10 feet back from the speakers. I played a well-recorded CD that produces an excellent sense of front-to-back depth (on speakers with fine imaging and good lateral dispersion, that is). The disc (Ariel Ramirez: Misa Criolla, Philips 420 955-2) features a male tenor up front, miked up close, backed by a choir, South American and Spanish folk instruments, harpsichord, piano, and percussion, all positioned well back of the tenor and spread across the rear of the soundstage. It was recorded in a Spanish church, so there’s all kinds of reverberant information on the disc.

When I settled into my chair in the middle of the room, the illusion was very convincing. Jose Carreras, the tenor, is dead-center, on a plain even with the speakers, with the choir and folk musicians perhaps 20 feet behind him, arrayed across what seemed to be a fairly large acoustic space. When I closed my eyes, it seemed almost real: I was comfortably seated, looking in on this performance.

Yet, if I shifted my chair a foot or two left or right, the 3D soundstage, and the perspective of the singer, choir and musicians, more or less collapsed. Because the Axiom’s lateral dispersion of mids and highs is so good—I experimented with the M22ti’s and M80ti’s—even sitting to the side, I still retained a sense of a performance taking place in a large reverberant space, but much of the depth had disappeared, and the tenor and choir seemed offset to the nearest speaker. (A balance control can help compensate for this offset—but only a little.)

Why does this happen? Mostly, because the amplitude or loudness of sounds shifts to the speaker closest to our ears when we move away from the centralized "sweet spot." Our binaural hearing is cued to these amplitude and arrival-time differences so we can quickly determine the direction of sounds and voices. This ability was crucial in our evolution, so we could detect the approach of threatening beasts and enemies in the forest. But this same ability also fundamentally compromises two-channel stereo.

Big Two-Channel Flaw

The other flaw—and it’s huge—which intrinsically limits stereo’s ability to create the sense that we’re in the same acoustic space as the musicians is that all the reverberant information contained on a stereo recording is fired back at us from two speakers at the front of the room. If you think about it for a moment, it never happens that way live in a concert hall, studio, club, or arena. Yes, sound comes from the on-stage musicians directly to our ears (and to the two stereo microphones), BUT it’s also reflected from the side walls, the ceiling and the back wall, and reaches our ears from those directions a few milliseconds later. That tells our ears and brain the size of the acoustic space, the position of the musicians within that space, and our location relative to the musicians. And it’s the directions and delays of those reflected sounds that must be preserved intact—and replayed in your listening room from the same direction. That is what convincingly recreates the illusion of the hall and space. To be fair, two stereo channels will also register those reflected sounds, but they reproduce them from the front of the room, and that’s where the stereo illusion falters.

More than Two to Tango

So where are we now? It’s no surprise that decades after the Bell Lab experiments, when movie sound and Dolby Labs engineers were doing early work on multi-channel cinema sound, it seemed logical to add a center channel. (In cinemas, this was essential for audience members seated off to the side. Without a third-channel dialog speaker, behind the screen, the actor’s voices would shift to whichever side of the theater viewers were seated on.) So naturally, when Dolby Labs developed its first consumer version of Dolby Surround, they added not only the center channel but a matrix scheme to preserve and then derive the ambient and directional information contained in the two channels, which was then rerouted to side-mounted surround speakers. Although crude, at least the reverberant reflected sounds were aimed at your ears from roughly the same direction that might have occurred in the original concert space. Moreover, the surround signals were mono—played back over two surround speakers—but mono nonetheless, quite unlike what happens in real-life concerts. Still, it was a whole lot better and more convincing than two-channel stereo.

Now, of course, with Dolby Digital/dts, DVD-Audio, and Sony’s SACD, we have 5.1 discreet channels, with embellishments in some configurations. We can add QS Multipole surround speakers at either side, which simulate the dispersion of multiple relections in real-life concerts—and they are fed by separate channels that, in many of the best recordings, are used to record the actual direction, intensity, and delays of the real-life reflected sounds.

The Comparison

Back to our experiment. When I played the CD of Misa Criolla and the Spanish choir and folk musicians on my 5.1-channel surround system (with M22ti mains and QS surrounds), and listened in Dolby Digital Pro Logic, then DPL II, the recording opened up. I seemed to be almost in that old Spanish church. It was a big improvement on stereo, and enjoyable from numerous locations in the room, but still not quite ideal. That I experienced when I put on a remarkable DVD-Audio demo disc from AIX Records (www.aixrecords.com), which contains not only 96-kHz/24-bit 5.1-channel DVD-Audio recordings with selectable "audience" or "stage" point-of-view mixes, but Dolby Digital 5.1 tracks for compatibility and video content of the performances. Even if you don’t have a DVD-Audio player yet, I urge you to try out this disc (it’s available free for a modest shipping charge from the AIX Records web site). It’s compatible with any DVD player and the Dolby Digital 5.1 audio mixes are almost as good as the 96 kHz/24-bit DVD-A mixes.

Five Channels = Ultimate Realism?

What will you hear? On the sampler disc, I heard the most realistic jazz recording of a piano I’ve ever heard. The piano is right there, in my room! And an amazing recording of an a cappella vocal group, Zephyr, done in the round, simulates the listener standing in the center, with the singers encircling him or her. If you switch to the "audience" mix, it’s as though you’re sitting in the first or second row of a small recital hall. And when you play the track of Luis Conte’s Latin Jazz Trio in stereo, it’s good—but then switch to 5.1 channel discrete, and the sound of the conga "opens up," telling your ears you are right there in the studio. What’s so realistic and wonderful about these recordings is that you can move around your room to different seats, and the realism is retained. (Keep in mind I used Quadpolar surround speakers for these tests.)

So let’s "hear" it for multiple channels for audio. Five (plus .1) almost gets us to audio nirvana. More channels will only improve things further. But the Bell Labs guys would be astonished and delighted by what’s evolved in the 65 years since their first three-channel experiments.

In closing, I should mention that Tomlinson Holman, the guru of Lucasfilm’s THX system (he’s the "TH" in the name) has demonstrated 10.2-channel sound: I heard it, and it’s fantastic. But yikes, where to put all those speakers?

But this simple label overlooks an important aspect of loudspeaker performance that becomes crucial when home theater fans want to place speakers into a secondary enclosure like a big, custom-designed wall unit with special cavities intended to accommodate floorstanding speakers.

M60 Floorstanding Speakers with front- and rear-facing ports.

Axiom M60 or M80 tower speakers, for example, have fairly tall, somewhat deep cabinets, tapered towards the rear, with typically one or more rear-facing ports. The enclosure volume, multiple ports, and narrow front baffle all contribute to smooth, extended bass response and a spacious soundstage. If you want deep bass, a relatively large enclosure is a fact of life in speaker design. That is a basic law of physics that can't be circumvented. Consequently, larger speakers occupy more space in a person's home. And that gives rise to certain issues.

Axiom customers who want to preserve domestic bliss reluctantly yield to spousal or partner requests that no speaker boxes of any sort be visible in the room where the entertainment system resides. Hiding the boxes inside a wall unit seems the perfect compromise. Customers frequently email me, asking if it's OK to go ahead and install a pair of M60ti towers in an entertainment center. Despite my advice not to, one recent Axiom customer did it anyway. He called last week and reported that his M60s sounded so much better when he pulled them out of the wall unit and listened to them out in the room. His wife's approval remained a big, unresolved issue, and we discussed alternatives (dump the wife? Just kidding. . .), including wall-mounting a pair of M60ti's or, as I suggested, suspending them from the ceiling.

Large wall units or entertainment centers are sensible solutions to house an A/V receiver, DVD player and other gear as well as the TV display. But putting tower speakers inside the wall unit will degrade and compromise Axiom's neutral and transparent sound.

Why does this happen? Much of the evidence gathered so far is based on my own observations over many years as well as anecdotal reports from Axiom owners. (Axiom intends to explore this phenomenon more scientifically and report on the findings in an upcoming AudioFile newsletter, with comparison measurements of speakers set up in a normal configuration then re-measured in enclosures or boxes, much like those one would find in large wall units or entertainment centers.)

The reason that a well-designed loudspeaker sounds neutral, natural and musical when it's heard in an ideal setup away from room corners, ultimately depends on the speaker's linearity, the technical term for the smoothness of the frequency responses that are radiated directly forward and at increasing angles to each side. The off-axis radiation at angles to each side is important because these are the sounds that are reflected laterally from the walls. Dozens of measurements of a speaker's output into the area of space in front of the speaker (the front hemisphere) show that if the frequency response of the speaker remains smooth and consistent over a broad angle, the speaker will be musically accurate and free of tonal colorations and distortions that lessen the realism of the reproduced instrumental sound.

If we listen to instruments facing toward us in a live setting (think of horns, reeds, and woodwinds), the complex wavefront that represents the sound or timbral signature of a particular instrument is composed of fundamental musical tones plus harmonics that are generated by the resonances within the pipe or tube of the instrument. This combination of tones and overtones create the sonic signature for every instrument, and even establishes the unique character to our own voice. This complex mix of tones and overtones is radiated instantly and simultaneously, reaching our ears intact. If the instruments face away from us, they sound different, because the makeup of the instrument's set of fundamentals and overtones has changed.

Instruments have far-field reflections, not near-field reflections, so if you put a musical instrument inside something, you change the radiation characteristics. You create near-field reflections that happen too soon, so the frequency response and the spectrum gets distorted. (For exactly the same reason, you don't play your guitar facing the wall.)

Loudspeakers work the same way. When the designer knows the way the loudspeaker responds over a broad set of angles in a test setting (he has examined a family of curves the speaker's frequency responses into a broad space in front of it), he knows that when the speaker is placed in a room it will continue to disseminate its energy in the same manner, so there is a high degree of probability that the loudspeaker will continue to deliver its wavefronts accurately, and it will be heard that way by listeners in most conventional domestic rooms. In the development of a loudspeaker prototype, great care is taken to investigate and correct any deviations from smoothness or linearity. Even the destructive interference and resulting frequency response glitches caused by edge diffraction from the physical edges of the speaker's front baffle or the speaker grille frame and grille material can be documented and fixed.

Knowing this, it's not difficult to understand what happens when you put a tower speaker (or a bookshelf model) inside a wall unit, credenza, or entertainment center. The surfaces in the wall unit's cavity at each side and above and below it, create a set of near-field reflections that don't exist when the speaker operates normally unencumbered by cabinetry. These cancel and reinforce at various frequencies, affecting the linearity of the system and producing all kinds of nasty anomalies and unmusical colorations.

Of course, this is a simplified explanation of how a loudspeaker propagates its sound into a room, but the message is clear. For the speaker designer, it is difficult enough to fine-tune the loudspeaker's horizontal and vertical on- and off-axis frequency responses to achieve a linear system that has a reasonable probability of delivering smooth, spacious, and uncolored sound reproduction given the speakers are allowed to operate in relatively free space in a room. Changing that formula by hiding speakers away in enclosures will undo all the efforts of the speaker's designer to create a smooth, accurate, and musical sound reproducer.

But what did he mean by the adjective "rich"? Did my understanding of "rich" parallel his? Did he mean "rich" as a compliment? (Amongst us picky reviewers, "rich" can sometimes be used as negative quality of a speaker.) What if each of us took away entirely different meanings of the same word? Endless confusion and misunderstanding might ensue. So you see the need for a standardized vocabulary used to describe particular qualities of sound from a loudspeaker, both good and bad.

This isn’t a new problem, of course, so I tried to determine exactly what he meant by "rich". Turns out that he meant a full, rounded sound with lots of deep, sonorous bass (more adjectives!). I pointed out that while a fine concert hall and a good recording should preserve and even enhance those qualities, a "neutral" and "linear" speaker will also reproduce them (given that the speaker has smooth, extended bass response) but that the speaker shouldn’t by itself confer a "rich" sound on all music played through it. If it did, that "richness" could become a tiresome bass "coloration": it might sound great on some music but not so good on other types. In fact, among reviewers, "rich," "ripe" or "chesty" is often used as a criticism for loudspeakers that have too much upper bass emphasis, which give male voices a "fat" unnatural coloration.

What follows is a list of standard terms that have evolved from years of loudspeaker listening tests in which I participated, conducted at Canada’s National Research Council (NRC) acoustics lab. I’ve taken the list from forms originally compiled by Dr. Floyd Toole during his long tenure at the NRC Acoustics Division for use in subjective double-blind listening tests, as well as additions from my own notes during those tests and those of other long-time reviewers, including Ian G. Masters. The forms and adjectives we used were to solve this very problem, because sometimes reviewers can become almost poetic in their descriptions of loudspeaker sound, as if the speaker were a musical instrument in and of itself! For instance, does a term like "chocolaty midrange" have meaning for anyone other than the writer who used it? Does it mean that the sound is smooth, thick, or dark? And is it a criticism or a compliment? Who knows?

Here are some common terms to describe loudspeaker sound. "Forward" indicates that vocals, male and female, tend to be very present, almost as if the singer were standing in front of the plain of the speakers. It can be a negative term, too—if singers sound too close up it may mean the midrange is boosted or exaggerated. The opposite is "recessed," which means that midrange sounds like singers and choruses seem to be farther back, a bit distant-sounding and well behind the plain of the speakers.

"Spacious" and "open" and "airy," all positive traits, describe the sense of space present around the instruments and singers; it relates to the speaker’s presentation of the stereo "soundstage" (the three-dimensional positioning of the instruments across an imaginary stage) in addition to how well it reproduces the ambient sounds present in the original recording. The opposite is "closed," "muted" or "dry," which indicate the midrange and treble are rolled off or depressed and dull.

Words like "sibilant" mean the speaker has a midrange/treble peak that emphasizes the "sss" and "ttt" sounds of singers’ vocals. The same speaker might also be a bit "bright" (a little treble emphasis) or quite "strident" (way too much treble output, making brass and string sound shrill or harsh).

"Thin" means the speaker has little or no bass output, while "boomy" means it has too much bass that dominates its sound. "Punchy" can be quite pleasing and powerful upper bass, like a disco, but no really deep bass. "Muddy" or "muddled" means the midrange isn’t clear; that it’s hard to separate the distinct contributions of male and female singers in a chorus.

If a speaker has real problems in the midrange, either a big "suck-out" or valley or other uneven response, terms like "boxy" (vocals sound as if the singer were inside a box) or "honky" are useful. Another common coloration is "nasal," which describes what a midrange peak does to vocals, like what happens to your voice when you cup your hands around your mouth while you’re speaking.

Now that you are armed with the right descriptors, you can analyze the sound you hear from speakers in a store demo, at a friend’s house (be careful with words like "honky" or "boxy" around friends!) or from your own loudspeakers. Go ahead, try these terms out on our message boards!

Until Dolby Digital, there had been little change in movie sound for almost 20 years. Dolby Surround, an analog matrix system based on two stereo channels with a phase-inverted mono surround channel and a center dialog channel had been around since 1976. (A matrix uses phase-flipping to piggyback or encode extra information on top of two main stereo channels.) Consumer versions of Dolby Surround decoders kept home theater enthusiasts entertained well enough. Although the introduction of Dolby Pro Logic (DPL) dramatically improved the separation of the center channel from left and right mains by as much as 30 dB, as well as the front-to-rear separation by a similar amount, DPL was still based on a two-channel analog matrix. In fact, it was THX that invented the “decorrelation” of the surround channels that in effect created a kind of quasi-stereo signal from the mono surround. But DPL’s surround channels were still “band-limited,” with treble severely truncated above 7,500 Hz, and it remained a mono signal.

But the launch of DVD changed everything because it provided a high-quality digital medium that could digitally store not only all the video information but the six discrete digital channels that comprise the Dolby Digital and dts data stream. With proper decoding, consumers could simulate the cinema multi-channel experience in their living rooms with unprecedented accuracy. Moreover, DVDs could be mass-replicated inexpensively. The difference in sound quality between analog, matrix-based Dolby Pro Logic and Dolby Digital 5.1 was as dramatic as the difference between vinyl Lps and the CD. The improvement in fidelity, dynamics, and overall realism was immediately audible to anyone with normal hearing.

The turf war between Dolby Digital and dts in commercial movie theaters had been settled, with the majority of film distributors and studios releasing major film prints encoded with both systems. Eventually, Sony entered the commercial cinema market, with its SDDS digital multi-channel system. Movie exhibitors installed one or more of the systems (Dolby and dts have similar numbers of theater installations worldwide; Sony uses its own system in its theaters) and film prints were usually supplied encoded with all three systems.

Unfortunately for dts, however, the introduction of DVD mandated Dolby Digital as part of the DVD standard, with dts as an “optional” system available at the discretion of the DVD’s producer. This meant that any movie transferred to DVD had to carry a Dolby Digital soundtrack, with dts as an option. Dolby Digital, by the way, doesn’t always mean 5.1 channels. A DVD movie can be encoded in Dolby Digital mono or stereo, in which case a consumer decoder will decode it in Dolby Digital Pro Logic (or in ProLogic II, if your receiver is so equipped) or, with vintage re-releases, in Dolby Digital mono.

Dolby Labs recently introduced a further enhancement of Dolby Digital called Dolby Digital EX (or THX Surround EX), which in addition to the usual side surround channels adds a back (rear) surround channel that’s encoded using a matrix system like the “old” Dolby Pro Logic. Any receiver or processor that supports these formats also decodes DTS’s 6.1-channel version of EX, called DTS-ES. In the last year or so we’ve seen the introduction of Pro Logic II (DPL II) a much improved version of Dolby Pro Logic, which decodes Dolby Surround soundtracks in a manner that brings them remarkably close to true Dolby Digital. (I wrote in detail on DPL II in the April issue of the Axiom AudioFile; go to axiomaudio.com/archives). DTS’s version of DPL II is Neo:6; it is very similar and, like DPL II, creates surprisingly natural-sounding multi-channel playback from conventional stereo compact discs or other 2-channel sources.

I’ll save the explanations of the new multi-channel audio surround formats—DVD-Audio and Sony’s Super Audio CD (SACD)—for an upcoming AudioFile.

A room's particular dimensions—indeed, the arithmetic multiples of its height, width, and length—plus its unique mixture of hard (reflective) and soft (absorbent) surfaces will have profound effects on the quality of the sounds you perceive from your multichannel home theater or simple stereo music system.

There's a lot of confusion about just what constitute ideal room acoustics. The subject has lately been receiving thoughtful discussion on the Axiom web site's message boards. A recent visitor to those boards posted some important questions:

All good questions. For those who have the luxury of actually building a room dedicated to home theater, who can choose the dimensions in advance, the "golden ratios" cited above will go a long way to minimizing those pesky standing waves which, in lots of rooms, can make low bass disappear in some parts of the room, while delivering overwhelming bass at other locations.

The idea of the golden ratio is to find a combination of height, width, and length wherein the room dimensions are not arithmetic multiples of each other. The worst sort of room would be a perfectly square cube. An asymmetrical room, where no single dimension equals or is a multiple of any other, would approach the ideal.

Unfortunately, most of us are stuck with the existing room dimensions and room shapes supplied with the house or apartment we live in. Short of demolition, they can't be easily altered. So we accommodate the room by adjusting the location of the subwoofer and/or moving the listening seats, in order to achieve the smoothest, deepest bass available to a few audience members on the couch and nearby chairs.

But room reflection and absorption is of equal or even greater importance. Too many reflections can inhibit dialog intelligibility and make an otherwise smooth, linear and natural-sounding loudspeaker uncomfortably shrill or bright. Conversely, an excess of soft and absorbent surfaces—too many draperies, upholstered chairs and sofas, and treated wall surfaces—can make a room unnaturally "dead," with none of the spacious and airy qualities that make live music seem real. This also applies to film music scores that form the background of virtually every movie soundtrack.

In large cinema auditoriums, of course, dialog intelligibility is paramount. You can't have 500 audience members lining up requesting ticket refunds because they can't understand the movie dialog.

Consequently, commercial cinemas use big horn-loaded center-channel speakers behind the screen with carefully controlled directivity to overcome the unnaturally over-damped environment. These offer broad horizontal coverage and narrow vertical dispersion—the latter to prevent ceiling bounce that would inhibit dialog clarity. This is not to suggest you should use a horn-loaded center channel speaker in your home theater. In fact, the results would be negative because the grossly colored midrange and treble of the horn would be overwhelmingly inaccurate and very noticeable in a smaller and normally-damped room, like a normal living room. You'll get much more natural-sounding dialog with a conventional non-horn center-channel speaker. Large cinemas also use upholstered seating and treated walls to further aid absorption and inhibit sidewall reflections. The rows of surround speakers down each sidewall supply whatever ambience the movie's director and sound engineer desire.

Remember, too, that the distances involved in large movie auditoriums are much greater than in a typical living room or dedicated home theater. Sounds travel at about 1 foot per millisecond, so some reflections in a typical living room have far less negative potential than in a big movie auditorium. Indeed, for domestic rooms, you want a mix of absorptive and reverberant characteristics.

The M22ti in the anechoic chamber at the National Research Council – literally, a room with no echoes. This room
would be terrible for listening to music.

For music listening in multichannel Dolby Digital, DVD-Audio, SACD (or in stereo), the walls to each side of the main speakers should have some reflective qualities. The scientific reason for this comes from some uniquely Canadian research on loudspeaker dispersion and controlled subjective listening conducted at the National Research Council (NRC) in Ottawa over many years. In double-blind listening tests, the speakers that were rated the most "spacious, airy and open-sounding" and thus, more natural, had lateral off-axis responses that most closely approximated the on-axis frequency response. (The results correlated very well with precise anechoic chamber measurements of a speaker's lateral dispersion.) It was the secondary reflections (from the side walls) that reach your ears a few milliseconds after the direct sound that greatly influenced the subjective impressions of the speaker's performance. If these side-wall reflections are absorbed, the spacious character of the reproduced sound will be lessened.

It's always something of a trade-off between movies and music. Too lively a room, acoustically speaking, will result in too many reflections that may affect dialog clarity. On the other hand, you do want to preserve those lateral sidewall reflections from your main speakers because those will add to the spaciousness of music and movie scores.

The answer to this is to have a reasonable mix of domestic furnishings that reflect and break up sounds as well as providing some absorption. Indeed, a typical North American living room—with carpeted floor, fabric-upholstered furniture, drywalls at the side with some shelves, bookcases, and some fabric window treatments—usually results in a room that works well acoustically for both music and home theater. It's easy to get obsessive about applying special "treatments" to a home theater, in the misguided belief that this will bring huge gains in sound quality. I recently asked Ian Colquhoun, president of Axiom and chief designer of Axiom speakers, to voice his views on the subject:

"The biggest mistake I've seen people make is their getting compulsive or fanatical and building special damped and/or reflective rooms for their home theater. I have been in some of these rooms (costing up to $250,000, and built by so-called professionals) and they are horrible-sounding. My theory is that we live in known environments and we are used to hearing sounds in these environments. For example, consider the sound of an acoustic guitar or even a clinking of wine glasses. We know what these sound like in our living rooms and outside. All these sounds become references of what we think these events should sound like. If you re-created these sounds or events in a "special" room, they would sound different, and hence unnatural. So avoid the danger of listening-room obsessiveness and don't change your room very much. I would suggest starting with small tweaks to get the bass right and the treble natural and clean-sounding, but don't go overboard or you can create an unnatural and hence bad-sounding room."

To that end, large areas of bare tile or hardwood floors without area rugs should be avoided, as should big expanses of glass and brick, or other highly reflective surfaces. But even these can be modified with attractive fabric wall hangings, ornamental carpets, or curtains.

And what of "bass traps," those expensive padded cylinders and screens that are sold to naive audiophiles and claimed to absorb problematic standing waves in the low bass? For the most part they don't work, because the wavelengths of low bass frequencies are so large that any "trap" would have to be of ungainly dimensions to become effective. They can be built (there are several in the NRC's listening room) but they are large and ugly. No domestic partner, no matter how tolerant, would put up with them.

So there you go, Danny Decorators, a little holiday project for the whole family: scatter a few throw cushions about the room to soak those nasty reflections.

But it's also a term that's become somewhat debased through casual usage. What may be a reference to one person may not be to someone else. One record label and more than a few brands of speakers and electronics have made the word part of their company names, the connotation being that their products may be used as a benchmark of sound quality.

But what exactly is a reference? Should it not reference the sound of live music? Historically, in audio circles, the word has its roots in recording studios. The term reference monitor usually applied to a large bass-reflex speaker commonly found in lots of studios, often wall-mounted and facing the recording console. In bygone days in North American studios, those were often big JBLs like the L112. Such speakers were not the most tonally accurate, but they could withstand the rigors of 24-hour mixing sessions at extremely loud levels without damage, one of the standards that any studio monitor has to meet.

Does a Reference Recording Exist?

The issue of reference becomes especially thorny when you refer to a particular disc or recording. Apart from advocating a few albums by some famous artists of wide general appeal (Norah Jones, Alison Krauss and Union Station, James Taylor and Diana Krall, to cite a few examples), I tend to be wary of suggesting specific CDs because there is such wide variance in musical taste. Those artists are fairly safe territory because they are unlikely to offend and the recordings are, by general consensus, well engineered. But what may be a reference for you just may not work for me.

During many years of double-blind speaker tests, various rock, pop, jazz, and classical recordings were tried out to see which material was more useful in spotting typical loudspeaker coloration and distortion. It turned out that the classical recordings were more reliable for quickly differentiating good from bad speakers, partly because a large orchestra with chorus covers such a wide range of musical frequencies and harmonics.

With a few exceptions, I don't generally use rock music to test speakers, partly because I grew up mostly listening to classical, jazz and acoustic music and vocals. I have never accommodated the distorted electric guitar sound (I never understood the reverence for Jimmy Hendrix's playing). But if you grow up listening to a lot of rock n' roll, you may know that sound really well and it may be useful for you to make accurate judgments of speaker sound quality. If you've played or listened to a Stratocaster, then I figure you likely know and appreciate when a good speaker accurately reproduces it. – A.L.

In U.K. or European recording studios, the reference was more often than not a speaker from Tannoy, Spendor, Rogers or Kef. There are also some brands of studio monitor speakers like Urei that are unknown to consumers because the company never built speakers aimed at the hi-fi audiophile market. For example, I remember the first time I saw a tiny speaker called an Auratone, perched on either side of a recording console in a big Toronto studio. The Auratone was, and is, used to simulate the playback quality of a typical boombox or mediocre car radio. Engineers use it to check the mix of a pop or rock recording to see how it will sound on a truly low-fidelity speaker. For the engineer who used an Auratone, it was his reference. (To me, it just sounded lousy). Studio monitoring references seem to go in and out of fashion. For some time in the 1980s the Yamaha NS-10, a small two-way bookshelf speaker, was a common sight in many studios, usually with a piece of Kleenex scotch-taped to its tweeters to lessen its elevated treble output.

Occasionally, a high-quality speaker designed for consumer audio actually makes its way into a recording studio and becomes a reference. That's been true of several Axiom speakers as well as a couple of models from other Canadian speaker manufacturers.

About 20 years ago, the CBC (the Canadian Broadcasting Corporation, the federally subsidized state radio/TV broadcasting system in Canada ) made a concerted effort to use scientifically controlled testing to find a tonally accurate speaker for control-room monitoring of live concert and music broadcasts. Using the NRC listening and measuring facilities in Ottawa, various listening panels of CBC music producers and broadcast recording engineers did many rounds of listening tests, all supervised by Dr. Floyd Toole, the resident NRC scientist and psycho-acoustician in charge of the Acoustics division. These tests included many of the pro monitors popular at the time (some of which did poorly in the double-blind listening tests) as well as domestic speakers from Canada, England, the US and Japan. At the end of the many rounds of tests, several Canadian speakers, an American one, and a few British models did well. The CBC recording engineers could then choose from a refined group of accurate reference loudspeakers.

In most enthusiasts' homes, however, a "reference" loudspeaker is simply the speaker they purchase and are happiest with for an extended period – and that may include some old and flawed speakers. They become devoted to the sound they've heard for years and consider it their reference, even though that sound may be wildly colored and inaccurate (I won't mention brand names so no feelings will be hurt).

However, once they hear truly linear and musically more accurate speakers like the AxiomM60s, M22s or M80s, etc., it's often a revelatory experience because they realize how much speaker design has progressed since the '50s, '60s and '70s. They may be astonished at the degree of realism and sonic nuance provided by well-designed modern speakers and of how much detail and spatial information they were missing listening to their muddled old "reference" sound.

Aldo Nova (seated) and Ian Colquhoun in Aldo's recording studio. Aldo has the M2s, M3s and M22s in his studio. Axiom speakers were also the reference speakers at the world famous Le Studio, north of Montreal.

Of course a reference speaker must be one that naturally and convincingly reproduces the sounds of musical instruments and voices. If you already own Axioms, you already know what speaker attributes like "transparent," "neutral" and "detailed" mean as they describe sound quality. You've likely spent hours and hours listening to your favorite recordings on those particular speakers and they have become your standard of fidelity, the benchmark against which you'd measure the sound of any new speaker. It's the neutral quality of the speakers that let you sort out good from bad recordings, an ability that defines true reference sound quality. A great speaker is one that becomes a transparent window to the quality of the original source recording-good or bad. It shouldn't add or subtract any timbral or tonal traits of its own to the playback sound. It should not function as a quasi tone control, covering up flaws in a recording. Nor should it artificially emphasize bass content, unless the recording itself has heavily mixed bass (plenty do).

Looking at the progress of speaker design over decades, it has been a gradual process of refinement towards a goal of transparency and neutrality, and this trend will undoubtedly continue. When the speaker stops getting "in the way of," or impeding, the music, then it has attained true reference status.

Although it's not the easiest thing to comprehend, doubling the amplifier power does not double the loudness. In the above example, the sound from the speakers would not be "twice as loud"; it would only be "a little louder," an increase of 3 decibels. How loud is that? Hearing tests with large groups of people have revealed that a one-decibel (1 dB) change in loudness is approximately the smallest audible step that the average listener can detect, so an increase of 3 dB most listeners term "slightly louder."

So why doesn't that 100-watt amplifier always sound twice as loud? Because the acoustic decibel—the decibel (dB) being the unit of measurement used worldwide to quantify the acoustic loudness of sound—has a peculiar relationship to amplifier power output measured in electrical watts. That relationship is called "logarithmic." If that word gives you an instant headache (nightmares of high-school math), then here's a simpler explanation:

If a sound gets louder by 3 decibels or "slightly louder," it takes twice as much electrical power from your receiver or amp to produce that modest increase. Therefore, a 100-watt amplifier will produce sound only slightly louder than a 50-watt amplifier.

Incidentally, if you'd like a kind of immortality, be terribly clever and work out a system of measurement. It may be named after you. The "decibel," one tenth of a bel and named for Alexander Graham Bell, recognizes his contributions to the understanding of sound. Likewise, we have to thank James Watt, Georg Simon Ohm, and Heinrich Hertz for their contributions to the industry. And then there's the Lofft, a measurement of neighbors' tolerance to testing new speaker systems . . .

So far, so good. But what if it's party time, and you're listening to music "very loud," a level defined as about 90 dB Sound Pressure Level (SPL), and your speakers are gobbling up swings of 15 to 20 watts per channel on those musical peaks.

Drink in hand, you advance to the volume control on your receiver thinking, "I'll just crank this up to make the music twice as loud," and you turn up the volume control until there's a 10 dB increase in the sound level. Now your party-time goal of "twice as loud" will make huge electrical demands on your nice little multi-channel receiver or power amp. The receiver must deliver ten times as much power to double the subjective loudness. Between 6 dB and 10 dB is double the volume level, where 6 dB is four times the power and 10 dB is 10 times the power. In the aforementioned example, the amp must produce 150 to 200 watts per channel for those peaks in loudness. Therefore, every 10-dB increase in acoustic loudness—from 80 dB to 90 dB, or 90 dB to 100 dB—requires ten times as much electrical power in watts.

That's all very well if you have a monster amplifier or multi-channel A/V receiver with huge reserves of power output (most of us don't). If not, watch out. Your receiver or amp may "clip" or distort (or both), which will put a clamp on the output of the amp. When you push your amplifier into overload or "clipping," several things may happen. First, the top and bottom of the waveforms (representing the audio signals) are clipped off, generating distortion. Next, the amplifier's protection circuits are activated, removing those portions of the signal that are causing the overload, generating distortion. And finally, the amplifier's power supply may fluctuate according to the demands of the music signals.

Not everyone is affected by this scenario, of course. Some people (increasingly few, it seems) don't listen to loud music. They like background levels, and with average speakers, background levels demand 1 watt or less of amplifier power. Or they may have very efficient speakers (Klipsch, Cerwin-Vega, Tannoy, and the like) that will play extremely loud using modest amplifiers, the trade-off being a very large degradation in tonal accuracy, a definite harshness, and a complete loss of off-axis performance that accompanies horn-loaded designs. But in many situations, speakers will be damaged and distorted sound will offend many ears.

No discussion of decibels, acoustic loudness, and electrical watts is complete without an explanation of loudspeaker "sensitivity." (Another way to define a speaker's sensitivity is to look at how efficiently the speaker converts electrical power, in watts, to acoustic sound output in decibels.) Let it be said in a general way that speakers are not very efficient or sensitive devices. They need a lot of electrical power input to produce relatively little acoustic output. Nevertheless, speakers do vary quite a bit in sensitivity.

To determine a speaker's sensitivity, we feed the speaker with 1 watt of amplifier power, using a test signal of pink noise, and measure in decibels how loud the sound is at a distance of 1 meter (about 3 feet). A lot of domestic hi-fi speakers measure in at about 89 or 90 dB SPL at 1 meter. Larger speakers, with bigger woofers and more drivers, typically produce greater acoustic output; smaller bookshelf models have to work harder, and their output is typically less, often between 86 and 88 dB SPL at 1 meter.

Placing the speaker in a room helps (the walls, ceiling, and floor reflect and reinforce the speaker's sound), adding about 4 dB to its output. For example, a speaker like Axiom's M80ti has a measured sensitivity in an anechoic chamber of 91 dB SPL at 1 watt at 1 meter. But putting the M80ti in a room raises its sensitivity rating to 95 dB SPL at 1 watt, 1 meter. A 95-dB sound level happens to be "very loud," as most of us would subjectively describe it. And it is—from 3 feet (1 meter) in front of the speaker. But let's move our listening seat back twice as far, to 6 feet. Guess what happens? We instinctively know that sound gets weaker as the distance from the source is increased, but by how much? A formula called the "inverse square law" tells us that when the distance from the source is doubled, the sound pressure weakens by 6 dB. Among sound engineers, there's a common saying: "6 dB per distance double." So at a 6-ft. distance, the M80ti is now producing 89 dB. Now let's double that distance again to 12 feet, a fairly common listening distance. The speaker now produces 83 dB, which isn't all that loud at all. And if you sat 24 feet away, a not uncommon distance in big rooms, the speaker would produce 77 dB SPL.

But what about stereo, I hear you shout. Here's another oddity of loudness and the decibel. When one speaker is producing a level of 90 dB, adding a second speaker playing at the same level only increases the overall loudness by 3 dB! (The loudness does not double!). So the two speakers in stereo produce a loudness level of 93 dB.

So adding a second M80ti will raise the loudness at 12 feet from 83 dB to 86 dB. And don't forget we're still using 1 watt of amplifier power output into Axiom's most sensitive speaker. But how loud are real-life instruments, orchestras and rock bands? Now, while 86 dB SPL is "fairly loud," it's not nearly as loud as what you might hear from a good seat at an actual rock concert or from an orchestra or pianist in a concert hall. A solo grand piano can reach peak levels of 109 dB SPL, a full orchestra and chorus in a concert hall will measure 106 dB, and a rock group, 120 dB SPL. Now let's try and get our peak speaker sound levels to 96 dB, "twice as loud" as our 86-dB listening level. That isn't that difficult because right now we're only using 1 watt per channel to drive the M80ti's to 86 dB. So we'll need ten times as much power, or 10 watts, to reach 96 dB. Big deal. We've got lots more.

But things begin to change, and rather dramatically. Let's push the M80ti's to what we might experience from a solo grand piano, 109 dB. We're at 96 dB with 10 watts per channel. Let's go to 106 dB. So that requires 10 x 10, or 100 watts. Close, but not quite there yet. Just 3 dB more. Remember, we have to double the power for a 3-dB increase in sound level. So 100 watts becomes 200 watts. Yikes! Our receiver has only 110 watts maximum output! We've run out of amplifier power! And what about the rock concert? Let's lower our expectations and aim for 119 dB. Going from 109 dB SPL, which needs 200 watts per channel, to 119 dB SPL (get out your ear plugs) is another 10-dB jump and—you do the math—that requires 10 x 200, or 2,000 watts per channel!

From all this you can see the huge power requirements inherent in reproducing real-life acoustic sound levels in average or big rooms. The M80ti's are tested to levels of 1,200 watts of input power so they come very close. But the truth is that if we are seeking real-life acoustic sound levels in our listening rooms, there's a very persuasive argument for very large, powerful amplifiers. And if your speakers are less sensitive (and many are), then the power demands rise even more dramatically. Sizeable rooms and greater listening distances will also increase power demands tremendously.

And what many of us don't realize until we hear it, is that clean undistorted loud sound often does not sound that "loud." The key here is that in most or our home listening, there are small amounts of distortion caused by a lack of dynamic headroom (but more on that next month). It's the distortion that makes it sound "loud" in a domestic setting. To remove those distortions and increase dynamic headroom relates to even more power. We've become accustomed to accepting some distortion with our reproduced music, because all amplifier's distortion ratings gradually increase as they approach their output limits or slightly clip the audio signals. When that happens, we turn down the volume, because distortion starts to intrude on our listening pleasure, and it sounds "too loud."

The lesson in all this is that you can never have too much power, and that big amplifiers rarely damage speakers. Little amplifiers driven into clipping burn out speakers. In the scheme of high fidelity, that last barrier to realism is having enough power and being able to approximate real-life loudness levels.

But if you move up really close to an electronic image display and use a magnifying glass, you can see the tiny individual squares of red, green, and blue “pixels” (short for “picture elements” in modern video-speak) that comprise the image. The pixels are actually square or rectangular in new technologies like LCD (liquid-crystal display), plasma panels, and in DLP (digital light processing) or LCD front and rear projection sets. And the smaller the pixels, and the more of them there are distributed vertically and horizontally across the face of the screen, the greater the “resolution” or detail we will see in the image. (On the old but familiar CRT picture tube TV, the picture elements are groups of round red, green and blue phosphor dots that glow when the electron beam in the tube strikes them.)

How Many Pixels?

LCD, plasma, and DLP devices are all called “fixed-pixel” displays because the panel has a predefined and fixed number of pixels in its display format. Knowing the number of pixels in each direction (horizontally and vertically) will tell you how sharp an image it will produce, as well as whether it will display a true High Definition TV image or only Standard Definition, both of which are part of the new digital TV standard. The pixel count will also affect the cost. Lower resolution costs less; higher resolution costs more, sometimes a lot more. And don't make the mistake of thinking that just because a TV is labeled “digital” means that it is capable of producing a high-definition picture. Within the new digital TV set of standards, there are three levels of resolution permitted: Standard (SDTV), Enhanced (EDTV), and High Definition (HDTV).

Going Native

If you are considering purchasing a larger screen and/or a High Definition TV (HDTV), there is a phrase describing potential image clarity that you must understand. That term is “native resolution,” and it refers to the maximum degree of clarity that one of the new digital TV formats is capable of displaying. Native resolution of a fixed-pixel display is defined as the total number of horizontal pixels across each scanning line by the total count of vertical lines stacked top to bottom. For example, a Standard Definition fixed-pixel display would have 704 pixels across each of 480 scanning lines (704 x 480) and that would represent a squarish 4:3 aspect ratio screen shape, the image shape in which virtually all TV programs were photographed until the advent of HDTV, which, as part of the HDTV standard, requires a “widescreen” aspect ratio of 16:9, similar to that of most commercial movies.

As our TV system gradually converts from analog TV transmission and display to an all-digital system, a process that will continue until 2006, Digital TV allows for three standards of “definition” or clarity, two of which encompass High Definition TV. Standard Definition, as explained above, is equivalent to 480 interlaced horizontal lines (480i) stacked from the top to the bottom of the screen. The “interlaced” lines mean that the image (a frame) is made up or alternating fields of 240 lines that are scanned across the screen every 1/60 th of a second. As the fields combine or “interlace” on the screen, a full frame of TV in Standard Definition is presented.

DVD Resolution

Stored on a DVD is an MPEG digital bit stream representing the video. Older DVD players would output only 480i images from a DVD, because most older analog TV sets would only work with a 480i input. However, even inexpensive new DVD players now have internal circuits that will output the DVD's video in either 480i or 480 progressively scanned lines, known as “480p.” This is called Enhanced Definition, and gives a smoother more film-like look, with no visible scanning lines. Any fixed-pixel display will display this standard, so when you see a display described as having a native resolution of “800 x 600” pixels, you know that it has enough resolution to extract virtually full clarity from a DVD player that outputs a 480p, progressively scanned image. That resolution is not high enough to display full HDTV, but it's nearly enough to capture every line of a wide-screen DVD, which calls for 852 x 480 resolution. Put another way, the resolution would measure 852 pixels across each of 480 horizontal lines scanned sequentially from top to bottom. Typically this is the resolution of the least expensive plasma and LCD thin-panel displays, as well as inexpensive DLP projectors that use the 800 x 600 DLP chips.

In practice, most of these displays will look quite detailed with DVD playback and even HDTV signals that are “scaled” or down-converted to fit the display's 852 x 480 native resolution. However, such a display or projector will not let you view true High Definition signals in their original resolution.

To take full advantage of HDTV's ability to render spectacular clarity and detail, you must find an LCD, plasma, or DLP device that has a native resolution of either 1,280 x 720 pixels (720 lines progressively scanned with a widescreen 16:9 aspect ratio) or “1080i” (1920 x 1080), which represents a 16:9 widescreen image with 1920 pixels across each of 1080 interlaced scan lines. These are the only two High Definition formats defined by the HDTV standard. All network broadcasters use one or the other for their HD programs. For instance, ABC and Fox broadcast in 720p, while CBS, NBC, and PBS use 1080i. Likewise, cable and satellite networks will use one or the other: HBO, HDNet, DiscoveryHD, and Showtime use 1080i, whereas ESPN uses 720p. Broadcasters choose one or the other for different reasons. Progressive scanning (720p) produces a smoother, more film-like look, but a 1080i image actually contains greater detail. Though it has fewer lines, the native progressive scan format (720p) eliminates motion artifacts that originate in interlacing. For subject matter that contains a lot of rapid motion--Monday Night Football, basketball or hockey games, for example--720p will produce a clearer, more stable picture than 1080i. Alternatively, for subject matter that has very little motion, 1080i is capable of rendering more picture detail. And because 720p has the highest data bandwidth and horizontal scan rate, it usually means that 720p programming is converted or “scaled” to 1080i for transmission (it occupies less digital “space” than 720p).

When you choose an HD display, it must be able to receive and display both of these formats, either natively or by converting (scaling) the incoming HD signal to the display's native resolution. For example, a 1280 x 720 fixed-pixel LCD or plasma panel or DLP projector will have an internal scaler that will convert every incoming video signal so that it “fits” its 1280 x 720 native resolution. How well the internal scaler or converter does this may vary from one brand of set to another. And many outboard HDTV digital cable boxes and satellite tuners can be set to output their signals to exactly match your HD display's native resolution. Sometimes your HD set's internal scaler may do a better job than the outboard cable box or receiver at converting, say, 1080i to 720p, or 480i to 720p. In other cases, there may be little or no difference. You can find out with a bit of experimentation, but that is a subject for another newsletter. You can get a quick fix on this by viewing a display in a store with a variety of different input signals, including analog cable and regular broadcast TV, as well as DVDs and High-Def signals. Of course, it's difficult to do that because retailers love to showcase their new sets with HD programming so the image has the greatest impact. But if you ask, most stores will switch to a local cable or broadcast feed that will give you some idea of what you'll see viewing regular analog TV signals. And be prepared to become an HD snob. Once tasted, HD images are very seductive, and it's hard to go back to viewing “old” 4:3 non-HD signals. But each year brings more and more HD programming, so your care in understanding and choosing the right fixed-pixel display now will assure you of beautiful HD images in the future as more and more High-Def programming becomes available.

Q. When I compare different brands of A/V receivers, one is rated at 80 watts per channel into 7 channels, the other at 100 watts per channel. How important is the difference in power output?

A.   Although it seems logical that a receiver with 100 watts per channel represents a 25% increase in power output over one with 80 watts per channel, and therefore would sound 25% louder than the 80-watt-per-channel model, this difference in power output would be virtually undetectable. Practically speaking, the 100-watt receiver would only be about 2% louder, an increase in sound level of a fraction of a dB, which is normally not audible except with a test signal. To actually make a difference in perceived loudness that is easy to hear requires a 3-dB increase—a difference termed "somewhat louder" by most listeners—and you would have to double the amplifier power, to 160 watts per channel. Electrical power in watts jumps even more if you want a level that is "twice as loud." This occurs because of the logarithmic relationship of electrical watts to actual loudness in decibels (dB). Because of the way an amplifier converts power output in watts into acoustical sound, it takes a big increase in watts—double the amount at the least—to get real increases in maximum volume that we describe as "somewhat louder" or "twice as loud."

Much of the time, your receiver will only need to produce a few watts per channel, typically somewhere between 1 watt and 10 watts per channel, to produce ample levels of loudness. But if you crank it up or a big dynamic peak in a movie soundtrack comes along, the receiver may have to deliver ten times as much power. So that 8 watts per channel suddenly becomes 80 watts per channel! Keep in mind too that about 90% of A/V receivers are rated with only one or two of the front channels driven at full output; the rest are running at a fraction of the main channel's output. For more on the relationship of amplifier power and playback listening levels, click here.

Q. I want to set up a 5.1-channel surround home theater in my media room as well as running sound in several other rooms and on the patio. My budget is about $2,000. How do I accomplish it?

A. It can't be done on a modest budget. Too many enthusiasts become hooked on the notion of wiring the house for sound in every room—and expect to do it with a typical A/V receiver. Wouldn't you rather have really good home theater surround sound in one room, with a big-screen TV, than pedestrian sound in many rooms, the latter provided by middling-quality non-hi-fi in-wall speakers? Whole-house multi-room systems are complicated and expensive, and require the services of an expert custom installer. And it's very difficult to control the sources from other rooms. But for most budgets and consumers, a thrilling home theater surround system in one room for $2,000, plus a High-Def big-screen TV (budget another $2,000 or more, depending on screen size and technology) is a far more realistic goal, and one that will satisfy family members better.

Most AV receivers will let you run one set of speakers on the patio (in addition to your home theater in the living room) but you won't be able to independently control the volume from the patio speakers without going to significant additional cost. If you want multiple rooms, it gets complicated and expensive. If you want different programming going to the patio from what's playing in the living room, that also gets expensive.

You can run multiple speakers on what's called a 70-volt system, but that's way too complicated for consumers and requires an installer and special transformers.

For more tips on inexpensive alternatives to getting sound in other rooms, click here.

Q. The "impedance" of the main speakers I'm considering is rated at 8 ohms, the center channel is 6 ohms, and the two surround speakers are nominally 8 ohms. How do I match the varying impedances to my A/V receiver?

A. You don't have to match the impedances because each speaker in your surround system is driven by its own individual amplifier inside your A/V receiver. Understanding impedance, fortunately, isn't all that complicated. First, and most important: Impedance has nothing to do with sound quality. A 4-ohm speaker isn't "better" than an 8-ohm speaker. With a 5.1- or 7.1-channel A/V receiver, you do NOT have to match impedances of the various speakers in a surround sound system. You can use 8-ohm main speakers on the front left and right channels, a 6-ohm center, and 6-ohm surrounds, or a mixture of the above. The only impedance rating that may cause problems with some brands of A/V receiver is 4 ohms or less, particularly if it's the main speakers that are rated at 4 ohms. A 4-ohm speaker requires more current flow (somewhat like water through a fire hose compared to a garden hose), so the transistors heat up more because more current is rushing through them to get to the speakers. Some brands of A/V receivers don't like this, and will overheat and temporarily shut down. If you like a particular speaker model that happens to have a 4-ohm rating, e.g. the Axiom M80 towers, then email or phone Axiom's toll-free line inquiring as to which brands of A/V receiver we recommend for the M80's. For more on detail on impedance and how it interacts with an amplifier, click here.

Q. I want to upgrade to an HDTV large screen—either a plasma flat panel or one of the new DLP or LCD rear-projectors—but my budget is limited. I've designated $3000 for the big-screen TV and I'll have about $1000 left for a surround system. Please advise.

A. Trust me: Don't blow your home theater budget on a big-screen TV that is too large or too costly, leaving little for a high-quality home theater surround sound system. Once you upgrade to a sharper large-screen TV image, you will want to match the screen image quality with equivalent sound quality, so budget as much for the home theater surround system as you designate for the TV display. Infatuated with the "coolness" factor of flat-panel plasma or LCD panel displays, too many consumers spend thousands on a flat-panel TV, only to find they don't have enough money to assemble a high-quality surround sound system. Disappointment is inevitable. A $399 home-theater-in-a-box will sound pint-sized and out of scale with the impact of the big-screen high-quality video image. And do not ignore picture-tube (CRT) technology that is much less expensive than the latest LCD, DLP, or plasma flat-panel displays. The newest HDTV technologies are expensive, costing twice as much as a CRT-based HDTV rear-projection set. Excellent 46-inch to 50-inch HDTV rear-pro sets based on proven CRT technology are available for under $1,000, about half what a DLP or LCD rear-pro set of the same size sells for. For more on the advantages and disadvantages of different TV display technologies, click here.

Q. I've been told that there are subwoofers and speakers that are good for home theater and others that are great for music. Can you explain which one the Axiom subs are best suited to, and why?

Axiom EP500 subwoofer in custom high-gloss cherry finish

A. A smooth, accurate and transparent loudspeaker or subwoofer doesn't distinguish between different types of sound. It does not know which electrical signals are reaching it from the amplifier, DVD player, CD player or turntable, whether it's the sound of a summer rain storm on a movie soundtrack, an explosion in a war picture, the dynamic musical shadings of a full orchestra, or the full-bore impact of a rock band. The final test of a transparent loudspeaker is always accuracy, and musical realism, and that includes subwoofers. A neutral loudspeaker accurately reproduces the audio signals, no matter what the source, so a subwoofer capable of realistic reproduction of a jazz acoustic bass or pipe organ will do just as good a job with explosions and dinosaur footfalls. Likewise, the delicate timbre of male and female vocals and movie dialog or even the sounds of a helicopter flying overhead will be handled with equal aplomb by an accurate speaker. Read more about excavating deep bass.

Q. I'm upgrading to a big-screen TV display. How do I figure out what size of screen to get? Is there some method to determine the ideal screen measurement?

A.For true HDTV programming presented in 1080i (interlaced) or 720p (progressive scanned) lines, you can view the screen from a distance that is twice the diagonal screen measurement, about 8 or 10 feet back from a 50-inch widescreen set. But keep in mind that most High Definition (HDTV) and Enhanced Definition (EDTV) sets are exhibited by retailers using HDTV or DVD signals, which will look stunning on the new DLP, LCD, plasma or CRT large-screen sets. Don't forget just how crummy conventional analog non-HDTV programs may appear viewed that close. Consider how much standard broadcast material you watch because you will want to be three to four times the diagonal screen measurement back to view it about 12 to 15 feet. While more and more TV series and special events like the Olympics are broadcast in HDTV, there are still hundreds of shows and thousands of hours of TV, including newscasts and lots of older TV series that conform to the 50-year-old NTSC television standard. If you get too large a screen, these conventional TV images can look much worse than on your old 27-inch or 21-inch small-screen CRT set. No amount of special Digital Reality Creation or line-doubling circuits can upgrade poor-quality video, and the larger screen simply magnifies the flaws.

Having lived for a number of months with Samsung's model HLP5063W 50-inch DLP widescreen rear-projection HDTV, I can attest that this set has stunning picture quality. Viewing NBA basketball in HDTV and DVD movies from a viewing distance of 10 feet away, the image clarity is a knockout. But regular broadcasts in 4:3 non-HD look quite fuzzy and degraded on that big 50-incher unless I move back from 12 to 15 feet. Call me a High-Definition snob, but once you've viewed great HDTV programs or DVDs for a few days, you immediately notice all the defects in conventional TV. Everything will be in Hi-Def eventually, but that is still some years away. For more tips on moving to a large-screen HDTV set, click here.

Q. I've noticed that some large-screen rear-projection sets I've checked out in stores look kind of dim and washed out. Is this a problem with all rear-projection TVs?

A. All rear-projection large-screen sets are optimized to display the best contrast and brightness when viewed with the screen at eye level. As you move to one side at increasing angles there will be a distinct fall-off in brightness and contrast, usually at angles greater than 45 degrees from directly in front of the screen. Few stores display rear-projection sets properly, raised on a platform. If you look at the picture quality of a rear-pro set that is on the floor from a standing position, it's not a fair test, as it will be much dimmer and have less vivid color and contrast than when it's viewed correctly. Sit down or squat down to look at the set if you are comparing two different rear-projection models. Look for stores that raise the TVs up on a platform or have a seating area so you can judge picture quality at its best— at eye level. New rear-projections sets are much better at delivering uniformly bright and sharp images over a fairly wide viewing area, but it's still worthwhile to check a set in the store for hot-spotting, an unusually bright spot in the center of the screen. Check the picture for uniform brightness and contrast as you view it at increasing angles away from head-on. For more detail on HDTV and large-screen technology, click here.

Q. Some stores tell me to use direct-radiating speakers at the sides or rear, while others tell me I need a bipole/dipole type of surround speaker. Please explain which type I should get, and why?

A. In virtually every listening situation for DVD movie playback or for multichannel music, quadpolar surrounds like Axiom's QS8 surrounds will be more effective than direct-radiating speakers at producing convincing surround sound involvement for all viewers and listeners. Although conventional direct-radiating speakers can be equally excellent as surrounds if you are sitting in the ideal sweet spot (halfway between the surrounds, and midway between your front speakers), if you move away from that position and for other viewers or listeners in the room the quadpolar surrounds will deliver superior envelopment and involvement in the music or movie experience. And because of their all-directional qualities, they will be much simpler to place in the room without fussy fine-tuning required. For more detail on the specifics of surround placement, click here.

Q. What type and gauge of speaker cable do I require to make sure I don't lose sound quality? I've seen many brands, some of which are very expensive.

A. Don't get caught up in the cable and connector debate, wasting large sums on special cables from manufacturers whose scientifically insupportable claims of improved sound quality have never been demonstrated in controlled double-blind tests.

Using 12-gauge copper speaker cable will be effective even for quite long runs of 40 feet or more to your main and surround speakers. This will keep resistance to a fraction of an ohm, an electrically insignifican't and inaudible—level. Using good quality cable and connectors is prudent, and gold plating will never tarnish, but keep in mind that the electrical contact made by the connector is no different from a bare wire inserted through a binding post. Most manufacturers of specialty cables and connectors simply want your money, hoping that your imagination combined with the high cost, will supply the alleged magical qualities claimed for their special cables at thousands of dollars per pair. For more in-depth discussion on the cable controversy, click here.

1. I have an A/V receiver rated to drive 8-ohm or 6-ohm speakers, but a home theater system I'm considering has a 6-ohm center speaker, 4-ohm main speakers and 6-ohm surrounds. How do I match the impedances?

You do not have to match speaker impedances! A 5.1- or 7.1-channel A/V receiver contains up to seven separate amplifiers, each one assigned to a specific speaker in the system. So each amplifier only sees one impedance per channel, not five or seven. The respective speaker impedances of the other speakers and channels don't need to match. Many A/V receivers will easily drive a pair of 4-ohm front speakers, a 6-ohm center channel, and two pairs of 8-ohm surrounds. Speaker impedance has nothing to do with sound quality. It's an electrical characteristic.

2. My new house came pre-wired for ceiling speakers. Can I use those for my surround speakers?

You can, but you won't get anything like the enveloping surround effects and the precise directional cues originally conceived by the movie director and the film sound designer because the effects channels are intended to go on the side walls, just like in a big cinema. Dolby Digital and dts 5.1-channel movie soundtracks are mixed with the surround speakers to each side of the mixing studio about 2 feet or more above ear level, in order to imitate the enveloping sound field created by surround speakers on the side walls of movie theaters (plus a couple on the back wall behind you). Axiom quadpolar QS8 and QS4 surround speakers use four drivers each to mimic the envelopment created by banks of surround speakers on a movie theater's side walls.

3. My Sony Playstation has a standard RCA video output, but my new TV only has S-Video inputs. If I get an RCA-to-S-Video adaptor, how much improvement can I expect in picture quality from the Playstation?

You'll get little or none. Adaptors that convert a video signal from a composite connector (a single RCA plug, usually coded yellow) to S-Video cannot add detail to the incoming video signal because the signal is already degraded in the source component (your Sony Playstation). Likewise, S-Video-to-Component-Video adaptors are limited to the inherent quality of the original S-Video signal. The adaptors are a convenience, so you don't have to run a variety of different cables, or in your case, to let you feed your Playstation video signal to your new TV's S-Video input. Up-converters or video scalers (by Faroudja, Silicon Optix, Genesis and others) found in some new A/V receivers may add a more filmic look a smoother picture free of scanning lines and video noise—but actual detail cannot be added.

4. I don't want to be bothered with a subwoofer. Can't I get big floorstanding loudspeakers with good bass response instead of a separate subwoofer?

The increased deep bass output from a well-designed floorstanding speaker will usually give you an extra musical octave of bass coverage over that of a small bookshelf speaker, typically extending the bass from about 60 Hz down to the 30- or 35-Hz region, and that's enjoyable and important. But all floorstanding speakers quickly lose output and extension below that frequency. And that's exactly where many of the really powerful movie soundtrack effects begin some go as low as 13 Hz— which is why a subwoofer will bring more impact and clout to a home theater system's low-frequency special effects and music score. There is another downside to using only two front tower speakers without a subwoofer or center channel: Dolby Digital and dts movie soundtracks and multichannel music recordings are mixed with low frequencies dedicated to the subwoofer, and midrange dialog or vocals intended for the center channel. While this material (six channels) will be mixed down by the DVD player for 2-channel playback (if you remember to correctly set the DVD player), you will inevitably lose some of the clarity and extension of deep bass as well as the precise directional cues of center channel information. By contrast, a powerful subwoofer will add much realism to all sorts of music, whether it's the driving bass of a rock band, the percussive impact of orchestral bass drums, or the clout and slam of a great bass solo in a jazz group. It's not just about the lowest frequency, either. A sub is also about sheer power: a large woofer in its own big enclosure powered by a 200-watt amp (or larger) and dedicated only to producing powerful deep bass takes the load off the rest of the system's woofers, thereby reducing distortion and enabling cleaner, louder playback levels. Deepest bass is produced with better precision and slam (impact).

5. Do I have to make all the speaker cables the same length for each speaker in a 5.1-channel or 7.1 surround system?

No. This is another myth perpetrated by retailers to sell you more overpriced speaker cable than you require. Just use the length of cable you need to conveniently reach the speaker from the amplifier or receiver. There are no electrical or acoustic benefits to making all the cables the same length. If you use 12-gauge copper speaker cables, the resistance will be electrically insignificant even with long cable runs of 50 feet or more. Don't underestimate how much you may need, of course. You may have to snake the cable under rugs and behind furniture, so measure the distances beforehand or buy a bulk supply, e.g. 100 feet, cutting off the lengths you need to reach each speaker in the system.

6. What's the big deal about surround sound? For my purposes, I don't see any benefit. My entire 500-CD collection is 2-channel stereo and I hardly ever watch DVDs. Simple stereo is OK by me, so why should I pay for a 5.1 channel surround system?

It may come as a surprise, but hidden in those two stereo channels on many of your CDs is lots of directional information that the original microphones captured but you aren't able to hear in stereo. In the same way that our two ears and a brain interpret sounds from all sorts of directions around us, many 2-channel recordings have what's called out of phase information that the two or more microphones pick up. But those signals are largely ignored in stereo playback. A 5.1-channel home theater surround system will extract and decode the out-of-phase directional cues and ambient sounds and route them to the surround speakers and the center channel reproducing the relative spatial and timing cues. In effect, it reproduces a more realistic soundfield of the original recording. Lots of CDs in your collection may benefit hugely in realism when played back through a modern Dolby Digital, dts, or Logic7 surround decoder. Discs of live pop, rock and concert recordings, jazz, classical works, opera, and plenty of vocal albums will sound much more realistic, with enhanced depth and spaciousness. Not every recording benefits, of course, but a great number do, and there is nothing phony or artificial about the process. The decoders used are called Dolby Pro Logic II (and its latest version DPLIIx), dts Neo:6, or Logic7 (the latter is only offered on H/K and Lexicon equipment). Besides, if you are really married to stereo listening, you can always turn the surround off and listen in stereo. You are not compelled to listen in multichannel surround sound, but you may come to love it!

7. I'm laying out plans for a new house and I want to set up a home theater in a dedicated room in my house or in a family room. How much should I budget for video, audio and other components?

Decide how large a room it will be how many viewers you might want to seat because the larger the room, the bigger the speakers and amplifier/receiver you will need to fill the space with high-accuracy clean sound as well as the larger the big-screen TV display will need to be. Let's take a typical example: a room that's 20 feet long by 14 feet wide with a normal ceiling of 8 feet. The viewers might be seated 12 to 16 feet from the TV display. If you are satisfied with DVD clarity and resolution (480 lines progressive, known as EDTV), excellent front DLP projectors that throw a huge wide-screen image (120 inches diagonal) viewable over a wide area can be had for $1,500. (For front projection, you must have a room that can be made completely dark for the best image clarity.) True High-Definition image clarity (HDTV) from a front DLP or LCD projector costs more—$3,000 and up. Allot from $2,200 to $3,500 for the HD display (a 50-inch diagonal DLP or LCD rear-projection HDTV), about $2200 for the surround speaker system (the latter based on an Axiom Epic 60/350 5.1-channel speaker system) and perhaps $600 to $900 for the A/V receiver. A budget system in a smaller room (2,100 cu. ft or less) might typically cost $1600 for the surround speaker system, $1500 or less for the HDTV (a CRT rear-projection or direct-view set), and $350 or more for the A/V receiver. A progressive-scan DVD/CD player is about $80 to $150. Axiom's archives are filled with details on setting up rooms.

8. I'm not technically adept, so setting up a simple stereo system can be challenging. How can I cope with the intricacies of a 5.1-channel surround system?

Most A/V surround receivers have factory settings that you can access or default to if you're confused. Those will get you up and running in 5.1 channels with the subwoofer, and you can refine the relative balance of each channel as you become more familiar with the receiver, its menu and its remote control. Many new A/V surround receivers are including automatic setup systems that calculate speaker size, speaker distances, delay times and the correct loudness levels for each channel. While great in theory, some of the auto setups may be problematic, especially if they attempt room equalization and/or phase settings. However, each year brings new surround receivers that are easier to use with more accurate auto-setup modes and they are often less expensive than earlier models. Personal on-line help is also available from some companies (Axiom).

9. Which type of High-Definition TV is best? There seem to be so many new technologies to choose from.

What do you want from a new TV display? Do you want to watch it in a darkened room on a really big screen that simulates a real movie theater presentation? If so, look at an LCD or DLP HD front projector they are compact and relatively affordable ($3000 and up for true HD; $1500 or less for EDTV DVD resolution). You would also need a separate screen, which will add to the cost. Or would you rather watch in a lighted family room? If the latter, then look at a flat-panel plasma if you want the screen 42 inches or larger. Plasmas will deliver an extremely bright image, viewable over wide angles in a brightly lit room. In HD versions, they are expensive, about $3,500 and up. If you'd like a smaller screen, under 42 inches diagonal, then LCD is the way to go. They are also quite bright, less expensive than plasma, and viewable over quite wide angles. Neither of these technologies produce quite as much contrast and deep blacks as you can get from a DLP rear-projection set, but you won't get a DLP in a flat panel. They occupy more space the thinnest are typically about 14 inches deep. Nevertheless, these are capable of excellent HD performance and currently are much less costly (in equivalent screen sizes) than plasma or LCD panels. DLPs in 46-inch diagonal screen sizes start at $1800, moving to $3100 for a 61-inch diagonal. The best LCD rear-projection sets are also very close to DLP, if not quite the equal in contrast and deep blacks. At a budget level, if you can accommodate the bulk (from 24 to 30 inches deep) and weight (200+ pounds) of CRT (tube) direct-view or rear-projection sets, those start at $1,000 and are capable of excellent picture quality.

But lack of precision can be equally annoying. Sometimes, for instance, a vague statement about positioning Axiom QS8 or QS4 multipolar surrounds just isn't enough—“Oh, place them on the side walls above your ear level, and slightly to the rear of the listening area. . .” is just too unclear. So, for all those newcomers to 5.1, 6.1 and 7.1 home theater setups, as well as seasoned enthusiasts who want precise directions, here they are, courtesy of Dolby Labs, the developers of Dolby Digital and its many variations.

As you are reviewing the diagrams, remember that the goal of all speaker placement for movie soundtrack playback and multichannel music reproduction—even stereo—is a smooth, consistent and unbroken soundstage across the front, coupled with a sense of envelopment in the ambient surround effects. In other words, you're after a sense of location, whether that is suggested by what's on-screen, by the recording venue or even the dry, intimate acoustic of many pop/rock studio recordings.

As you experiment with speaker locations, think back on a really great Dolby Digital movie presentation in a big cinema when you had a good seat in the central part of the auditorium. You are not constantly looking up at the surround speakers on the side walls or at the back of the theater. The same applies to a home installation. You don't want to “hear” the location of specific surround speakers or, for that matter, your main left and right front speakers. Involvement in the movie or music (whether multichannel or not), is everything . That is the goal. If a sound is “hard-mixed” on a recording or soundtrack to a particular spot at the side or rear, then it's OK for it to appear there (I'm thinking of an Aaron Neville multichannel recording where the backup chorus is hard-mixed to the right surround. . .which seems a bit odd, but you get used to it. Maybe the backup singers were in that spot in the studio.). In Dolby Digital 5.1 soundtracks, most movie dialog is hard-mixed to the center channel, and if you experiment with center speaker placement, the dialog should be one with the actors on the screen. It shouldn't seem detached from the screen. If it is, you have your center channel too far away from the screen.

Fig 3. Suggested Corner Arrangement of Dolby Digital 5.1 Channel Setup

For multipolar surrounds or direct-radiating speakers used as surround speakers, the same angles and placement suggestions apply. A few receivers have facilities for using two different types of surrounds (multipolar and direct-firing) and if you have that luxury, great. Likewise, there are some Axiom customers who have gone with floorstanding speakers—e.g. five M80ti's—all round. Although SACD or DVD-Audio recordings are mixed using direct-radiating speakers all around, Axiom's double-blind tests have shown that Quadpolar QS8 surrounds deliver a more generous listening area at different locations in the room. If you are in the "sweet spot," our double-blind tests also showed that listeners weren't able to discern any significant differences in multi-polar or direct-radiating surrounds with SACD or DVD Audio.

Subwoofers

Since deep bass 80 Hz and below is non-directional, the subwoofer can go just about anywhere on the floor, but corners will give you the greatest enhancement of deep bass, at the risk of it sounding boomy. Moving a subwoofer or a floorstanding full-range speaker away from any intersecting room boundary will reduce the tendency to boom or to have too much bass. In either case, you will have to experiment to achieve smooth and extended deep bass in your preferred listening location. Bass output will vary in different spots in the room as a function of the room's dimensions, so aim for good bass extension in preferred seating locations. You can't satisfy everyone in the room, although adding a second subwoofer will help smooth out the bass for other listening locations. Look in the A/V Tips and Axiom Digital Library for more detail on subwoofer placement tricks.

Likewise, the worldwide acceptance and market success of the Compact Disc (and before it, the LP record) underline the ongoing failure of SACD and DVD-Audio (the two high-resolution multichannel audio disc formats) to attract widespread consumer interest and sales. In fact, more vinyl LP albums are currently sold than DVD-Audio or SACD discs combined, a somewhat startling statistic!

Incompatibility Spells Failure for SACD and DVD-Audio

The failure of SACD and DVD-Audio to achieve any kind of market presence can be blamed on their incompatibility with each other and with most existing DVD players. While there are a few "Universal" DVD players available (some costly, some inexpensive) that play both DVD-Audio and SACD discs, it's too late to capture any kind of mass acceptance. The momentum was lost early on when the Sony SACD camp (Philips and a few others) and the Matsushita DVD-Audio group (Panasonic and many others) refused to combine the best qualities of each format in a compatible format that would prove attractive to a mass audience.

HD-DVD and Blu-ray

Unfortunately, a similar scenario is brewing with the launch this year of two incompatible High-Definition DVD standards. Consumers will either keep their money in their pockets and wait until market forces determine a winner or jump onto the first player out of the gate, which happens to be Toshiba. There are now two high-definition disc formats vying to replace the DVD: Blu-ray and HD-DVD. And just like SACD and DVD-Audio, each format is incompatible with each other. The only slight assurance for consumers is that at least Blu-ray and HD DVD will be backwards compatible with existing DVDs, which means that no matter which high-def disc format wins out, you'll still be able to play your existing DVD collection (with standard DVD quality) on a new high-definition DVD player. (But you wouldn't be able to play an HD-DVD or Blu-ray disc in your current DVD player.) So, yes, if you wanted to benefit from HD video quality on a disc, you'd have to make a choice between either the HD-DVD format (Toshiba) or the Blu-ray, backed by Pioneer, Sony, JVC, Samsung, Panasonic, LG, and Philips. (By the way, Thomson/RCA, Hewlett Packard and Microsoft are hedging their bets and backing both HD-DVD and Blu-ray formats.)

HD-DVD's chances of commercial success seem slim, except for one important fact: Toshiba's HD-A1 HD-DVD player will be available in March '06 and retail at $499, less than half the price of Blu-ray machines, which won't be available until summer and will sell for $1,000 to $1,800. On the other hand, Blu-ray has lots of movie studio backing, including Lion's Gate, MGM, Columbia, Fox and Disney, with releases like Pirates of the Caribbean, Kill Bill, and House of Flying Daggers promised as early as this summer.

Blu-ray's and HD DVD's Capabilities

In many respects both HD formats have highly similar qualifications. Blu-ray and HD DVD both use new short-wavelength blue lasers, which will focus on and read much tinier pits than the larger red lasers used in your current DVD player. (The pits plus the "land"-the spaces between the pits-represent the digital code or pulses that carry the video and audio data.) When you want to record ultra-sharp full-motion HD video images, it takes far more data to encode the video and audio, a huge amount in fact. What that means is that normally you'd have to make the disc much larger to hold all the HD video content. If you don't make the disc larger then you have to make the pits much smaller, and cram more spirals of pits much closer together onto a disc. Smaller pits require a laser that can read the tiny pits, so both Blu-ray and HD DVD chose a blue laser. But the Blu-ray disc's pits are even smaller than those used on HD DVD, so Blu-ray's storage capacity is greater than HD DVD's.

A single-layer Blu-ray disc will hold 25 gigabytes (GB) with a dual-layer disc carrying 50 GB. By contrast, HD DVD has a maximum of 15 GB (single layer) and 30 GB (dual layer). (Both Blu-ray and HD DVD will also have single- and dual-layer rewritable discs, with storage capabilities similar to their read-only versions.) You can argue that greater capacity is always more attractive, but keep in mind that both of these HD disc formats have relatively huge capacities, especially Blu-ray's at 25 GB for a single-sided single-layer and 50 GB for a single-sided dual-layer disc, or roughly 5 hours of HD material. These capacities carry through to the recordable (write-once) and rewritable (erasable) versions as well. TDK has already developed a quad-layer 100-GB Blu-ray disc capable of storing ten hours of HD material.

To achieve that enormous capacity, Blu-ray's pits are not only tinier but also the disc's recording layer is much closer to the disc surface. Although HD-DVD's potential capacity is significantly less than Blu-ray's staggering 50 GB capability, HD-DVD has one large advantage. Replicators (the manufacturers of the actual high-def discs) can economically put HD DVDs into production with only minor modifications to existing DVD pressing machinery. Blu-ray, on the other hand, requires totally new retooling, plus new manufacturing lines and presses, so there is a huge potential capital expense for Blu-ray disc manufacturers.

HD DVD also has one other advantage over Blu-ray. A hybrid HD DVD is possible, with a regular DVD movie version on one side of the disc and the High-Def version on the flip side, a feature that retailers and consumers would applaud.

Toshiba's HD-DVD player will be backwards-compatible and so will the Blu-Ray machines, which means they will play your existing DVDs with ordinary DVD resolution (480i; 480p) as well as new High Definition discs. Statements by various spokespersons suggest that HD-DVD is 1080p capable, but the HD-DVD machines I've seen output 1080i via HDMI outputs. Blu-ray players are definitely 1080p compatible.

HD DVD and Blu-ray's Much Improved Audio Capabilities

It's hard to fault any of the HD disc formats' stupendous audio capabilities, which include lossless multichannel audio for eight discrete, full-frequency channels from both Dolby and dts. Dolby Digital Plus, which is a "lossy" algorithm like Dolby Digital 5.1, will be the core audio format, with capabilities of up to 13.1 discrete channels but in most applications running at 7.1-channels, all discrete. Dolby Digital Plus will run at its highest rate of 640 kilobytes per second (kbps) rather than 448 kbps (the current highest data rate of Dolby Digital 5.1), and will be backwards compatible with your existing Dolby Digital/dts AV receiver, only to the extent that embedded in the data stream will be a standard Dolby Digital 5.1 mix. If your existing AV receiver has a Dolby Digital decoder, then it will process a Dolby Digital 5.1 mix from an HD-DVD or Blu-Ray player.

But Dolby also has TrueHD, based on Meridian Lossless Packing developed for high-res DVD-Audio discs, which enables eight full-frequency channels that are totally lossless (a "lossless" audio record/playback format delivers audio that is bit-for-bit identical to the studio master recording). Dolby TrueHD will be mandatory in HD-DVD players and optional for Blu-ray players. Dolby TrueHd runs at data rates of 1.6 Mbps to 3.6 Mbps and will support 16-to- 24-bit word lengths as well as sampling frequencies of 48 to 192 kHz. To get TrueHD, you'd need an HD-DVD or Blu-ray player with built-in decoders for the high-resolution audio (the Toshiba players have those built in) as well as an analog 8-channel input on your AV receiver. Alternatively, Dolby TrueHD will also output an 8-channel PCM data stream via HDMI or IEEE 1394 "Firewire" connectors. But that would still require a TrueHD decoder to sort out channel ID's and the like. Dolby Labs intends that all audio processing for TrueHD be done in the HD-DVD player, not in the A/V receiver.

DTS will also be a standard soundtrack of the new HD disc formats, and your existing dts AV receiver will decode the dts soundtrack, possibly running at higher data rates, which should mean better sound than you hear now from dts. Like Dolby's TrueHD, dts will also have its own lossless format, called dts HD, and as with Dolby TrueHD, you'd need to have an HD player with a built-in dts-HD decoder to benefit from dts HD's lossless capabilities. If your current A/V receiver has an 8-channel analog input set, then you'd be able to enjoy the improved audio capabilities of DVD-HD and Blu-ray players by connecting the eight analog audio outputs from the HD player to your set of analog inputs on the AV receiver.

If we sit far enough away from the TV screen, the individual clusters of colored dots blend together to form a smooth and coherent color picture that changes 30 times every second. Our eyes and brain blend the rapidly changing still images into continuous and smooth action, through a process called “persistence of vision.”

Lines and Lines The 60-year-old analog TV system all of us grew up watching is based on 525 horizontal scanning lines, although only 480 lines are actually used to scan the picture from top to bottom across the TV screen every 1/30 of a second. A single frame of TV is composed of two “fields” of 240 lines each, presented every 1/60 of a second, which are “ interlaced ” or interwoven to form a full picture every 1/30 second. This happens so quickly that our eyes blend the 60 still fields together into 30 frames (each frame is a still picture) and we see only continuous motion.

Definition: Standard and High Because the image is composed of 480 interlaced lines, the system is called 480i, and is known as standard definition in the world of digital TV. A DVD image represents standard definition. The number of scanning lines determines the amount of detail in the image (vertical detail, because the horizontal lines are stacked from the top to the bottom of the screen). Understanding this process will help you understand the differences in clarity or resolution (sharpness) between regular analog TV and digital TV, including High Definition TV (HDTV). Incidentally, just because a new TV is “digital” does NOT mean it is HDTV. Although all HDTV pictures are digital, not all digital TV is high-definition, because the North American Digital TV standard, established in 1995 by the Advanced Television Systems Committee (ATSC), enables 18 different formats and various levels of clarity— Standard Definition , Enhanced Definition (EDTV), and High Definition (HDTV).

If you get a digital TV, a DVD's 480-line image can also be progressively scanned, one line after the other in sequence, rather than interlaced. This is called 480p, and represents Enhanced Definition (EDTV). A 480p TV image has a smoother, more film-like look, especially when it's viewed on a larger screen, but a digital TV set is usually required to display progressive-scan (480p) pictures (most analog sets will not, except for a few equipped with component-video inputs that are designed to handle progressive-scan signals.) Almost all newer DVD players on the market, even inexpensive ones, will output both interlaced and progressive-scan signals, so if you are getting a new DVD player, make sure it has progressive-scan outputs as well as interlaced (you must switch your DVD player to the interlaced output to see a DVD picture on your old analog set.)

Wide or Square A standard definition picture can be viewed in the familiar 4:3 (almost square) format or in a widescreen 16:9 aspect ratio (the width-to-height ratio of the screen). You may have noticed the different screen shape of most new digital TVs. The clearly rectangular 16:9 screen is the standard for digital TV, and more closely approximates the theatrical screen shape of most movies made since the late 1950s, when widescreen film processes like Cinemascope and Panavision became popular. (Sony, Panasonic and a few other major brands still offer some new digital HDTV-ready sets in the boxier 4:3 screen shape, but eventually all new digital sets will be widescreen.) All high-definition programming allowed by the ATSC hi-def standards is widescreen as well.

Details, Details By adding more scanning lines from top to bottom, either interlaced or progressive, more detail results in the picture. Some of the US networks (CBS and NBC) broadcast HDTV with 1080 interlaced lines (1080i); ABC uses 720p or progressively scanned lines. A digital TV must, by law, be able to display any of these transmission standards, including 480p and 480i, but you may get only standard definition clarity. Many digital TVs are not capable of displaying full 1080i or 720p HD signals, particularly the least-expensive flat-panel LCD and plasma sets. These sets may only work at 480p and will convert or “scale” any incoming signal to 480p—still much clearer than analog TV, but not as dramatically improved as a digital set that will display the full HD 720p or 1080i scan rates.

We've talked about vertical detail determined by the number of scanning lines, but there is also horizontal information in a TV image. The number of dots or pixels across the screen will determine the horizontal detail of a standard or high-definition image. Standard definition may have 704 pixels across the screen. A 1080i HDTV image can have 1920 pixels while a 720p HD image may have 1280 pixels. Don't get bogged down in the number of pixels! An HDTV picture in 1080i looks roughly as pleasing and clear as one in 720p. Progressive scanning produces a smoother, more film-like look, but a 1080i image actually contains greater detail. Each is sometimes better suited to different subject matter. Though it has fewer lines, the native progressive scan format (720p) eliminates motion artifacts that originate in interlacing, and are still visible in 1080i viewed on a large screen. For subject matter that contains a lot of rapid motion—Monday Night Football, basketball or hockey games, for example—720p will produce a clearer, more stable picture than 1080i. Alternatively, for subject matter that has very little motion, 1080i is capable of rendering more picture detail. Both, however, can be visually stunning, up to five times as clear as your old analog TV picture.

Nevertheless, with HDTV programs in either 1080i or 720p, you'll see individual blades of grass, the makeup on actors' faces, even the scratches on a news anchor's desk. But the beauty and wonder of high-definition images have an almost hypnotic effect, even after repeated viewings. Nature documentaries are like being there. (Don't even discuss VHS and VCR images, which at best produce about 240 lines of resolution. That's why VHS videotapes always look somewhat “soft” and out of focus, even compared to conventional analog TV broadcasts.) In terms of clarity and detail, HDTV is to conventional analog TV like DVD is to VHS videotape, as big an advance in TV as the switch from black and white to color broadcasting 50 years ago.

And the Sound? The audio standard for all SD, ED and HDTV digital programming is Dolby Digital, which means it's a digital audio signal of at least two channels and in many cases, six (Dolby Digital 5.1 surround). It seems logical once you've upgraded the video image to high definition, to match the video with an upgraded audio experience: a home theater surround system capable of comparable fidelity and clarity.

Another less talked-about benefit of digital TV is the absence of noise or visible “grain” that you see in non-digital analog TV images; it's also why DVDs can still look remarkably beautiful even on an aging analog set. (The downside of digital TV is that it very occasionally may “pixelate,” or freeze with weak or intermittent digital signals or if there is a glitch in a DVD player's output or physical damage to the DVD surface.)

No matter what signals you feed into a digital TV, interlaced or progressive-scanned, the digital TV will “up-convert” or “line-double” the signal so it can be displayed. That doesn't mean that videotapes from your old VCR, laserdiscs or conventional broadcast TV programs will have high-definition detail and freedom from noise. Depending on how effectively the conversion is done by the set, some of those signals may look better or a lot worse when they are enlarged and line-doubled, so don't sit too close to a large-screen HDTV if you are watching old videotapes, laserdiscs or non hi-def TV programming. But with 480p DVDs, 720p and 1080i HDTV broadcasts, you may indeed sit much closer to the screen than you would with old programming on an analog set. A very rough rule for viewing distance is to double the diagonal screen size for HDTV or DVDs on an HD set, and triple the diagonal screen size if you are viewing non-HD signals or conventional analog broadcasts. That applies equally to direct-view, flat-panel and rear-projection TVs.

Receiving HDTV Speaking of video signals, how do you receive HDTV broadcasts? The three most common methods are via satellite-TV set-top box, a cable system set-top box, and over-the-air (terrestrial) reception from a digital HDTV broadcast station. Most digital HDTV and EDTV sets are “monitors,” lacking an internal HDTV tuner for terrestrial reception by antenna. If that's what you want and you are within range of an HDTV station, then you must buy an outboard HDTV tuner that connects to your monitor or one of the “integrated” HDTV sets that contains its own digital HDTV tuner. But if you prefer satellite TV or cable reception, you don't need the extra outboard HDTV tuner because the satellite tuner or cable set-top box performs that function for you. You must make certain you specify an HDTV-ready satellite or cable set-top box, however. All progressive-scanned HD, ED, and SD images are connected through component video cables; some satellite and cable set-top boxes also have new DVI (Digital Video Interface) connectors, which conduct the digital HD signals directly to the set. An even newer type of digital video connector—smaller than DVI, more like an overgrown USB jack—is HDMI (High Definition Media Interface). It carries Dolby Digital sound as well as digital video, and is beginning to appear on new HDTV sets this summer. Adaptors from DVI to HDMI or vice-versa are already available.

Lots of Time Consumers are moving to HD-ready large-screen sets and projectors in unprecedented numbers, almost as fast as DVD players replaced the VCR and videotape. Large-screen rear-projection TVs and direct-view HD-ready sets and flat-panel displays are the fastest-growing sales category in electronics stores and chains. The transition to full digital HDTV throughout North America likely won't be complete until 2010 or so, so you still have plenty of time to chew over which type and how big an HD display to buy, as well as whether you want to stick with the familiar old 4:3 screen shape or go for the widescreen 16:9 sets. In a future article, I'll explain the differences and trade-offs inherent in different TV display technologies—CRT, DLP, LCD, rear and front projection, plasma and LCD flat panels. If you can't wait, you can read my brief overview here.

In last month's Axiom AudioFile newsletter feature "Secrets of Amplifier and Speaker Power Requirements Revealed" (August '03), we concluded that using a pair of M80ti speakers at a distance of 12 feet in an average room, and attempting to reproduce the 109-dB peak sound pressure levels of a grand piano playing crescendos, would require an amplifier capable of at least 200 watts per channel output to handle the musical peaks. This would exceed the power output capabilities of most current A/V receivers.

This month, our discussion of amplifier dynamic headroom will assume you have read and absorbed the basics of last month's feature. (Cliff notes on the side if you're just joining us).

To better understand amplifier dynamic headroom, we need to look at dynamic range, and how we experience it in everyday life. On a hike in the woods, most of us know the soft rustling sound of leaves in a tree produced by a gentle breeze, a sound that measures perhaps 20 dB Sound Pressure Level (SPL) at most. And at one time or another we've experienced the sound of an orchestra or brass band in a concert hall at 100 dB SPL (or more), or of an amplified rock band at 120 dB (the latter is the maximum SPL permitted by law in a performance in a public venue). Those levels represent the extremes in dynamics that our ears can routinely register. If we were suddenly transported from that idyllic spot in the woods (20 dB SPL) to the rock concert (120 dB SPL), our ears would register a dynamic range of 100 dB.

Recall that 1 decibel (dB) represents the smallest detectable change in loudness, and that we subjectively perceive a 6-to-10-dB increase in loudness as sounding "twice as loud." What is remarkable, then, is the range in loudness that our sense of hearing can encompass without pain. In fact, our ears can accept even higher levels—a jet engine at 75 feet away measures about 140 dB SPL—before the threshold of pain is reached, but for the purposes of reproducing music or movies at home, let's confine our discussion to the dynamics of musical sounds.

To give you some perspective on music playback in the home, "quiet" music would fall in the 75-dB range, whereas "quite loud" music would measure about 85 dB SPL at your favorite spot on the couch. For purposes of illustration, let's go back to our example of listening to a recording of a solo concert-grand piano of Chopin piano works at average levels of 76 to 86 dB, using a pair of M80ti loudspeakers at a distance of 12 feet. According to our previous calculations, this would require perhaps 1 watt per channel of amplifier power, a modest demand for even the least expensive A/V receiver or small amplifier. If the pianist on the CD was playing Chopin's Grand Polonaise, however, and one of those spectacular chords in the bass octaves of the piano comes along, your amplifier and speakers will suddenly have to produce levels of 96 or 100 dB SPL without distorting, because Chopin's piano works have sudden and extreme changes in musical dynamics. Remember that a 10-dB increase in subjective loudness ("twice as loud") demands ten times as much power, or in our example, 10 watts, a level any receiver or amp will easily produce.

But if it were a real-life orchestra playing at full tilt, and you wanted to reproduce the illusion in your living room of standing next to that grand piano, then peaks of 109 dB would be required. So getting from 96 dB to 106 dB will require ten times as much power again (10 x 10) or 100 watts per channel. The goal, remember, is real-life reproduction of that grand piano, so now we only need 3 dB more (subjectively "somewhat louder") to hit 109 dB in the living room. But twice as much power is required for a 3-dB increase (100 watts x 2 = 200 watts). All of a sudden our A/V receiver or amplifier has run out of power!

Of course, it's just a brief peak, lasting perhaps 200 milliseconds (one-fifth of a second), but the amplifier must have sufficient reserves of power to properly reproduce that momentary peak without distorting. If the amplifier has 3 dB of dynamic headroom, it will make it, and output the required 200 watts per channel for a fraction of a second, with no clipping and no distortion. But the truth is that most A/V receiver amplifiers have little or no dynamic headroom, so the receiver runs out of power, the distortion rises, and audible distortion intrudes, ever-so-briefly. The piano then "sounds too loud," to our ears because of the nasty distortion components, so we turn down the volume just short of our goal, because our amp didn't have enough dynamic headroom to handle the instantaneous peak power requirement.

If your speakers are 3 dB less sensitive than the M80ti's, or you are another three feet back, then twice as much power (400 watts) again would be needed to hit that goal of 109 dB SPL. It doesn't tax our arithmetic skills to realize that aiming for rock concert peak sound levels of 115 dB (if the neighbors could stand it), is beyond our capabilities. Most of our amplifiers and receivers do not have enough dynamic headroom to deliver this kind of power output without sounding strained. (To finish the example, using M80ti's to reach 115 dB at 12 feet would require 6 dB more output, or four times the power that the 109-dB level required, so 800 watts per channel would be needed.)

How do we get that dynamic headroom into our amplifier? To answer that, we need to look at power, and how an amplifier outputs power in watts. Power in watts is the product of voltage, and current, flowing into a resistance (the loudspeaker). Voltage is the driving force, like water pressure in a hose, and it works with current, which is analogous to the rate of water flow. If the hose has greater diameter—or the speaker has less resistance to the flow of electricity, in which case it would be 4 ohms or less, rather than 8 ohms—then the amplifier voltage pushes more current through the output transistors and produces more "power." (We assume the intervening speaker cables have insignificant resistance of less than 0.3 ohms, easily achievable by using 12-gauge cables.) In many respects, it's easier to design an amplifier with big reserves of dynamic headroom to drive 4-ohm speakers, because the voice coils have fewer windings, hence less resistance to the flow of current. With 8-ohm speakers, you are wasting more potentially usable power in heat.

Nevertheless, that power has to come from someplace, and in amplifiers it's supplied by the transformer (which connects to your wall outlet) and by capacitors, which store up the reserve electrical energy from the transformer in "joules." According to Axiom electronics R&D engineer Tom Cumberland, the source of good dynamic headroom in an amplifier "comes from having a transformer with a high-flux core that measures up to 13,000 gauss—if it's any greater, the transformer will buzz—but the higher the flux in the core, the more efficient the transformer is. That will give you lots of sustained current and instantaneous current, which is then dumped into the power-supply capacitors. So the better the transformer and the better and larger the power-supply capacitors, then the better the dynamic headroom is.

"The problem with many amplifiers and A/V receivers designed for economy (the most watts for the dollar) is that they make the transformer just big enough to produce the voltage output they need [to meet sustained power output measurements into an 8-ohm load], and just big enough capacitors to supply the sustained, continuous voltage and current they need for continuous power, and then the amplifiers quit, so those amplifiers have no real headroom. On top of this, the power may be calculated to be the rated output for one channel at full power and the other five at 1/8 power. So a 100-watt six-channel A/V receiver actually only has 162.5 watts of total power or 27 watts per channel with all channels driven. The better amp builders, who design for performance (reproductive accuracy for the dollar) rather than economy, will install these big transformers with huge capacitors, so then they have all these joules of energy in reserve to produce the dynamics necessary for the music."

Another important factor in dynamic headroom is that the output transistors must be very tough, and there have to be enough of them, to handle these instantaneous high-current conditions, because a great deal of heat is generated very quickly. If the transistors aren't of sufficient quality, they'll be pushed outside of the "SOA" (safe operating area) and fail. And that may happen because there isn't enough heat-sinking to keep the output devices cool under these very dynamic conditions.

One hugely important factor we've ignored so far in this discussion is whether the speakers (and the individual drivers) receiving these 200-watt or 400-watt instantaneous bursts of power from an amplifier capable of 3 dB or more of dynamic headroom can handle the peaks without significant distortion. We already know that the M80ti's are tested up to 1,200 watts of input power, but many speakers when confronted with spikes of power input may suffer something called "dynamic compression." What happens is that the sudden peak of input power pushes the driver voice coil beyond the region of magnetic flux, so the voice coil—essentially the "motor" of a loudspeaker driver—loses energy and becomes non-linear. This means it stops producing greater output levels, it can't track the incoming signal accurately, and even the driver's frequency response changes.

(Author's note: During years of participating in double-blind testing of speakers at Canada's National Research Council and publishing the results in Sound&Vision Canada magazine, which I edited, Dr. Floyd Toole introduced a special curve on our charts called a dynamic compression curve, which illustrated the change in a speaker's frequency response under very high power input levels. Unfortunately, it was not well understood by readers, so I stopped publishing the compression curve, but the phenomenon exists with all speakers at some level.)

Fortunately for Axiom, our speakers have fairly prodigious peak power-handling capabilities with little or no dynamic compression exhibited, but while the 140-dB maximum peak levels may remain elusive, it is possible using amplifiers with sufficient dynamic headroom to achieve highly realistic peak dynamics in a living room. The limitation is not in the software. As most readers know, even the two-channel 16-bit CD has a practical dynamic range of a bit less than 96 dB, and the newer formats—DVD-Audio and SACD—have spectacular dynamics. A 24-bit recording has 6 dB of dynamic range for each bit, so the potential dynamic range of these recordings is 144 dB (24 bits x 6 dB), more than enough to contain the dynamics of any known musical instruments or instrumental groups. And our home theater multichannel processors, Dolby Digital 5.1 and dts, have dynamic-range capabilities similar to the CD format. In future issues of the AudioFile we'll look at the history and use of dynamic compression in studio and live recordings, and how in some ways those practices that were so common and necessary in the era of the vinyl LP and analog tape recording have persisted and may account for losses of fidelity in modern digital recordings.

The real challenge that lies ahead is to design amplifiers and receivers capable of delivering huge instantaneous peak power output without distortion. Only then will our reproduced music and movie soundtracks not sound "too loud," and we'll sink back and revel in the thrilling dynamics that we've all experienced at one time or another with live music.

For example, some audiophiles grumbled about the 44.1-kHz CD sampling frequency, which limits its high-frequency response to 22 kHz (the assumption being that we humans can hear beyond 22 kHz, a dubious claim at best and not supported by any scientific data). Others complained that the CD's 16-bit digital "words" (which yield 6 dB of dynamic range for each bit, for a total of 96 dB), don't capture the dynamic range of human hearing, which can extend to 130 dB or higher.

Consumer electronics is nothing if not a history of overcoming technical challenges, so the digital engineers got busy and emerged from their respective camps with two new multichannel formats: DVD-Audio and Super Audio CD (SACD), each of which boasts technical standards beyond reproach. DVD-Audio lets recording producers choose any of several sampling rates and word sizes: 44.1, 48, 88.2, 96, 176.4 or 192 kHz, coupled with 16-, 20- or 24-bit words. By using Meridian Lossless Packing (MLP), a "lossless" compression algorithm that does not discard data (it's like zipping a PC file or stuffing a Mac file), all DVD-A's can deliver six full-bandwidth audio channels sampled at 96 kHz with 24-bit words. Do the math and you'll find that yields an upper frequency limit of 48 kHz (high enough for your family dog or cat or a bat), and a dynamic range of 144 dB (24 x 6 dB = 144 dB).

But (and this is a big "but"), can you play it on your CD player? Nope, you cannot. It will only play on a new DVD player that has a DVD-Audio decoder. And because there are currently 500 million CD players worldwide, that may be a huge impediment to the success of DVD-Audio. However, the good news is that virtually all DVD-Audio discs carry a duplicate Dolby Digital 5.1-channel mix, which means that DVD-A's will play on any DVD player. This will let you sample multichannel music through your existing DVD player and Dolby Digital/dts A/V receiver, but only in Dolby Digital. You won't benefit from the "lossless" 96-kHz sampling rates and 24-bit word lengths that DVD-Audio delivers. To get those benefits, you'd need a "Universal" DVD player that will play regular DVDs as well as DVD-Audio discs and SACD discs.

What about Sony's Super Audio CD (SACD)? Launched by Sony and Philips in 1999, SACD uses Direct Stream Digital (DSD), a 1-bit system with a sampling rate of 2.8 million times a second, about 64 times the sampling rate of conventional CDs. This 2.8-MHz rate yields a frequency response of 1 Hz to 100 kHz, far beyond the response limits of human hearing, and a 120-dB dynamic range that is roughly equivalent to our ears' dynamic range. SACD is now capable of delivering six full-bandwidth DSD channels that encompass those extraordinary standards.

But can you play SACD on a CD player? Yes--and no. An SACD isn't playable on a standard CD player unless it's a hybrid two-layer disc with a CD-compatible second layer. And then you'll only hear it in stereo with CD standards. Oddly, most of Sony Music's own SACD releases are not hybrid discs, and will play only in an SACD machine. But some other labels are now releasing hybrid SACDs, and many of those do take advantage of SACD's multichannel capabilities.

As to how the two formats sound, both are superb. Based on my listening tests, neither format has "better" sound than the other. Do they sound better than CD sound or Dolby Digital 5.1? So far, in my judgment the differences are a matter of nuances. It's not dramatic. Of course, when the musical multichannel mix of an album is done with restraint and invention, the multiple channels can be a huge enhancement, as anyone experienced with Dolby Digital 5.1 can attest. I've left the philosophical/musical controversy of whether listeners want to feel in the middle of a band, with instruments mixed to the sides and rear, or prefer the perspective of the band and performers in front, for another time.

So far, after a number of years on the market, neither SACD or DVD-Audio has been a commercial success. At best, they are "niche" formats, with a limited selection of artists and discs. They are also difficult to find in many retail record stores but you can find them on-line. If you want to sample both audio formats, Pioneer and Samsung have budget Universal models ($175) and Denon has expensive ones ($600) that play both formats as well as conventional DVDs.

If you'd like a taste of one of the new multichannel audio discs, try the SACD "New Favorite," from Alison Kraus & Union Station (Rounder), which mixes the dobro guitar in front and rear channels with Kraus's vocals in all three front channels. A definite DVD-Audio winner is Buena Vista Social Club (World Circuit/Nonesuch), which has an expansive mix with the musicians surrounding the listener. And to get an idea of what an older album remixed for a new format (in this case, DVD-A), check out Neil Young's "Harvest," which also places the musicians around the listener, with reflections from surrounding hills included as ambience on the electric cuts, which were originally recorded in a barn.

We're talking musical bass here, electric and acoustic--deep, low, and powerful, the low-frequency foundation that gives most music its rhythmic drive and pulls us into its ongoing momentum.

Bass is Primal

Bass is innate, and primal, and seems to be almost part of our soul (soul music?) so getting it right is as important to the enjoyment of home theater as it is to just plain music, whether you listen in 5.1 channels, 6.1 channels or in two stereo channels. Without good bass, music sounds anemic and undernourished, robbed of its very foundations.

Axiom speakers, certainly the big ones (M80's, M60's) pump out bass in fairly large quantities in average rooms, and even the modest speakers, like the M3ti and M22ti, do a creditable job on lots of music. But when you head for the home theater or you want to fill a bigger room, especially with dinosaur-type footfalls or the convincing war effects of movies like "Saving Private Ryan" or "Black Hawk Down," most of us opt for a subwoofer. The sub handles all the serious low bass, letting your main speakers (and center and surround speakers) do their best job with upper bass and the midrange. With subwoofer assistance, your mains, center, and surrounds will play louder, with less strain. And the subwoofer's power amp relieves your receiver's amplifiers of supplying all those watts for watt-hungry low-bass effects, allowing your receiver's amplifiers to "coast" with the fairly modest power requirements of midrange and upper-bass frequencies. So we all win. But the trick is getting the blend right, and with home-theater setups, it's frustrating and at times seems almost impossible.

Getting a Great Setup

Help is at hand in the form of a remarkably well-produced and complete home theater and stereo set-up DVD: the Sound&Vision Home theater Tune-Up (DVDI 0790), published by Sound&Vision magazine and Ovation Software. If you aren't aware of it or haven't seen it, you should check it out. Even for an avid enthusiast, it's useful, and--as impossible as this sounds, it's actually entertaining! Although this may seem like a shameless plug, it isn't. The DVD's audio test signals were developed by Sound&Vision Technical Editor David Ranada (an old friend and former colleague of mine). He is one of the best-informed individuals around on the subject of digital processing, home theater reproduction, video, and acoustics. The co-producer of the DVD is Ovation Software, who did the original Avia video alignment disc, heretofore one of the best video and audio alignment DVDs available.

Each time I use the Sound&Vision DVD, I find new information. It's hosted by an engaging Bill Paxton-type actor "Dave" and an agreeable non-shrewish actress, who plays his significant other. Together, chapter by chapter, and in easily understandable language, they go through the process of connecting your A/V receiver, DVD player, subwoofer, and five or more satellite speakers, as well as all the video connections, optical and coaxial digital links, and the analog audio hookups. And there are really clever demos to show the difference in video quality between S-video, composite- and component-video connections as well as concise explanations of interlaced and progressive-scan TV displays, High-Definition TV standards, and compatible progressive-scan DVD players.

Entertaining Test Disc

If anyone can make setting up those pesky subwoofer crossover frequencies entertaining and engaging, this pair can. Even little known facts--like setting your subwoofer's crossover control to its maximum position to let the receiver's built-in crossover work unhampered--are not overlooked. And some excellent basics about how to set the system menu for all your home theater speakers to "Small" or "Large" are also covered. Basically, any main, center-channel, or surround speaker using woofers smaller than 8 inches should be set to "Small." Now that's easy to remember!

Ever had the feeling that maybe, just maybe, not all your speakers are "in phase," their woofers perhaps not all pushing and pulling air at the same time along with your subwoofer?

No problem. The test signals gradually check phase with the sub and between every speaker in your system so you can check 'em all. And the tests for setting the subwoofer crossover frequency and level are the best I've ever encountered. You can do the tests by ear or, even better, with Radio Shack's inexpensive Sound Level Meter. There are even clear directions on the DVD on how to set up and use that invaluable accessory (it's about $35 or so at Radio Shack stores). You can access test tones for 6.1-channel systems and dts test tones as well. And excellent graphic animations illustrate proper surround, main-channel, and subwoofer speaker placement.

A Better Picture

I haven't talked much about the TV and video display alignment tests, but the DVD is even supplied with a blue filter to perform the color calibrations by eye. And who coudn't use a better-looking TV picture? Most consumer sets are badly misaligned right out of the box! If you're still confused about DVD movie and video-display aspect ratios and anamorphic formats, this disc will set you straight.

How to get hold of this excellent setup DVD? It's available on-line from a number of sources, including Barnes & Noble.com. The DVD's suggested retail price is $19.95 (US).

To most humans and animals, the distant rumbles of ultra-low bass frequencies signal impending danger. Dogs prick up their ears. Wild animals dart through the forest, seeking shelter. The subsonic reverberations of an approaching thunderstorm, earthquake or distant explosion are universal sounds of foreboding.

Producers and sound engineers of blockbuster movies know this, so they add lots of bottomless rumbles to the soundtracks of movies about war, monsters, submarines, aliens and catastrophic natural events. In big commercial cinemas equipped with an array of powerful subwoofers, these subterranean sounds heighten the realism of the movie surround sound experience, letting you thrill to the mayhem and catastrophe from the safety of a comfy movie seat.

Fidelity to the deepest bass sounds is just as important with music. Pop and rock musicians as well as classical composers understand the power of deep bass. It provides the propulsion for rock songs and is the foundation on which classical symphonies are built. The swell of a huge pipe organ or thrill of a bass drum lends grandeur to classical symphonies and movie soundtrack scores alike. Imagine the opening to Kubrick's classic film 2001 Space Odyssey without the powerful below-30-Hz organ tones and pounding drums of Strauss's theme from Also Sprach Zarathustra ?

If we are after realism and fidelity in our home theaters, we gotta have those subterranean frequencies. They are what make movies rock, whether in the cinema or your home theater. But they are tough to generate and a huge challenge to a speaker designer.

The Fundamentals Still Apply

It isn't clearly understood by most listeners that what many of us describe as deep bass isn't all that low. Taken at face value, the sub part of the subwoofer means that it should properly deliver deep bass that is below the range of a conventional woofer (bass driver) in a normal speaker system. The problem is that the output of most good conventional subwoofers starts to diminish in the 35-Hz region, and woofer output below that frequency begins to rapidly weaken. Still, many listeners are content with some solid bass in this range. And a rocking electric bass doesn't go deeper than 40 Hz. As long as lots of conventional subwoofers deliver adequate output in this region and a bit lower, many listeners are satisfied because there is at least the suggestion of deeper bass, if not actual subwoofer output at the frequencies that signal the approach of Godzilla. But what of those specifications that claim serious subwoofer output to 20 Hz or below? The manufacturers aren't lying: Some of those subs really do produce output at those frequencies, but the way it's measured involves some creative measurement techniques.

Conventional subwoofers do not just stop dead when they reach their limits of deep bass output. In speaker design lingo, we say that the subwoofer rolls off or gradually produces less and less output below a given frequency. For example, all of the highly regarded subwoofers that Axiom purchased and tested (which shall go unnamed) began to die at 33 Hz or above, although all the specifications claimed significant output to 20 Hz. In other words, a typical sub may have substantial output at 35 Hz, significantly less by 30 Hz, and perhaps a teensy bit at 25 Hz. The woofer cone may move a bit, but its output will be minuscule such that you won't hear it in a normal living room. Indeed, the only way for the manufacturer to measure it is to place the sub in a small space (a bathroom or closet would be best) along with the measurement microphone; we all know how well a subwoofer measures in the tiny interior of your car.

The Challenge

We feel sound as well as hear it, so for maximum impact (the profoundly deep sounds you hear from huge subs in some cinemas), you want strong, real, loud undistorted output to 20 Hz and below. Compounding the challenge is another obstacle that relates to how we hear. . To make 20-Hz and deeper tones audible requires a great deal more amplifier power and low-frequency output than do midrange and high frequencies. And conventional subs just cannot pressurize enough air in a big room to make those low sub frequencies audible.

This is how Axiom saw the challenge to produce a subwoofer that was still manageable in its dimensions, affordable to many, had an extremely powerful amplifier, and would move enough air in large rooms to deliver authentic low frequencies, undistorted, at very loud playback levels for home theater movies and music. Axiom knew that to achieve this performance, the laws of physics couldn't be ignored: a large box, a huge amplifier, and a big driver that wouldn't overload when it was pushed by hundreds of watts.

The Amplifier

Early on in the design process at Axiom, an all-analog amplifier design was considered—and rejected. Why? Analog amplifiers have only about 50% efficiency, so if the subwoofer required a 500-watt analog amplifier to drive a 12-inch driver in a large enclosure, it meant that the amp would draw at least 1,000 watts from the AC line. Unfortunately, there is limited access to total power from a house AC outlet. At the least, such a sub might trip the circuit breakers at peak output or cause brownouts and disrupt performance of other household electrical appliances, including your projector or TV.

The alternative to this scenario was apparent: a digital switching amplifier, because of its inherent high efficiency of 90%. Many existing subwoofers already use digital switching amplifiers because they are efficient, cool-running, lightweight, and relatively economical. But conventional digital subwoofer amplifiers have a severe limitation: no headroom. When a digital amplifier reaches it output limits, instant distortion results. And given that movie soundtracks and large musical works have sudden dynamic swings that demand sudden bursts of power, this didn't seem the appropriate choice.

The solution was to design an analog power supply (not a digital switching supply) that would give the digital amplifier plenty of headroom for large dynamic peaks. Additionally, output devices were selected for their ability to deliver huge amounts of current. The new design produces 600 watts with headroom to spare. Axiom also realized that an entirely new driver design would be required to handle such power and attain the design goal of deep bass response to 17 Hz with a maximum undistorted output greater than 110 dB SPL.

The Driver and the Box

A massive 12-inch aluminum-cone driver with a 3-inch diameter dual voice coil was designed (the dual voice coil lowers the internal impedance to 1.3 ohms, so the digital amp can utilize high-current drive)(pictured left). In terms of deep bass extension, Axiom knew that total box volume vs. driver diameter still rule, so a vertical enclosure measuring about 46 x 15 x 17 inches was proposed. By combining the new driver with the application of a very long tuned port (3 feet!) in a large enclosure and the assistance of the XLF (Digital Signal Processing of the response), the desired bass extension to 16 Hz in an anechoic environment was achievable.

Digital Signal Processor

But one enormous problem remained: how to make the subwoofer deliver smooth and consistent performance to its output limits (16 Hz) without overtaxing the driver and the amplifier. The answer was to use Digital Signal Processing, and a custom-designed algorithm. The latter term is in common usage amongst digital engineers (not so common to acoustical engineers though), and in essence, it's a kind of digital road map that can be programmed by the engineer to command a digital signal to perform in a particular way with a specific driver. The Axiom EP600's DSP circuit and algorithm know in advance the performance goals of the sub, the output capabilities of the powerful digital amplifier, and the capabilities of the new driver.

It automatically corrects any slight deviations of the big woofer away from the design goal, and it also prevents the subwoofer amplifier from exceeding its output limits and going into distortion. The result is a subwoofer that offers unprecedented performance. The EP600's output measured anechoically (in a room with total absorption) or in free air, extends to 17 Hz +/-1 dB and to 16 Hz +/-3 dB. Used in a typical room with the boundary reinforcements that normally apply, extension to 13 Hz is possible. The EP600's XLF (Extended Low Frequency algorithm) DSP enables maximum sound levels to an unprecedented 111 dB anechoic, and 122 dB SPL in a typical room, output and extension that are clearly able to reproduce Godzilla's footfalls at real-life levels!

And because of the DSP, the EP600 can't be overdriven into distortion. You can keep increasing the volume level with impunity. It will reach its maximum and go no further, nor can you damage the driver. All the time the DSP's algorithm tells the amplifier to stop delivering more power to the driver to prevent distortion.

While it's operating, the DSP constantly monitors the power supplied to the driver, correcting any tendency for the driver and system to deviate more than 1.5 dB away from the performance goal (linear output in an anechoic environment). What this means in practical terms is that if you feed any frequency between 17 Hz and 100 Hz to the EP600, it will deliver that frequency with, at most, an undetectable variation of 1.5 dB. And it will mine even lower frequencies with as much precision, all the way down to 17 Hz with the same 1.5 dB of variation.

Some of the EP600's other characteristics are relevant: It weighs 100 pounds, and you can request it in a horizontal version so you can conceal it behind a sofa or put it away at one side of the room. And for those willing to accept just 2 dB less in maximum output (109 dB anechoic/120 dB in-room) and a bit less extension to 19 Hz anechoic and 15 Hz in-room, there is Axiom's EP500, a somewhat smaller version with the same massive driver, slightly less power output (500 watts vs. the larger sub's 600 watts), and, at €1,217.00 EUR, a price that's around $600 less than the larger sub (the EP600 is €1,625.00 EUR).

For example, other things being equal (and each of the following may be manipulated to achieve certain gains at the expense of other performance factors), the larger the subwoofer box is in relation to the diameter of the woofer, the deeper the bass output will be. (One enthusiast I know installed a huge driver in one wall of a room in his house, using the adjoining room as the enclosure! When this is fired up, the entire house resonates. Is it any surprise that this gentleman lives alone?) Put another way, the smaller the box in relation to the driver, the less deep bass output will be. Or we can get somewhat deeper bass by reducing the driver size along with the box but sacrifice maximum loudness.

How low do we need a subwoofer to go to deliver audible output? Human hearing extends to about 20 Hz, and although there are frequencies deeper than that—some huge pipe organs actually produce a fundamental tone at 16 Hz— they are typically more felt than heard. Certain natural or man-made events such as earthquakes and explosions also produce lingering reverberations that we feel more than we hear. If you feel the vibrations in a church pew or in the floor, you are likely feeling 16 Hz or so, but actually hearing the second harmonic at 32 Hz. To most of us, hearing a 32-Hz harmonic of a pipe organ sounds really low and it is but in order to deliver real-life impact, a fine subwoofer needs to add that ultra-low  felt component at 16 Hz, and deliver significant output in the 20-Hz region.

Virtually all popular subwoofers achieve some bass output in the 20-Hz region, but they do so only through the assistance of room reinforcement and advantageous placement in the room. (And that's also how the sub's performance is measured, by advantageous placement of the measurement microphone in a area or node of bass reinforcement.) All of this works as long as the room isn't too big. In fact, many of us have experienced very deep bass in a car equipped with a good sub, because of the small volume of air in the passenger compartment.

But in a larger space like a big room, true 20-Hz subwoofer output is hard to get. And it's this content that adds the enormous "wow!" element to movie soundtrack effects, and furthers the realism of great orchestral music. Train crashes and artillery all produce frequencies in the 20-Hz region, as do orchestra bass drums, pipe organs, synthesizers and even some pianos.

Why a Trumpet Sounds Like a Trumpet

All notes from a musical instrument, deep bass included, are made up of a fundamental tone and harmonics, which occur at mathematical multiples of the fundamental tones and help give each instrument its tonal signature or identity. For example, even if different instruments—trumpet, sax, and piano—all play the same note of identical pitch and frequency, each instrument will sound quite different. This occurs because each instrument's harmonic makeup gives the instrument its distinctive sound. It's harmonics that make a sax sound like a sax and a piano like a piano. That's also why we are still able to hear a 16-Hz organ pedal tone, because we actually hear the 32-Hz harmonic, which is much louder than the 16-Hz fundamental. However, if our subwoofer doesn't reproduce any of the 16-Hz energy, then we won't feel as much and it won't seem as realistic. The same goes for soundtrack effects.

Attempts have been made (not really successful) to reduce the subwoofer enclosure size and try to compensate by using very large amplifiers and huge magnet assemblies (to take the extra power) in order to produce deep bass extension and output. But ultimately, box-size-to-woofer-diameter rules! You can extract tones as low as 40 Hz from a small sub by putting it in a smaller room in a favorable location a room mode or corner (a node in a room can give you 6 dB of boost). Similarly, some available ultra-compact and expensive cube subwoofers do produce fairly low frequencies, but they have real limitations in maximum output. They simply won't play low frequencies at anything approaching real-life loudness. If the sub's output is 9 dB down (-9 dB) at 32 Hz (about half the output at 70 Hz), you would need eight times the power to correct for the 9-dB loss (you must double the power for every 3 dB of boost applied). If you started out using a 200-watt amplifier, you would have to increase that to a 1,600-watt amplifier and then lose most of those gains to the driver required to take the power!

Let's say we wanted to design a sub that could truly reach the 20-Hz level or deeper with no more than a 4-dB drop in output in an anechoic environment. First, the laws of physics dictate that the box must be large. There is no way around this. You would also need to incorporate an efficient amplifier because true deep bass extension requires enormous output (over 400 watts) in order to achieve sufficient loudness at these frequencies. It also must have the power to drive a large woofer and move the requisite quantities of air.  

The Amplifier

Early on in Axiom's design process for its no-compromise subwoofer, an all-analog amplifier design was considered—and rejected. Why? Analog amplifiers have only about 50% efficiency, so if the subwoofer required a 500-watt analog amplifier to drive a 12-inch driver in a large enclosure, it meant that the amp would draw at least 1,000 watts from the AC line. Unfortunately, there is limited access to total power from a house AC outlet. At the least, such a sub might trip the circuit breakers at peak output or cause brownouts and disrupt performance of other household electrical appliances.

The alternative to this scenario was apparent: a digital switching amplifier, because of its inherent high efficiency of 90%. Many existing subwoofers already use digital switching amplifiers because they are efficient, cool-running, lightweight, and relatively economical. But conventional digital subwoofer amplifiers have a severe limitation: no headroom. When a digital amplifier reaches it output limits, instant distortion results. And given that movie soundtracks and large musical works have sudden dynamic swings that demand sudden bursts of power, this didn't seem the appropriate choice.

The solution was to design an analog power supply (not a digital switching supply) that would give the digital amplifier plenty of headroom for large dynamic peaks. Axiom's new EP600 and EP500 DSP subwoofers both utilize a powerful digital amplifier with an analog power supply. The analog power supply provides the needed headroom to prevent the digital amplifier from going into distortion.

Additionally, output devices were selected for their ability to deliver huge amounts of current. The new design produces 600 watts with headroom to spare. Axiom also realized that an entirely new driver design would be required to handle such power and attain the design goal of deep bass response to 17 Hz with a maximum undistorted output greater than 110 dB SPL.

The Driver and the Box

A massive 12-inch aluminum-cone driver with a 3-inch diameter dual voice coil was chosen (the dual voice coil lowers the internal impedance to 1.3 ohms, so the digital amp can utilize high-current drive). In terms of deep bass extension, Axiom knew that total box volume vs. driver diameter still rule, so a vertical enclosure measuring about 46 x 15 x 17 inches was proposed. By combining the new driver with the application of a very long tuned port (3 feet) in a large enclosure and the assistance of the ELF (Digital Signal Processing of the response), the desired bass extension to 16 Hz in an anechoic environment was achievable. (We also decided on an optional horizontal configuration to give users some installation flexibility.)

Digital Signal Processor

But one enormous problem remained: how to make the subwoofer deliver smooth and consistent performance to its output limits (16 Hz) without overtaxing the driver and the amplifier. The answer was to use Digital Signal Processing, and a custom-designed algorithm. The latter term is in common usage amongst digital engineers (not so common to acoustical engineers though), and in essence, it's a kind of digital road map that can be programmed by the engineer to command a digital signal to perform in a particular way with a specific driver. The EP600's DSP circuit and algorithm know in advance the performance goals of the sub, the output capabilities of the powerful digital amplifier, and the capabilities of the new driver. It automatically corrects any slight deviations of the big woofer away from the design goal, and it also prevents the subwoofer amplifier from exceeding its output limits and going into distortion. The result is a subwoofer that offers unprecedented performance. The EP600's output measured anechoically (in a room with total absorption) or in free air, extends to 17 Hz +/-1 dB and to 16 Hz +/-3 dB. Used in a typical room with the boundary reinforcements that normally apply, extension to 13 Hz is possible. The EP600's ELF (Extended Low Frequency algorithm) DSP enables maximum sound levels to an unprecedented 111 dB anechoic, and 122 dB SPL in a typical room, output and extension that are clearly able to reproduce Godzilla's footfalls at real-life levels!

And because of the DSP, the EP600 can't be overdriven into distortion. You can keep increasing the volume level with impunity. It will reach its maximum and go no further, nor can you damage the driver. All the time the DSP's algorithm tells the amplifier to stop delivering more power to the driver to prevent distortion.

While it's operating, the DSP constantly monitors the power supplied to the driver, correcting any tendency for the driver and system to deviate more than 1.5 dB away from the performance goal (linear output in an anechoic environment). What this means in practical terms is that if you feed any frequency between 17 Hz and 100 Hz to the EP600, it will deliver that frequency with, at most, an undetectable variation of 1.5 dB. And it will mine even lower frequencies with as much precision, all the way down to 17 Hz with the same 1.5 dB of variation.

Some of the EP600's other characteristics are relevant: It weighs 100 pounds, and you can request it in a horizontal version so you can conceal it behind a sofa or put it away at one side of the room. And for those willing to accept just 2 dB less in maximum output (109 dB anechoic/120 dB in-room) and a bit less extension to 19 Hz anechoic and 15 Hz in-room, there is the EP500, a somewhat smaller version with the same massive driver, slightly less power output (500 watts vs. the larger sub's 600 watts), and, at €1,217.00 EUR, a price that's less than the larger sub (the EP600 is €1,625.00 EUR).

It's a common scenario. With the move to streamlined flat-screen TVs, the space inside the set is miniscule compared to the big old CRT picture-tube sets, or large DLP/LCD rear-projection sets of years past, so new flat-screen TV's own speakers must by design be tiny. In the search for ever-thinner LCD or plasma displays, engineers have to use smaller and smaller speakers, whose output and frequency response is severely limited. Music and dialogue sound tinny, lacking clarity and devoid of any bass. Turning the volume up won't help in deciphering and hearing TV dialogue. The tiny cones of the speakers simply can't move any more to create louder sound—they just distort, which worsens intelligibility.

The answer to hearing TV dialogue from your luxurious flat-screen is to simply install a separate center-channel speaker to handle the movie dialogue and a small home theater surround system with a modest AV receiver/amplifier to power the center channel and left-right front speakers and surrounds for a more 3-dimension experience. And here's the huge benefit: using a dedicated center channel speaker with even an entry-level AV receiver lets you adjust the loudness of the actor's dialogue independent of the other speakers. So you can raise the volume of the dialogue over that of the background surround special effects and music, which sometimes may obscure the actor's speech.

The Axiom In-Wall On-Wall VP150 Center Channel.

Movie theater exhibitors have known this for years. That's why even early cinema surround sound systems always anchored the dialogue for movies to a big horn speaker centered behind the movie screen, designed to project clear dialogue to hundreds of audience members in the same way we cup our hands around our mouths to shout and make our voices maximally audible and clear.

Many center-channel speakers are dedicated horizontal designs, like Axiom's VP100, VP150, and VP180, with the woofers and tweeter(s) arranged in a horizontal array so the speaker can be easily placed on a shelf, in an equipment cabinet above or below your flat-screen display, or wall-mounted with a tilting bracket so you can aim the center speaker directly towards your seating area. But you don't have to limit yourself to a horizontal center for hearing your TV. If you have room for a good upright bookshelf speaker like the Axiom M2 or M3, it will work just fine as a center.

Once installed, you'll be amazed at the improvement in movie dialogue clarity with a good center-channel speaker as well as the added benefits of much better sound quality for all kinds of music from TV shows and DVD/Blu-ray discs.

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Was your New Year's Resolution to get in shape? Well, the Cranky Audiophile's Guide to Audio Facts and Fallacies is sure to get your heart racing and your blood pumping! Read on as Alan Lofft debunks popular audio myths, and then weigh in with your opinions on our message boards!

Q. I've been told that in order to keep cable length consistent, the speaker wires from my new receiver to each speaker should be cut to identical lengths; in other words, the cable to the left front speaker should be the same length as the one to the right front speaker and to the center speaker. Do you agree?

A. No, I don't agree. If you use speaker cable of sufficient thickness 12-gauge or 14-gauge for all your speaker connections, the resistance of the cable is so insignificant that you can cut each of your cables to whatever length you need to conveniently reach each speaker. Just use inexpensive 12-gauge speaker cable such as Axiom's bulk cable up to lengths of 75 feet or more with no losses in the audio signal or degradation of any kind.

As the gauge number increases (12, 14, 16, etc), the cable gets thinner. Lower numbers mean thicker cable, which is desirable for longer runs and lowest resistance. For short connections, 10 feet or less, 16-gauge is ample; use 14-gauge for lengths up to 25 feet; and 12-gauge for lengthy runs. To keep things simple, use 12-gauge everywhere and cut whatever lengths you wish.

Q. Which TV display technology is best? LCD or Plasma? Some store sales people claim that plasma sets use twice as much power as LCD sets. Others say that plasma screens have better "blacks". Can you enlighten me?

A. With recent technology advances, both plasma and LCD flat screens are now capable of excellent picture quality; so close that when viewed head on with carefully adjusted picture displays, they are almost indistinguishable even by trained viewers. However, some differences remain. If viewed from angles to the side, all LCD displays show a loss of contrast between black and white areas and degraded color consistency. This will vary from one brand to another and you can easily check that in a store. Just watch a high-quality HD broadcast on an LCD display and walk from one side to the other to see if the image quality deteriorates when viewed at angles from the side. Plasma displays are not subject to this problem; the image quality remains constant in contrast and color even viewed at extreme angles.

Plasma displays have traditionally had better "blacks" more intense than LCD displays, but new LCD models that use LED edge lighting and/or "local dimming" driven by image content produce excellent contrast and black levels.

If you view a lot of fast-moving sports, plasma sets are a better choice: their pixels turn on and off faster than LCDs, but new LCDs use multiple refresh rates to limit the "ghost trail" of fast-moving objects visible on some older LCD displays. A hockey or basketball game in HD on a store display will reveal if an LCD set has any "smearing" problems with fast action.

As to power consumption, the early plasma displays did consume a lot more power than LCD displays. New plasma sets, however, have reduced power consumption to almost equal that of LCD displays. You can check the power consumption in watts if you look at the owner's manual online or check the specs in the store. Be sure to compare sets of the same or similar screen size. Large-screen sets will consume more power than smaller ones.

Q. I was told that "dirty power" from the wall outlet in many homes can be blamed for TV interference and poor sound quality and that I should buy a power conditioner along with my new AV receiver and home theater system. What are your thoughts?

A. The myth of "dirty power" ranks up there with high-priced branded speaker cables as one of the biggest scams of the audio/video industry. All solid-state amplifiers and electronic components contain their own power supply sections with filters, capacitors and rectifiers designed to smooth out and remove any anomalies from the incoming power. No further "conditioning" devices are required. (I'm not speaking of surge protectors that may be beneficial in areas frequently plagued by power outages or lightning strikes.)

Use the money you save by not falling for the power conditioner scam to buy more great music or excellent speakers that really do make a difference in sound quality.

Q. It seems that turntables and vinyl (LP) analog records are seeing a revival in popularity because of backlash to the harsh "digital" sound of CDs and other digital media alleged by some audiophiles. Do vinyl LPs really sound better than CDs?

A. There has been a small resurgence in the sales of vinyl albums and turntables relative to the enormous popularity of digital media like CDs, DVDs, Blu-ray discs, and online music sales, but the reasons behind the vinyl uptick are triggered by nostalgia for the large-format album covers (large LP jacket notes are a lot easier to read than the tiny print in a CD booklet) album artwork and because analog recording and playback is simple and understandable! You can see the vinyl platter revolving (what fun it is to see the label going round and round) and the tiny squiggles in the grooves. With CDs or music files, you can't see a digital stream of 1's and 0's, and you almost need a graduate degree in math to understand digital sampling and quantization, which make digital recording media seem clinical and unfriendly.

But don't talk to me of superior sound quality from vinyl discs. The only reason an LP can sometimes sound great and many do when everything is done just right, including cleaning the vinyl disc is that great care was taken by the recording engineer in the choice and placement of microphones and later mastering of the album. Conversely, digital recording is a transparent medium that reveals the best and worst of recording practices.

Done well, a CD can be a revelation in sound quality; done poorly, as with many contemporary pop/rock recordings with severely compressed dynamics and exaggerated midrange (for airplay), a CD can be unlistenable. Vinyl, because of its poorer frequency response, tends to make bad recordings more listenable by concealing the worst distortions in layers of extraneous hiss and groove noise. Digital recordings reveal all the warts and poor choices made by the recording engineer.

However, any claims that analog vinyl recordings inherently sound better than digital recordings are ludicrous. The analog medium is so plagued with various distortions, let alone the dust, dirt and ticks and pops of imperfect vinyl pressings, that it often makes listening to vinyl serious work as you try and ignore the extraneous noise, audible wow or flutter and distortion on loud passages of an LP.

There are hundreds of wonderful sounding and terrible sounding vinyl discs in my own collection, just as there are thousands of great and poor-sounding digital recordings. A great analog recording can certainly match the sound quality of fine digital playback, but it's rare, and the tedium of cleaning LPs and other intrinsic flaws of analog make it, for me, a charmingly nostalgic but obsolete medium for music recording and playback.

Q. In many areas of consumer purchases, increasing price usually brings greater sophistication and refinement for example, in automobiles. Does this also apply to CD players and loudspeakers?

A. In terms of sound quality, definitely not in CD players or DVD players. The 1's and 0's that represent the music signals are digital streams read by a laser and so long as they are complete they will be reformed by the player's digital-to-analog converters into analog music signals that sound exactly the same from a $100 player as from a $4,000 tweak "high-end" playback unit. The digital converters are mature technologies and any distortions are so far below audibility that they're buried in the noise floor and require careful test instruments to detect them. Put to a controlled blind comparison with identical discs running in a low-cost player vs. a high-end player with output levels equalized, no audiophile has been able to distinguish the low-priced player from the costly one beyond the level of chance.

Loudspeakers are different. As analog devices, there are refinements and care in design, measurement, and manufacturing that come with higher cost and yield improved sound quality—up to a point. However, in my long experience of editing audio and audio-video magazines and doing hundreds of listening comparisons in controlled (mostly double-blind) environments, it's entirely possible to find compact speakers for less than $400 a pair that can deliver a highly satisfying musical experience and reproduction of all but the very deepest bass. Getting profoundly deep and powerful bass and very loud clean playback costs more, but that's still possible at affordable levels in my experience, for less than $2,000 per pair. Beyond that, it's largely cosmetic detail (exotic finishes for example), marketing expense and dubious claims to sound quality that raise the prices.

That's it for this round: five more facts and fallacies to stew over in your leisure time. There are more, but those will appear in a future installment of Axiom's AudioFile!

Years ago as a passionate enthusiast, and long before I began editing magazines and writing articles about sound reproduction and video, I was totally convinced that deep bass had directional qualities. I even went so far as to build a large pair of transmission-line stereo subwoofers, great coffin-like enclosures, one for the left channel and one for the right, which stood at the front of the room not far from my satellite main speakers. (My mate at the time predicted I'd likely request burial in one of the subwoofers, so great was my fervor for all things audio!)

Directional Bass?

Back then, two subwoofers for "stereo bass" seemed entirely logical — if you watch a big bass drum in a band being played, or a marching band passing by in a parade, the "whomp" of the bass drum seems to come directly from the drum itself. It took me years to realize that the directional part of the "whomp" sound is in fact at a much higher frequency than the 30-Hz bass energy from the drum. When the mallet strikes the drum's diaphragm, the higher-frequency information provides the directional cues that tell your ear/brain hearing mechanism where the drum is.

But the deep bass energy of the drum's diaphragm pulsing back and forth 30 times per second radiates long pressure waves in all directions and it's that bass energy that gives the drum its power. And that is exactly the energy the subwoofer produces so well, while the smaller satellite drivers — even the compact surrounds in a 5.1-channel system — handle the initial mallet sound to tell you the drum's location. The same thing happens with soundtrack special effects like explosions or thunder and lightning. The crack of the lightning or initial explosive burst is higher in frequency and gives you the directional information, so the midrange driver and tweeters (or upper-bass octaves of the woofer) easily reproduce those sounds. But the deep bass reverberations of thunder go to the subwoofer.

Crossovers and Filters

Once you understand this, then the operation of a multi-channel satellite/ subwoofer system becomes clear, as well as the concept of "bass management." To function properly, the system must extract the deepest bass energy of the drum or explosion from the rest of the audio signals and send it to the subwoofer — in other words, the non-directional parts of the bass below 100 Hz (approximately).

To divide the bass frequencies from the high frequencies and direct them to the drivers best equipped to reproduce them, we use filters. Operating together these filters make up a "crossover." Most crossovers are comprised of a "low-pass filter" and a "high-pass" filter. The low-pass filter lets the low bass through (passes the lows) but blocks the high frequencies from the subwoofer (or woofer). The high-pass filter lets the higher frequencies through to the midrange and tweeter but blocks the deep bass from reaching those drivers. This is a typical crossover in a "2-way" system that uses two filters. (It's somewhat analogous to those mechanical change-sorting devices that let the smaller dimes-the high frequencies-pass through a small slot while the larger quarters and silver dollars--the bass frequencies-will only fit through the bigger slots.)

There are also individual crossovers in your main and satellite speakers (you cannot have bass frequencies reaching the tweeter or the tweeter would burn out) but the real work of separating the deep bass from the other frequencies and sending it to a subwoofer in a 5.1- or 7.1-channel home theater system happens inside your A/V receiver. There, an active digital crossover that is part of the "bass-management" circuit can be adjusted to specific frequencies and characteristics that best suit the capabilities of each of your speakers. Every Dolby Digital/dts 5.1 or 7.1 channel receiver (or A/V preamp-processor) has this bass-management circuit with its accompanying menu system that you can access.

Small and Large

In the bass management setup menu, "Small" and "Large" don't refer to the physical size of your speaker enclosures so much as to whether or not each speaker in the system is capable of reproducing powerful deep bass below 80 Hz (note the emphasis on "powerful"). Nevertheless, the basic rules of physics that dictate small boxes cannot reproduce powerful deep bass can be used as a rough guide to manually adjusting your home theater's bass management.

For example, typical center-channel and surround speakers (and in lots of systems, the main speakers as well) are relatively small so as not to be obtrusive. Most well-designed ones of ample size (not the mini-cubes) will reproduce upper bass — from around 100 Hz and above-smoothly and consistently.

But when deeper bass frequencies below 100 Hz reach those speakers, the satellites do not have the power and air-moving properties (i.e., large-diameter cones) to adequately handle the bass, so the speaker's bass output begins to "roll off" or diminish. That's why you should set your center channel and surround speakers (and the mains if they are bookshelf size) to "Small" in your AV receiver's bass-management menu. The receiver's circuitry then inserts electronic high- and low-pass filters at a preset frequency (or one you manually select) at, typically, 80 Hz or 100 Hz.

80 Hz

Why 80 Hz? Because deep bass below that frequency (the aforementioned energy of the bass drum) is not directional; it's just low-frequency energy that needs the big woofer of a subwoofer (plus its powerful self-contained amplifier) to generate. So that's the process you trigger when you set your center and surround speakers to "Small". The receiver's bass management circuit routes the deepest bass to the subwoofer and all the upper bass and highs to the center and surround speakers (and to the main speakers if they are bookshelf models).

Note too that the digital filters inside your AV receiver don't just suddenly cut off all frequencies at 80 or 100 Hz. They have "slopes," so the process of extracting deep bass is a gradual one - as the bass gets deeper, the crossover filters remove more and more of it for the subwoofer and gradually send less of it to the smaller satellite speakers. The bass frequency ranges of sub and satellites overlap, so a seamless and inaudible transition occurs between the subwoofer and your center and surround speakers' upper bass and midrange. That's why you shouldn't notice or "hear" deep bass from the subwoofer in a conventional sense. Properly set up, the deepest bass should seem to come from the main front speakers in your system, because the sub is only supplying the lowest energy component of low-frequency sounds. (Depending on where the subwoofer is located you may hear knick-knacks vibrating or resonanating — even picture frames — which are set into motion by the bass energy from the sub.)

Audio and home theater enthusiasts often worry about "losing bass from the QS8s or the rears" as one Axiom customer recently put it. That would only occur if he were to set his surround speakers to "Large." Deep bass would then be sent to the surrounds, which aren't able to produce deep bass.

If you use floorstanding front left and right speakers, most receivers enable several options that let you set the mains to "Large" and choose whether or not to have the AV receiver also direct bass to the subwoofer. That may work well in lots of rooms, but be certain that your AV receiver's bass management filters also direct bass from the center and surrounds to the subwoofer and/or to the Large mains. Most do.

DVD-Audio and SACD

In this discussion, I've ignored the issue of bass management as it applies to DVD-Audio and SACD, partly because the history of the two formats is checkered with missteps and false assumptions on the part of the hardware developers and mixing engineers. Nevertheless, since a small percentage of enthusiasts, including this writer, have experimented with both formats and value SACD or DVD-Audio recordings when they are well done, some comment is required.

Five Big Floorstanders

When the formats were introduced, there was a movement to have all the speakers in a DVD-A or SACD playback system be large, floorstanding speakers-impractical for all but those with extremely large listening rooms and the patience to try and position themselves in the middle. In such a setup, the DVD-A or SACD player would output full-range signals to all channels. From a practical point of view, it quickly became evident that even mixing studios didn't have room for full-range rear monitor speakers so engineers quickly adopted smaller bookshelf models for their studio mixing setups and utilized a separate low-frequency subwoofer channel. Still, the initial approach left a residue of belief that for "true" DVD-Audio and SACD playback, large full-range rear speakers were required. Worse, many early DVD-Audio and SACD players lacked proper bass-management circuitry. A few A/V receiver processors permitted the receiver's bass-management circuit to operate using the multi-channel inputs normally reserved for DVD-Audio and SACD playback.

No Delay

Complicating the issue was the fact that early DVD-A and SACD players did not incorporate digital delay for the rear channels, with the result that if the seating area was even a few inches closer to the rear speakers than to the front, you'd hear the rear channels before the sounds from the front, and the imaging would collapse to the rear speakers, which ruined the multi-channel illusion. (No domestic rooms are large enough to provide long enough natural delay times to prevent rear speaker sound from confusing your ear/brain hearing mechanism.) That's why all good bass-management circuits must include a distance configuration and mode that inserts appropriate digital delay times for ambient and rear-speaker sound output. Delayed by 15 to 30 milliseconds or more, the rear-channel or ambient sounds arrive a split second after those from the front, which keeps our ear and brain happy in forming the illusion of a complete 3-dimensional soundstage that approximates what might occur at a concert, club or outdoor event.

The happy solution is that accurate music-only DVD-Audio or SACD playback does not suffer when properly processed through an AV receiver's internal bass management circuit or external processor. The low frequency foundation of jazz, rock or orchestral music still goes to the subwoofer, leaving the smaller surrounds, center (and bookshelf main speakers) to handle all the upper bass, midrange and highs.

And to reassure those with lingering doubts, smaller surround speakers like Axiom's QS8s or QS4s, or direct-radiating surrounds will deliver highly convincing multichannel DVD-Audio or SACD playback so long as the signals go through proper bass management and delay circuitry with a subwoofer to properly convey the deepest bass in the music.

Bruno's question (slightly edited):

It's something I never understood. Why, in home movies, DVDs or Blu-ray, is there such a big dynamic range? You go through a soft passage where you can barely hear the dialog and a second later... BANG! . .the whole house is shaking with extremely high volumes. The reason I say home movies is because this high dynamic range doesn't seem so high at the theaters for some reason – or at least not to me. The dynamic range of movies viewed at home seems to be much more extreme than in the cinema.

For clarity, I've labeled the responses with initials (AL), Floyd (FET) and Sean (SO):

AL: Bruno, there's no question that the dynamic range of Dolby Digital soundtracks on lots of special effects blockbuster movies is too great for a lot of domestic environments. The mix is certainly the same as the one used in commercial movie theaters. I think there are a couple of factors that somehow make the huge dynamic range more acceptable in a large cinema than at home.

The size of the space and number of bodies in the seats plus all the absorptive upholstered seats in big theaters somehow "soaks up" the dynamic range better. At home, our relatively small rooms just generate too much immediate and very loud reverberant energy that can't go anywhere and get absorbed, so it's just too much acoustic energy impinging on our ears.

FET: Actually it is probable that the reverberation time in typical homes is lower than that in typical cinemas. Some of what we experience may be related to expectations – big room, big screen, big sound: OK. Small room, small screen, big sound: maybe not. Personally I have never had a problem, but I never play movies at "0" dB "reference" level. Most people play movies several dB lower at home.

AL: Also, the ambient noise level in a house from the heating/AC system plus a refrigerator/freezer and outdoor city urban noise is usually significantly higher than in movie theaters. Cinemas are quite well insulated to keep the ambient noise at a very low level so the available dynamic range can be played without having the peaks at deafening levels.

FET: When I saw "Avatar" at an IMAX, I could hear the air conditioning units on the roof, and hum from the amps through the loudspeakers – cinemas screw up too! The bass was obviously "one note", but I don't know whether that was the playback or the recording. Have you ever noticed the similarity in explosive sounds in movies and on TV – I think they all use the same "boom" clip.

AL: At home, ambient noise causes us to shift the range higher so the softer sounds can be heard above background levels, then when a peak comes along, it's way too loud.

FET: Yes, this could happen, but the background noise would have to be quite high – and I guess in some homes it could be.

Finally, FET's formal response to Bruno's question, followed by SO's comments:

FET: First of all we cannot assume that the soundtrack on a disc and that in the cinema is identical – the sound on the disc has gone through an additional mastering operation during which an engineer has the opportunity to alter a number of variables, including dynamic range. We don't know what, if anything has been changed, which makes discussion of this observation a bit uncertain. . .

However, assuming that the soundtracks are identical, there is another variable – the audio system in the cinema itself. If we are talking about top-line cinemas the dynamic range and bandwidth can be substantial. If we are talking about older cinemas or your local multiplex, the audio system may well not be up to the highest standards in terms of being able to reproduce the lowest frequencies, or the highest sound levels, resulting in less "impact" during big sound effects. So-called "standards" for setting up cinemas are sadly inadequate, and individual operators are sometimes known to go in after calibration and set things the way they like them. Frankly, if you have truly good loudspeakers, including subwoofers, at home, and have properly set up your own system, you may well be hearing something better, and closer to what was intended than you might in a garden-variety cinema.

Thinking on the "dark side" perhaps the home system is overloading (amplifiers and/or loudspeakers), causing distortion, clipping, or other sorts of unpleasant misbehavior during crescendos.

If your home system is up to standard, and properly calibrated, and you don't like the "startle" effect of a wide dynamic range, that is a totally different matter, for which there is no technical solution.

SO: I don't have much to add except that in homes there are other factors that may come into play that influence the "preferred" dynamic range of movies.

Differences in active attention of listener' in cinemas, you are usually giving your full attention to the movie; at home we are often multi-tasking and playing movies at lower playback levels. In this situation, the wide dynamic range may be a distraction to multi-taskers and present a problem with speech intelligibility at lower playback levels. Solutions like Dolby Volume and their dynamic range limiter (for late-night viewing when you don't want to disturb the neighbors) may be a solution for this situation. I have not actually tested Dolby Volume so I can't comment on how well it works: http://www.dolby.com/uploadedFiles/Assets/US/Doc/Professional/dolby-volume-tv-techpaper.pdf

Floyd is correct that there are specialists who remix films slated for DVD release. Bob Margouleff and Brant Biles at Mia Casa do this primarily as their primary work: http://www.micasamm.com/newsite/

In Zacharov and Bech's book, "Perceptual Audio Evaluation," they claim that for most program material, the preferred playback level for most people in their homes is about 10 dB lower than "reference level" when their system is properly calibrated.

So there you have it. If readers have further comments, please post in the Axiom Forums.

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Dr. Floyd E. Toole is the former vice-president of engineering for Harman International, a former president of the Audio Engineering Society, and for 25 years was an acoustical scientist at Canada's National Research Council. He is the author of "Sound Reproduction: Loudspeakers and Rooms".

Dr. Sean Olive is the Director of Acoustic Reseach, Corporate R&D, at Harman. He did extensive work at Canada's National Research Council with Dr. Toole prior to joining Harman. He authors a blog, Audio Musings.

Thanks to Don Tapscott, Futurist and Hammond B3 Player; Stephen Stanley, Singer Songwriter, formerly of Lowest of the Low, Andrew Welker, Lead Engineer and Vinyl Aficionado and Vlad Muller, Industrial Designer. I'd really love to hear your comments – please post them below.

The Speakers:

The Subwoofer:

Improving Your Speaker's Fidelity:

Convenient Playback Options:

"Speakers all come with various rated frequency ranges and it’s easy to see the change within a brand. For example, one speaker company offers a bookshelf speaker with a frequency range of 55-20,000 Hz, another with a range of 40-20,000 Hz, and some tower speakers with a range of 35-20,000 Hz and even 30-20,000 Hz. So the implication is that as you move up the speaker food chain (within the same brand), the frequency gets lower on the bass end. But, some speakers costing a lot more actually have frequency specs that would appear to be much worse! For example, when I look at Infinity, then Axiom, then Paradigm, and then Rockets, I can't see any consistency with the frequency range and the price. How can a speaker with a frequency range of 60-20,000 Hz cost four times as much as a speaker that has a rating of 30-20,000 Hz?"

The short answer is that none of these frequency response ranges can be compared, for reasons that will become clear.

To get a better idea of frequency response, imagine yourself sitting at the keyboard of a grand piano (don’t worry--you won’t have to practice!). If you push the bottom key on the keyboard, the felt hammer inside the piano strikes the longest string, which then vibrates back and forth 28 times per second (a frequency of 28 Hz). If you then play middle C, pushing the key with the same pressure, and then the uppermost key on the piano (somewhere in the 4,000-Hz range), the resulting tones should emerge from the piano at about the same volume or intensity. If the piano has been finely crafted, we can assume that any key played with the same pressure over the piano’s entire keyboard should emit a sound at a particular frequency at the same volume or amplitude. If one key produced a noticeably softer sound, and another a much louder sound, it would be difficult for the pianist to control the overall effect he or she wanted to create.

Now, let’s say we make a recording of every key you played on the piano, using a fine-quality studio microphone that responds equally to all sounds the piano makes. If the microphone has a smooth frequency response--and really good studio mikes do--then the resulting recording, stored on a digital medium or even on a fine Studer analog tape machine, should be an accurate sonic replica of that piano’s sound.

Now the big leap: if we play back the digital or analog tape of each piano key being played with the same force, and amplify the electrical signals with a smooth linear amplifier, feeding the output to a theoretically perfect loudspeaker, the speaker would reproduce each piano tone at the same intensity and would sound equally loud to your ear, just like it did in real time when you sat at the piano keyboard. We could then say that our theoretical speaker had a frequency response of 28 Hz to 4,000 Hz, +/- 0 dB, roughly the frequency range of a piano keyboard (more about the dB in a moment).

But no speaker is perfect. Consequently, some tones may emerge from a given speaker somewhat softer or louder than others. We measure these variations in the speaker’s output--its frequency response--with the decibel (dB), a unit of relative volume, 1 dB being the smallest change in volume that most of us can detect. A difference of 3 dB is quite noticeable. A difference of 10 dB subjectively sounds like "twice as loud," or "half as loud" if, for instance, the speaker’s output dropped by -10 dB at certain frequencies.

To cite a specific case, if the Axiom M80 reproduces the sound of the A above middle C at 440 Hz, and a second tone at 3,000 Hz, the two tones will be within, at most, 3 dB of each other in intensity. But if we play the 28 Hz tone, the M80’s output at 28 Hz won’t be as loud. If we measure it in an anechoic chamber, it may be at -6 dB. (The M80’s output at 25 Hz is -9 dB. It’s much harder for woofers to reproduce deep bass as powerfully as midrange frequencies.) Not only that, but our ears are not nearly so sensitive to bass as they are to midrange sounds, so, relatively speaking, the speaker has to work even harder to produce audible bass. Once placed in a room, a speaker’s deep bass output is helped by "room gain," so the differences aren’t quite so dramatic.

A simple claim of frequency response that cites two frequency extremes unqualified by a dB specification (e.g., frequency response: 34 Hz - 22 kHz) is meaningless and useless. It may mean that although the speaker responds at 34 Hz--the cone moves a bit, perhaps--nothing will be audible because the speaker's response at 34 Hz is at -30 dB and inaudible! On the other hand, if Axiom states that the M80’s frequency response is 34 Hz - 22 kHz +/-3 dB, this indicates that every tone that emerges from the M80 will be within 3 dB of any other over that entire frequency range.

Moreover, manufacturers often use different methods of measuring frequency response, because there are still no universally accepted standards. That said, reputable companies such as Axiom and some other Canadian builders do careful measurements that are qualified by dB ratings.

So to return to the original question, all those figures quoted without the dB qualification are not comparable. You must begin by looking carefully at the extremes and the dB qualification. There may be several different measurements, an anechoic one and a room measurement. You can always assume that the most extreme variation will occur at the lowest bass frequencies, because the most expensive aspect of speaker design is building in deeper and deeper bass output. For example, the M22ti’s response is stated as 60 Hz to 22 kHz, +/-3 dB, whereas the M80’s is 34 Hz - 22 kHz, +/-3 dB. The M80 supplies almost a full octave of deeper bass output than the M22ti, which is why a subwoofer is wonderful addition to extend the M22i’s low-frequency coverage. There are, of course, many other reasons why speakers with similar, honestly stated frequency ranges may differ dramatically in price and performance, not the least of which will be determined by the entire family of amplitude response curves that make up the total performance of the speaker. Beyond this are there are the cosmetic and design factors. But that's for another issue of AudioFile. 

We've had a lot of requests from customers who are moving back to stereo speaker setups (partially I think because when we introduced the LFR1100, many people started to listen to music in stereo again, and really enjoyed that set up)

Customizable Face Plates

3U Zone Control Amp With Customized Wooden Faceplate

First up on the list of new products is our new customizable faceplate that we're going to be going to for all of the new electronics, as well as the existing amplifiers and DSP systems for our LFR omnidirectional speakers. You'll be able to get these fronts in a brushed aluminum look, very similar to what we have been shipping these products in up until now. But the exciting part is that if you want to customize your electronics to match your speakers – whether it's a stock vinyl, a custom vinyl, a custom wood veneer, or even a custom match finish, we can now offer that.

Pictured above is a prototype using our standard Boston Cherry finish for a faceplate. (We're still playing with the design, so this is truly a 'sneak peek' into what we have been working on, but it gives you an overall taste of what things are going to look like.)

Preamplifiers

3U Amplifier in Real Wood, with a 2U Preamp and a 2U DSP in Real Wood.

The stand-alone preamps units will come in our slimmer '2U' chassis – the same size as our current LFR DSP chassis. The entry-level version has three inputs: RCA in-and-outs only.

The step-up version has five inputs, two of which are balanced. It also has dedicated true balanced outputs on it. So if you run balanced components in your system, or particularly if you are using it with an ADA 1250 or 1500 amp, it's an excellent way to use those LFR inputs on those amplifiers.

As options for the two stand-alone amplifiers, we're going to be offer various modules as we go along in the future. One is our exciting new "Axiom Play" wireless module, which will allow streaming capability built into the preamplifier.

We're also looking at introducing a phono pre-amp module. It's likely going to be both moving coil and moving magnet selectable with selectable loading.

And we're also looking at a USB DAC which will let you take a USB device like a laptop computer, or certain tablets or smartphones, and plug them directly into the amplifier to digitally play back the audio files on the device.

Integrated Amplifiers

Both of the stand-alone preamps are available in integrated pre-amps as well, so you'll get the same features as the two pre-amps described above, with the addition of a two-channel ADA 1000, which is 125 watts x 2 into 8 ohms, built in all into the same chassis. That has to go into the larger chassis.

So if you wanted to build a very simple two-channel system around a turntable or even something to plug your tablet or smart phone in, that unit with a pair of speakers and your source component makes a complete system.

Zone Control Amp in traditional brushed black aluminum

One other thing that we're going to be offering both as a preamp and an integrated amp is what we call a Zone Preamp or Zone Integrated Amp. By 'Zone' all we mean is it's configurable in anywhere from four to eight channels (in even numbers - so four, six or eight channels) and as a stand-alone pre-amp it will allow to select and channel signals to different amplifiers for whole-home audio. You have the ability with the three inputs to transfer those three main inputs to all of the four, six or eight output channels. You also have the ability to have a separate input for the four, six and eight external channels that are not slaves to the the internal channels.

What that means is if you wanted to have different devices playing on different systems in your house, you could do that. But if you wanted to play the same music in every room of your house, just flip a switch and you're sending the same source to all of the amplifier channels.

It's something we've had quite a bit of call for and it will be exciting to have this product line coming out. It has been an exciting period of development at Axiom.

Let's take a screened-in outdoor room as an example. This is an environment that is as close as you're going to get to an actual enclosed room. You've got boundaries: you've got a rear wall, you've got side walls. You're going to get reasonable sound reinforcement from those boundaries. This helps with bass, as well as sensitivity and efficiency (or the perceived level of the speaker for a given amplifier power.)

Why is this important? When you've got the speakers in a typical room, a lot of the efficiency you get is because of the boundary loading (the reflections that are in the room). If we have a pair of outdoor speakers that are truly in free space (so that they're not mounted against any boundary or near any walls) the perceived level for a given amount of amplifier power goes down significantly. So you need to keep that in mind. If you're going to try to fill a large open patio space with a pair of speakers, even if they're mounted up against one wall boundary, you're going to have to have more amplifier power available for whatever listening level you're looking to achieve than you would in a typical living room or family room.

Tip: Don't skimp on amplifier power just because it's an outdoor system. Unless you're going to be listening at just the quietest background levels, you may find you need more amplifier power than you think.

One other thing to keep in mind is that sound doesn't travel very well at some frequencies in open space. Again, this is because you don't have the enclosed environment of a room. Having multiple outdoor speakers as opposed to just a single pair of speakers is better if you are trying to fill an area with good sound quality.

In an environment such as screened in room that is maybe 12 or 15 feet wide, you're still going to get good stereo reproduction. In an environment where you are placing speakers as far apart as you would in a typical listening room, you can still expect to get good stereo sound.

But you have to think about that a little bit if you are trying to fill a large open space with sound. Stereo actually can be a detriment in those cases - it places some instruments in the left speakers and some instruments in the right speakers, and the distances involved between speakers means that the instruments are not blending into a stereo presentation.

Tip: What you might want to try is running a "mono" setup. This can be done in software if you are using digital files. Some pre-amps and processors have a mono setting you can use as well. This mono setting essentially allows you to mix the right and left channels into all the speakers in your setup, so you get an environment where you get a good spread of sound, and you're not worried about the distance between the speakers causing strange sounds.

For more information on creating an alternate mono library in iTunes, visit this link: https://discussions.apple.com/message/11789229

Another thing that is very easy to do with digital files is something called "normalizing". That's something that you might want to do if you're using iTunes for instance. You can keep a normalized version of your library for use exclusively outside. Normalization will compress the levels so that, for example, if you have a recording that has very very quiet parts, it will bring them up. Those quiet parts would be completely inaudible in an outdoor setting without normalization.

For more information on normalizing volume levels with iTunes, visit this link: http://support.apple.com/kb/HT2425

Do you have software that you use for normalizing or for creating a mono library? Or other tricks you are using in your outdoor installation? Please share below!

We've already covered the basic floorstanding positioning, toe-in, bookshelf speakers - whether they're mounted on stands or bookshelves – center channels, subwoofers and so on. Today we're going to talk about what happens if you have a very large room, a very small room, a rectangular room or a square room: what should you do in those environments.

Rectangular Rooms:  We'll start with what is most typical: a rectangular-shaped room where you'll have a long wall and a short wall. There is some argument as to where you should ideally position your system: whether you should put them on the short wall firing down the length of the room, or whether you should be in the near field and on the long wall. That's going to give you a little bit different perspective. Placing the speakers on the short wall on the narrow dimension of a rectangular room is going to limit the width and the overall soundstage size to a certain extent. But it can also result in more room-filling sound for a smaller seating area.

If it's possible and your room is wide enough, I tend to prefer doing the set up on the long wall. You may be sitting a little bit closer to the speakers, but what will happen is that now the main sidewall reflections are further away from the speaker, and they will aid in the size and enveloping sense of space with your loudspeaker setup.

Square Rooms:  If you've got a square room, unfortunately that's pretty much the worst case scenario when it comes to a basic room acoustics. Any standing waves or any nodes that occur along one dimension of the room will also occur on the other dimension of the room, at the same sorts of frequencies. So those rooms can be quite difficult. One of the things you can try there (if you have the option and aesthetically it works for you) is to actually mount the system with the center point between the speakers being one of the corners of the room. So you're essentially mounting the speakers on the walls that are coming out diagonally from that corner.

That can actually give you a better level of balance, particularly at low frequencies, if you're stuck with one of these square-shaped rooms.

Small Rooms:  An acoustically small room is one where the longest wall is less than 14 feet. In those environments, you're going to be listening in the near field –– there's nothing you can do about that. In some cases, you're going to be forced to have your listening position right up against the back wall. Unfortunately that's really bad acoustically for getting a large amount of bass and mid-bass loading.

If you're forced into that situation, try pulling your couch out from that back wall –– even if it's just six inches or so –– rather than having it stuck right up against it. You'll tend to get better balance in that situation. All of the other things apply that apply in large rooms, in terms of toe-in, how far apart the speakers are, and so on. You can look into our previous video recommendations on those set up points.

One of the other things you're going to find in a small room is that you may be limited a little bit in the soundstage size, so when it comes to things like toe-in, you may want to actually toe the speakers in a little bit less than you would in a larger listening environment. In some cases, having the speakers firing straight ahead will actually give you a better sense of space in a small room.

Elevating Speakers:  We had a question from one of our message board members asking when you might want to raise the level of speakers off the floor slightly: floorstanders and subwoofers. There are only two cases where I would attempt that with Floorstanding speakers. One of them is if you've got an extremely high or extremely low listening seat, and you can't seem to get good balance, because you're way off the vertical balance of the high frequency drivers of the loudspeaker. In that case, you can try raising the speaker up a little bit, or ideally if you can, modify the listening position further away from the speaker.

What will happen if you actually raise a floorstanding speaker up off the floor is you'll change what's called the floor bounce, which has a huge impact on the mid-bass response of the speaker. When we design a speaker and doing the listen test we assume that the floor is where it is: right below the bottom of the cabinet. As soon as you raise it, you're going to modify that floor bounce and get somewhat unpredictable results.

I'm not saying that you shouldn't try it, and in some cases it's going to work well, but it's not something I'd recommend for a typical setup.

Subwoofers: same thing applies. The lower that woofer can be and the closer to the floor it can be, the better coupling to the room you're going to get. So overall I wouldn't recommend changing the height of those speakers, and with subwoofers most of the frequencies are omnidirectional anyway so having it fire closer to ear level isn't really going to help anything, it's just modifying the interaction of the subwoofer with the room.

Did we miss anything that you wanted to cover? Reach out to us on the Axiom Message Boards and let us know! We'll be happy to answer your questions or record more videos on this topic.

We've got an M80 High-Powered floorstanding speaker here in the video so you can get some ideas of what goes on in the room - how it interacts with the loudspeaker - and some simple tips that you can use when you're first setting up your speakers to try and get the best out of them.

Unfortunately speakers have a very complex interaction with rooms. At low frequencies the performance is determined by the overall dimensions of the room: height, width and depth. This influences something called standing waves. We also deal with boundary effects or boundary loading, which is the proximity of the speaker to the floor, the back wall, the ceiling and side walls.

At mid and high frequencies, we start looking at reflections. The reflections will depend on where the speakers are positioned in the room, and in particular how closely they are positioned to the sidewall will determine major sidewall reflections. Also the material that is on the wall and your floors - whether it's carpeted or it's a hard surface like hardwood, and also the absorptive and reflective items you have in your room - couches, chairs, bookcases, tables - all of those things influence what the speaker is going to perform like in the room. As you can imagine, every room is different, just like every loudspeaker is different, so there aren't any cut-and-dried "Do this and your speaker will work perfectly" rules.

But here's a few things that you can look at.

One of the things we want to do ideally is to keep the speaker away from the major wall boundaries. So that's the rear wall and the side wall. Those will influence how much boundary loading (that is, how much pickup you have in the bass) which can lead to the speaker being boomy-sounding or overblown in the bass if the speaker is too close to those boundaries.

In many setups you don't have the luxury of getting the boundary away from the rear wall or side walls. In those cases you might want to look at port plugs, just as we talked about in the bookshelf speakers. This takes experimentation in your room: whether you plug one of the rear ports, both of the rear ports (or however many ports the speaker has) etc. It's something you can adjust and play with to get better bottom-end balance if you use port plugs and the speaker's got to be very close to the rear wall or side wall.

Now, in terms of how far apart your speakers should be, a basic guideline is to equilateral triangle when you first set up the speakers. The two speakers form two of the corners of the triangle, and the third corner is your main listening position. So let's say that the distance from your listening position to the speaker is 10 feet. Try to start with the speakers 10 feet apart from one another. To many people, this is going to seem like having the speakers way too far apart. If you're 15 feet away from the speakers for example, 15 feet of separation will seem like way too much. But try it: start at that point if you can (assuming your room is wide enough) and have a listen. What you're looking for is good definition of the center image. If the image is washed out and you get a wall of sound, meaning you can't focus anything between the speakers, start moving them now closer together to one another until that locks in.

What's happening? The wider apart you have your speakers positioned, the wider the soundstage and the image is going to be. But if it gets too wide you're going to lose that image focus - for example, centering things like solo vocalists between the speakers. So you want a balance between the two.

One of the other things we can play with is toe-in. Toe-in simply is angling the speakers slightly towards your main listening position. IF I have a speaker that is firing straight forward (straight to the back and front walls and perpendicular to the side walls) that is a speaker that has zero toe-in. What you tend to get in this configuration is a washed-out image if the speaker is facing straight forward. So what you want to try doing in small increments is angling the speaker so that those drivers on the front baffle are starting to fire more directly at your listening position.

Again, this is something that you have to play with. At some point if the speakers are toed in way too much, you'll get very very tight image focus, but you'll lose any sense of space and proportion. So you really have to play with that sort of adjustment. When I'm setting up speakers for the first time in a new room, I toe the speakers in so that I can just barely eyeball the side edge of the cabinet when I'm sitting at the listening position. Then I start playing: both toeing in further, and toeing out from that position, in 5-degree increments, to see where I get the best balance of the size and proportion of the soundstage and the center image.

So there's a few things that you can try that are very simple, and even if you've had your setup sounding great for years, you may want to try a few of these things out. There really isn't a way (unless you get very lucky) to just plunk a pair of floorstanding speakers down in your room and have them perform perfectly. Enjoy the experimenting!

Ian Colquhoun:  The M100 is quite large and contains three 6.5-inch high powered drivers.  The whole goal behind this product came from the return to stereo out there.   We're finding with a lot of our customers are looking for very high-powered, natural-sounding stereo pairs of speakers with large soundstages.

The M100 has been in development for four or five years now. Over that period of time, Andrew has developed a new woofer and a new tweeter, which were both a part of this project. We've found that people are returning to two-channel systems and sometimes using just two speakers in a very large space. We wanted to make sure that people could play these loudspeakers loud and clean, use big amplification, and have no compression happening in the bass whatsoever.

Andrew Welker: We started with what was then our flagship the M80, which has been around since the mid 90s. That's not a speaker we ever looked at as having any sort of limitation. It has good frequency response, good extension, sounds great, can play loud . . . there really weren't any major identifiable issues. But in most applications, our customers were using M80s in the context of a home theater system with a subwoofer.

When you take a subwoofer out of the equation, now extension and linear extension, particularly at very low frequencies, becomes something that you are looking for. You need to have good dynamic capability at those low frequencies to really give you the sense that you've got full bottom-end, full frequency range, and you're not losing anything - especially at high levels.

So we took our existing drive units and said

"What do we need to do to get this dynamic capability and this extension right to the very bottom end of the usable frequency response?"

There were two major things we needed to address. The first one was the newly redesigned woofer, which is available in high-powered versions for the M60 and M80 as well. It's a woofer with a larger voice coil. It's got a larger roll surround, which means there is more linear excursion capability, and it can handle far more amplifier power than the existing M80 can.

Now that's not to say the M80 is any slouch! But if you're going to be running high levels right down to 30Hz or 25Hz, you need that power handling capability.

The other thing that we've got to remember is that if you're only going to have two loudspeakers carrying the full range, if you've got really high dynamics, you're not splitting that output level between five or seven speakers and a subwoofer anymore - you have to get that out of two speakers. So in large spaces you have to run more power through the speakers to get that satisfying dynamic level up. In the tweeter to deal with power handling, we've gone to a die-cast faceplate assembly. The old one was plastic. That's actually significantly increased the power handling capability of the tweeter due to the cooling: we're actually using the faceplate as a heat synch.

The other thing to remember is that in very large systems, you naturally get a very large soundstage. You're surrounded with loudspeakers. In two-channel, you're depending very much on those two speakers and the quality of the recording that you're listening to.

One of the things we started really paying attention to a number of years ago was something called the listening window and the sound power. And really these things just talk about what we call the family of curves, which is how the speaker behaves from a frequency response standpoint if you measure all the way around the cabinet - so at any point.

Look at this graph. It shows the purple curve on top is the listening curve of the M100, and the green curve on the bottom is the sound power. Now the listening window is simply average that takes into account +/- 45 degrees from the on-axis frequency response of the speaker, and creates an average. That gives you an indication of what your perceived tonal balance of the speaker is going to be in a room. You don't any major discontinuities: you want it to be nice and smooth.

Similarly, the sound power takes into account the entire reflected energy that's going to be in the room, combined with that listening window signal. Again, you want it to be smooth with no discontinuities. That's very nice from a technical standpoint, but what does it mean in terms of of the performance of the speaker?

What it really means is the better the listening window and the sound power can be in terms of smoothness, you get a wider, more enveloping sound stage, you get better imaging, and really now you have two speakers that not only seem to disappear into the recording, but they actually fill the space. That's really important in a two channel set-up.

So there's a few of the things that we endeavored to do with the M100. We've started to trickle down the developments into the other models, but the M100 is really an ultimate statement of a true full-range speaker that is perfectly suited to two-channel reproduction.

Ian Colquhoun: Just in closing, we now have a complete line of these high-powered tower loudspeakers which are designed specifically for stereo reproduction: M60, M80 and of course the M100.

The M100 is a perfect match for the ADA 1500 amplifier, which in a two-channel configuration into the 4-ohm load of the M100, can deliver 750 watts per channel. This is a speaker that loves that kind of power, and the package gives you the ultimate two-channel system.

In a recent post on our message boards, Message Board Member Eggman asked "Would you happen to know if Axiom makes all their speaker parts in-house? Just curious."

It's a great question, and it was followed up by MichaelTrottar asking "is that for a better sound quality...?"

There are two main reasons for manufacturing our own parts: sound quality and consistency.

The sound quality is achieved by having more options available to us when designing the finished product. If you are selecting your drivers from already available parts then you only have the crossover and the cabinet as variables that you can completely control in the design process. This will put limitations on how refined you can make your family of curves (assuming you have the facility to measure them at all). The family of curves is by far and away the thing that affects the sound quality of your finished product the most. The family of curves refers to all the amplitude response curves taken in a sphere around the loudspeaker in an anechoic environment and the various averages built from all these response curves. And finally the interpretation of all of these curves and averages which needs to be determined using Double Blind Listen Testing.

Consistency of the acoustical measurements of each part manufactured is what guarantees that every finished product you make is exactly like the original design reference. Without this there is really no point to spending a lot of time refining your original design. Consistency of the end acoustical measurement of each part in driver manufacturing is not an easy thing to achieve. Manufacturing our own drivers allows us to batch manufacture them as opposed to the usual assembly line. Batch manufacturing means that we can test each batch for acoustical consistency and never have thousands of drive units either finished or partly finished before doing a full suite of acoustical tests.

One of the things that we talked about in the last video was to try to get speakers mounted in a cabinet or a bookshelf as close to ear level as possible. But there's always going to be some situations where you don't have the luxury of doing that. In the case where you've got to have the speaker on a low shelf or the center channel on a low shelf in a cabinet, what you want to do is have the speaker tilted upward so that it is firing at ear level. One of the members of our forums actually tried this out on his center channel and found that he got an improvement in clarity when he made the change.

Axiom center channels can actually be ordered to have the angled section on the bottom of the speaker instead of top, which will have the speaker naturally sitting up at an angle. If, however, you've already ordered your center channel and you're changing your set up or installation, you can easily buy something like a rubber doorstop to help angle the speaker up. My brother-in-law actually uses hockey pucks for this which also works well.

Now, one of the things I address in the last video was should we be concerned about the fact that the speaker is sitting right on a shelf? All of Axiom's small speakers - bookshelf and centers - come with some small, clear, rubber self-adhesive bumpers. These should definitely be installed if you are going to be placing the speakers directly on a shelf. The reason is that by installing four of these bumpers, you've got four small contact points to the shelf which will minimize the amount of vibration that's transferred into the shelving unit and into your cabinet, and prevent it from rattling items that you have there.

There was also a case where the speaker couldn't be placed right at ear level, and we suggested that you put it slightly above ear level. Now, what happens if you have to put the speaker in a high shelf, or you're mounting it high on the wall? You want to do the same thing as when it's only in a low position, only in reverse: you want to tilt the speaker downwards towards ear level. If you use something like our Full Metal Bracket to mount the speaker to the wall, you have a range of adjustment built in, so you can adjust the angle to get that position so that it's firing at ear height.

If you don't wall-mount and you're going to be putting it in a cabinet, angle the back of the speaker up so that it is tilted down toward the listening position.

Now, there is one other instance where you've got a shelf opening that doesn't allow you to have your bookshelf speaker oriented vertically (incidentally, we prefer it to be vertical because of the horizontal dispersion. If you put the speaker on its side, that now becomes the vertical dispersion of the speaker and forces what was the vertical to become the horizontal. What does that mean? You won't get as smooth a response off-axis.) There are some cases where you can't help that and you are forced to put the speaker on its side. Again, because of the shape of the Axiom speaker cabinets, that will actually angle the driver array upwards slightly. If you don't want that, apply the doorstop or hockey pucks or whatever you choose to make the dispersion more even.

Now, people often ask "If I have to put the speakers on their sides, should the tweeters be on the inside or the outside?" That's going to be something you have to try out in both positions to see how it works. Generally, if the speakers are very close to the side walls, you're going to want the tweeters on the outside. That's just because of the way the reflections - the reflected information or sounds - is going to reach the listening position. But this is purely trial-and-error. You should try it in both orientations to see which one sounds smoother and better to you.

Hopefully that gives you a few more tricks that you can apply to your setup that should result in improved sound quality!

With Super Bowl almost upon us, and March Madness (basketball) barely one month off, the best way to deal with the winter (if you're in the north-east or mid-west of the US and much of Canada) is to cocoon at home with a great home theater system and a big screen TV. Even for a non-sporting type like me, the High Definition excitement of men's college basketball or football on a large screen has won me over, especially when football games are played in those outdoor stadiums in warm, sunny locations.

In these economically tough times, prices for Blu-ray hd players and large flat-screen TVs have come down dramatically, so an upgrade to a first-rate surround speaker system like Axiom, a Blu-ray player, HDTV display or a new AV receiver can be had for less than a couple of plane fares to a Caribbean or Mexican vacation. Look at it this way: sure, the warmth and beaches are nice for a week, but then the money is gone and you're back in the cold. Take the same funds and apply them to a new Axiom 5.1-channel surround system, or a large flat-screen LCD or plasma TV or AV receiver, and you'll have many years of enjoying great sound reproduction and Hi-Def images.

I've heard that Blu ray HD Players are expensive and have glitches.

Two years ago, that was true. Not anymore. The latest name-brand Blu-ray players (Panasonic, Samsung, and Sony) are available for $300 or less, and the glitches—agonizingly slow loading times of 1 or 2 minutes—have been fixed: these players typically load Blu-ray discs in 20 seconds or less.

My current DVD player up-converts to 1080p, which is HD, so why do I need Blu-ray?

Standard DVDs are Standard Definition (SD), and no matter how much de-interlacing and scaling (up converting) takes place, the resulting image still isn't High Definition (HD). It's a mathematically interpolated version of HD-- good, yes, but not true HD. Blu-ray discs are HD, and the purity of color rendition and detail expose standard DVDs for what they are---good, but not great. We're already watching true HD from cable and satellite services, as well as over-the-air by antenna. It only makes sense to move to the disc format of High Definition—Blu-ray.

My HDTV is just 720p. New flat-panel LCD or plasma TVs seem to be 1080p, which is what Blu-ray discs are. So what's the point of getting a new Blu-ray player if my TV can only display 720p?

Dolby Digital and dts 5.1-channel soundtracks from Standard DVDs sound pretty good to me. Aren't the Blu-ray soundtracks the same?

Dolby Digital and dts soundtracks are remarkably good sounding, but they are lossy, and although the data losses are nowhere near as great as typical MP3 or i-Pod downloads, they still exist. This means a certain amount of data is thrown away in order to compress six channels of sound into the available space on a standard DVD. Blu-ray soundtracks are quite different: Dolby TruHD and dts-HD Master Audio are lossless soundtracks that are identical copies of a movie's master soundtracks when they are decoded. Only Blu-ray has the capacity to contain these. This is particularly good news for us here at Axiom, since we specialize in making products capable of letting you experience the huge dynamic range, more powerful bass, greater treble nuances, and essentially perfect fidelity to the original soundtrack mixes found on Blu-ray.

But my AV receiver only has standard Dolby Digital and dts decoding. I can't benefit from the new lossless Dolby TruHD or dts Blu-ray soundtracks.

Not necessarily. For quite a few years now, all but the least expensive AV receivers are equipped with a set of multi-channel analog inputs, typically a set of six or 8 RCA input jacks. If your AV receiver is so equipped, you only need find a Blu-ray player with internal decoding of Dolby TruHD and dts-HD Master Audio soundtracks. The Blu-ray player must also have a set of multi-channel analog outputs (not all do) that let you connect the decoded 5.1 or 7.1-channel RCA cable set to your AV receiver's multi-channel analog input set. The latter set of inputs keeps your AV receiver from becoming obsolete so long as the Blu ray hd player has the required 5.1 or 7.1 analog output set and internal decoding of Dolby TruHD and dts-HD Master Audio.

My AV receiver doesn't have HDMI inputs so I can't connect a Blu-ray player.

Yes, you very likely can. Virtually all HDTV video displays have one or more HDMI inputs, so you can bypass your AV receiver and connect the Blu-ray player's HDMI output directly to your TV's HDMI input, using the TV's source selector to choose the HDMI input when you want to watch Blu-ray discs. So you'll still benefit from the upgraded Blu-ray disc's video quality. However, you'll need to get a Blu-ray player with internal Dolby TruHD or dts-HD Master Audio decoding and analog multi-channel outputs in order to benefit from the high-resolution audio soundtracks.

My AV receiver has HDMI inputs and does something called “PCM” decoding, but it doesn't have its own Dolby TruHD or dts-HD Master Audio decoding. How do I get the improved soundtracks from a Blu-ray player?

You'd need to set the Blu-ray player to stream multi-channel PCM (Pulse Code Modulation) over its HDMI connection to your AV receiver, which will then sort out the 5.1 or 7.1-channel soundtracks. As long as your AV receiver has PCM decoding from an HDMI connection, then you'll be able to derive full benefit from the upgraded high-resolution soundtracks that the Blu-ray player decodes and sends via PCM over HDMI.

I have an older AV receiver that has only standard Dolby Digital or dts soundtrack decoding and no HDMI inputs. I did get a new HDTV, however. Can I still upgrade to a Blu-ray player?

As long as your new HDTV video display has an HDMI input, then you can connect the Blu-ray player's HDMI output directly to the TV and enjoy the HD video quality that Blu-ray discs deliver. Even if your AV receiver lacks a multi-channel analog input set, you could still get a standard Dolby Digital “legacy” soundtrack from the Blu-ray player's optical or coaxial digital audio output. All Blu-ray players must be able to output a standard legacy Dolby Digital or dts 5.1-channel soundtrack that is contained within the data stream on Blu-ray discs. You already know that Dolby Digital and dts soundtracks sound good, so you can use those until such time as you want to update your AV receiver to one with HDMI inputs and Dolby TruHD or dts-HD Master Audio capability.

I've heard that Blu-ray playback has extra features that you can sometimes access. What is that called?

Among Blu-ray's many capabilities is something called “BD Live,” which some Blu-ray discs have and which will unlock extra features online when you are connected to the Internet and have a “Profile 2.0” Blu-ray player. Profile 2.0 compatibility enables on-screen video commentaries, picture-in-picture, and networking capabilities. Note too that BD Live-enhanced discs also tend to have slower loading times. If you don't need those extras, Blu-ray hd players with Profile 1.1 or 1.0 will still play back high-definition Blu-ray discs, but without the special picture-in-picture commentary and networking abilities.

My standard DVD player has excellent up-converting capabilities to 1080p. Why should I give that up for a new Blu-ray hd player and its unknown deinterlacing and scaling abilities?

Well, of course, you don't have to. You can leave your current DVD player connected and add a Blu-ray player if you have enough inputs and source switching to accommodate both machines. However, what most of the new Blu-ray players possess is highly sophisticated internal scaling and deinterlacing, so that standard DVDs will look first-rate played on the new Blu-ray player. In this regard, it's still worthwhile checking out test reports in magazines and on-line on new Blu-ray players' upconverting abilities, as there are performance differences from brand to brand.

Isn't optical disc storage of movies on DVD or Blu-ray just a stopgap measure? Why should I get a new Blu-ray player when streaming of HD movies over the Internet is already being offered?

It's true that Netflix offers streaming of HD movies if you have a Blu-ray player with the ability to connect to the Internet and receive Netflix-streamed movies. However, so far, results and video quality are variable, partly because of the huge bandwidth required for HD video and high-rez audio soundtracks. In the future, of course, when every household is connected via fiber optic cable with its very fast and large data capacity, then streaming of HD content will become practical. There's still the convenience factor of disc storage—you can put it aside to watch anytime you choose, and there's an enormous range of entertainment already on DVD; admittedly fewer releases on Blu-ray, but the release list is growing each month.

The aforementioned cover most of the queries about Blu-ray. Doubtless, there are questions I may have overlooked. Blu-ray is still relatively young, but the format war has been settled and eventually most of us will step on-board.

If you have further inquiries about blu ray hd players, visit Axiom's Forums for detailed help or e-mail us.

Today we're going to start off with some basics of bookshelves and center channels. One of the biggest mistakes people make when they place a bookshelf speaker or center channel on a shelf is that they bury them in the cabinet. A lot of times this is for aesthetic reasons, but acoustically it's pretty much one of the worst things that you can do.

What will happen with a speaker even an inch or two behind the front edge of the shelf, it will create reflections that will muffle the sound or destroy the image. You'll get a very colored sound quality from your center channel or your bookshelf speaker.

What you want to do is make sure the speaker is sitting as flush as possible or proud of the front edge of the shelf in the cabinet. This will give you far better acoustic performance.

In a previous video we talked about port plugs when you've got a speaker like this M3 which has a rear port. You're going to get bass-loading from the cabinet volume behind the actual loudspeaker cabinet. If you think about it, the space in between the shelves is actually acting as another cabinet that interacts with the port on the back of the speaker. In that case you can either experiment with stuffing something in the port, or purchasing a pair of our port plugs, which will give you much smoother bass response in this position.

One of the questions that was asked by one of our forum members was about height when you're positioning a bookshelf speaker or a center channel on a shelf. We tend to want loudspeakers to be at ear level, and that's always going to be the ideal. However, in many cases that's not practical for the cabinet or shelving that you have, and in the case of center channels, that would probably put the speaker right in the center of your line of sight to the television, and obviously that's no good! Now, if you need to make a compromise and move the speaker above or below ear level, then in my experience moving the speaker above typical ear level will result in a more natural soundstage and image, compared to putting the speaker lower down. Part of this is the fact that the speaker is now going to be reflecting and have some absorption from the furniture and other materials that are in the room that are typically lower down in level and closer to the floor. So that's one thing: if you can, try and get the speakers at ear level, and if not, slightly above ear level.

That also applies to center channels. The convention for center channels is to typically put them in the cabinet that is below the screen, because the cabinet is holding the television set. But if you have the opportunity and a cabinet that has shelving above your television screen, trying putting the center up there. You may be surprised to find out that there's quite an improvement in sound quality by doing that.

One of the other things that I want to mention is the actual center channel set up itself. In the context of a whole home theater system, ideally set the front speakers up first as a stereo pair. Get them positioned and sounding the way that you want, and then integrate the center channel in to the system. Many times what will happen is that the center channel will actually fill out the soundstage between the left and right speaker: that's technically what it's supposed to do. So by getting the front main speakers sounding the way they should be sounding, it's a lot easier then to integrate the center channel into that.

One other thing: I'm not a big fan of the automatic set-up systems and room correction systems that are found in many home theater receivers. If you're going to use one of those auto set-ups, go back and set the sound for the center channels one or two dB lower than what the auto correction system has given you. What I normally find is that center channel levels are set far too high relative to the front left and rights, which makes the center channel stick out audibly, so that it sounds like it's more forward audibly than the front left-and right channels, which is not what you want. You want an arc of immersive sound that blends also with the image that you're seeing on the screen.

So there are a few simple things that you can try with the set up of your system. We'll be doing more in future videos. Don't forget to post your suggestions!

There are a number of reasons why you might want to use these, and they are going to be offered on the website as an accessory, so I'll also cover where you might want to use these other than for the model M100.

When you place a loudspeaker in a room, if it has to be close to anything called a room boundary (back walls, side walls), you get something called boundary reinforcement happening. Boundary reinforcement will tend to accentuate the mid-bass frequencies. In a speaker like the M100 that has very good low frequency extension and output capabilities, you can easily end up with 'too much of a good thing' in those environments. And if you're in a small listening room or environment, you can find that because everything is closer to the boundaries that you'll also get that midbass accentuation, which can be too much of a good thing and can actually make things sound really slow and congested.

For this reason, we've supplied port plugs with the M100. We suggest that you set up and listen to the speaker as-is without any of the plugs in place for a week or two, and then add one plug at a time (in the M100 we suggest adding them in the bottom three rear ports), and every time you add a plug, listen for a few days again, and listen for how the bass character changes. This is something that is very room dependent and also dependent on your personal listening tastes. Some people may like that bass accentuation. There's no right or wrong answer as to whether you should use the port plugs, but they are there as an option if you find the speaker has too much mid-bass.

Now I mentioned earlier that we're going to be offering these port plugs on the website, and there are a couple of other situations where you may want to look at using them. If you purchase one of our bookshelf models like the M22, M3 or M2, they all have rear ports. If you plan on mounting the speakers on our Full Metal Bracket, up on a wall, again now it's sitting next to a boundary, so it has that same reinforcement. In that case, you might want to try using the port plugs to plug those rear ports. It might give you smoother bass response.

Also, if you're going to be putting a bookshelf speaker on a bookshelf or in a cabinet of some sort, you get the same sort of boundary gain in the mid-bass frequencies. That's another case where you might want to look at buying a couple of port plugs and trying them out. It just might give you a smoother and more linear sound quality.

Don't worry - we've got you covered!  Just print out this handy 5.1 Audiophile and Movie Buff Gift Guide, circle the one you really want, and leave it out conspicuously!  You're sure to get something you love this year.

1.  The Beatles In Stereo Vinyl Box

Oh yes, you can have 14 albums in unscratched glory, just like when you first brought them home!  This collection includes a 252 page hardcover book to pour over while you're listening to the Abbey Road Remastered editions of The White Album, Sgt. Pepper's Lonely Heart Club Band and more!  If someone special on your list has recently rediscovered the pleasures of long listening sessions in stereo glory, this set might be the perfect gift.  Price from www.TheBeatles.com - $450.

2.  Samsung UN65F9000 Television

If you've been waiting for an Ultra HD 4K television set so you can brag that you have 4 times the quality of 1080p HD, then this might just be the set for you.  An internet-connected, pop-up camera-enabled, gesture-controlled marvel that comes complete with voice recognition software and a quad-core processor, you'll be sure to have plenty to do after the turkey wears off just trying to figure out all the new features.   Street price  - $5,000.

3.  Xbox One

Why would an audiophile need another gaming console?  Well, if you still have a first-generation console in your system, you'll be thrilled with all the changes available from the latest boxes.  The big question on most people's minds this season is whether to  upgrade to the  Xbox One or Playstation 4, and the answer for home theater and music lovers is clear:  PS4 only allows integration with its clunky, proprietary Music Unlimited System.  Xbox One, on the other hand, has MP3 support, DLNA (Digital Living Network Alliance®) streaming, audio CDs, and a clear desire to become your family's media hub.  Price at launch:  $499.

4. Logitech Harmony Smart Control

Let's face it - your smart phone is probably always by your side these days.  Why sacrifice valuable coffee table space for yet another remote control when you can download this easy-to-use app for your iPhone or Android device?  The Harmony Hub receives wi-fi signals from  your phone and converts them to IR and Bluetooth signals that will power your home theater system.  Launch your media center, watch the latest flick in HD from your Netflix account, control the volume - all from your phone.  Price from Logitech: $129.99

5.  Omnidirectional Speakers

We know, we know, we're biased - but if the reactions of any of the numerous guests we've had through our World Headquarters in Dwight are any indication, we're not the only ones who have become completely seduced by the 3-D soundstage produced by these front-and-rear-driver'd speakers.  If you've made the move to 3-D TV, or if you're rediscovering the pleasures of an afternoon of listening to all your favourite music, then hearing it on these speakers will transform your listening experience the way your very first album did: expect to feel wonder, awe, and a sense of coolness that belies description.  Available in the 11-driver LFR1100 configuration, 10-driver LFR880 or the six-driver LFR660 configuration, this award-winning speaker had Digital Trends enthusing:

"the LFR-1100s' massive soundstage and vibrant power also make them the perfect system for large gatherings of folks who actually care about the sound - no more fighting over that sweet spot. (Audiophile party anyone?) If you're looking to step into a real home hi-fi system, we think purchasing the Axiom LFR-1100 and ADA-1500-4 is an investment you will never regret." --Ryan Waniata , Digital Trends

.1  Han Solo Fridge

It wouldn't be an Axiom List without a .1, so for the whimsical Star Wars fan in your life, why not pick up the Hans Solo fridge?  First spotted online in the very amusing BT3A refrigerator challenge, this so-far-just-a-dream fridge of Han Solo frozen in carbonite is a way cooler addition to your home theater's snack bar than a Skyways Airmail Catalog popcorn machine!

There you have it: the top 5.1 gifts for the home theater lover on your list!

Did we miss any must-haves?  Anything hot on your list?  Weigh in in the comments below!

As many of you know the LFR1100 is omnidirectional, and that just means it radiates sound in 360 degrees - in all directions. To achieve that, there is a complement of drive units - two midranges and two tweeters - on the back. Because of that, the relative placement of the LFR1100 to the back wall, and the angle at which you've got it to the back wall, influences the soundstage, and the way that the sound is going to blend at the listening position.

So one of the things that we recommend - if at all possible - is to allow a couple of feet from the rear of the speaker to the back wall. In this setup here, it's about 2 feet. If however you need to get the speaker closer than that, there is a boundary compensation switch on the back of the unit.

Now, there's no hard-and fast rule of exactly when that switch needs to be used. You've just got to experiment and listen: is the sound big and full, or when you move the speakers back in position, does the soundstage collapse and sound more like a conventional loudspeaker? You want it to sound big and open and spacious.

Another thing to note: even though the back of the speaker is angled so that you don't have to angle the speaker towards the listening position much, I find that in most situations that actually toeing the speaker in towards and aiming it towards the listening position a little bit helps to get that reflected information out from behind the speaker to give you that enveloping soundstage.

If you have one of the latest LFR models, the 880 or the smaller 660, neither of those have the angled back. In that case, toe-in is extremely important, because if the speakers are just pointing straight, then the reflection from behind it won't escape and will just bounce around behind it. So make sure that you toe the speakers in towards the listening position to get a nice seamless soundstage.

Ian Colquhoun: In follow up to Andrew's discussion of the placement of the speaker in a room for an LFR1100 or 660 or 880, I thought I'd get into a bit about how the electronics work.

For these three models, the LFR series, the rear channel is separated from the front channel by this digital signal processor, so it requires four channels of amplification to drive one pair of loudspeakers. What I've got here is the DSP box sitting on top of an ADA 1500 amplifier. This particular DSP is the top-of-line pre-amp model of DSP (there is now going to be four models) and here you have either XLR or RCA inputs, a set of left channel front and rear output (either XLR or RCA) and the right side over here, into the four-channel ADA 1500 amplifier, and there are two sets of speaker wires going to each speaker: one for the front and one for the rear. Here is where you would see your input from your pre-amplifier.

ADA 1500 Amplifier and DSP Unit

For other models of this digital signal processor, there are no XLR connectors, but you now have a choice between an either an RCA input or a high-level input. So if you're using a processor that does not have pre-amplifier outputs, you're still able to run any of the processors in the LFR series. You would simply take your speaker wires from the receiver for the front right and left and go into the high level (or if you do have pre-outs go in to the RCA and then out of the RCAs into the amplifier - either an ADA 1250 or ADA 1500). And then the four channels come  out to the two speakers.

Then there's another model which combines our ADA 1000 amplifier with the DSP. So in that particular case, you would come in from your into the receiver either using line-level pre-outs or the speaker outputs for right and left channel, directly into the one unit. It has the amplifier in it and four channels of amplification coming out. So it's a convenient all-in-one unit.

In the fourth model, it works similarly except that it also contains a preamp. So now there are three selectable input sources and four channels of amplification out. And there's a volume, balance control, and input selector on the front. So now all you need to do is hook any source to the DSP/Amp combination, go right to the speakers, and you're done.

So I hope that helps explain how this works: it seems a little complicated at first but it's simply taking two channels in and separating it into four channels so that we have a front-rear, front-rear for each speaker.

Lastly I think I should just mention the Boundary switch. Andrew mentioned it in his discussion. It's located here and it's on four models. It's Boundary Compensation "on" and "off" and if you are getting close to the wall in your set up you should turn it on. But there's nothing wrong with experimenting no matter where your speakers are located, don't forget - try it on and off to see what works best in your room set up.

Andrew Welker: Previously we've done a video showing you different adjustments and connections that are available on our subwoofer amplifiers. We decided today to shoot a video in the Axiom Electronic Prototyping Lab (you can see all the components behind us in the small containers).

We wanted to talk about the part of the subwoofer amplifier that you don't see, because from the outside, most amplifiers look pretty similar between different companies. It's a flat piece of metal. Sometimes there will be a heat sink, sometimes there won't be, but basically they're all rectangular or square plates on the back of the subwoofer.

That's important because it's the interface that you, the customer, has for making connections and adjustments to your subwoofer. But the real 'meat' of the amplifier is going on in the inside, and it's on the inside - unfortunately the part you can't see - that tells us a lot about the quality of the amplifier and where your money is going.

All Axiom amplifiers, whether they be subwoofer amplifiers or stand-alone amplifiers, use something called a linear power supply. All that means is that it is a fairly old-school large toroidal power transformer and large filter capacitors.

If you look at many amplifiers for subwoofers that are on the market now, they use something called a switching power supply. They're much less bulky and and much lighter, and in many ways they're more efficient (at least in standby), but one of the reasons we use a linear power supply instead is because frankly, it sounds a lot better! You have better dynamic capability, better headroom, and a linear power supply can respond to current demands much more quickly than a switching power supply.

One of the other things that many people don't realize is that switching power supplies don't have a very long life in general. If anything goes wrong with most subwoofer amplifiers, it's usually the switching power supply. One of the things that tells the tale to the consumer is to look at any sub you're looking at buying, and checking out the warranty. The warranty for the amplifier should be the same lenght of time as the warranty for the whole subwoofer. In the case of Axiom's subwoofers, that's 5 years on everything. Many manufactures will only warranty the amplifier - the electronics portion - for only 1 year. You should wonder why the manufacturer doesn't have enough confidence to warranty the electronics for the same length of time as the loudspeaker, because frankly the amplifier should last as long as the rest of the subwoofer.

This is the reason we use a conventional linear power supply. A) because it sounds better and B) because it lasts longer.

Now, also at the heart of the amplifier is the amplifier board itself. All of the amplifiers in Axiom subwoofers are Class D or switching amplifiers. This is a class of amplifier that is very efficient. They run extremely cool, which is also important for longevity. Ours are completely designed and manufactured in-house.

One of the reasons that's important is many manufacturers are buying so-called plate amplifiers for their subwoofers off the shelf from some company that has designed the entire amplifier. One of the issues with this is you can never really guarantee every component that goes into the amplifier. This has some impact on longevity as well.

Every single component on our amplifier boards and DSP boards are sourced and supplied by us, and in terms of critical components they're actually sourced here in North America and then they are sent to our vendor for populating in Asia. Why is that important? It's another area where you want to have very tight control over the manufacturing of your product, because there are a lot of counterfeit parts out there and those can have a huge impact not only on the sound quality of your amplifier but also on how long it last.

Hopefully that gave you a little bit of background as to why our subwoofer amplifiers are more traditional in that they use one of these large transformers, and they're fairly heavy: it's all for quality and for making the subwoofer amplifier last.

Ian Colquhoun: Today I thought we'd talk about tweeter manufacturing and driver manufacturing. It was really brought about by a post on our forums by regular Socketman, who asked if we build our own drivers, particularly the tweeter, and where we made the tweeter. So I thought I'd clarify that a bit.

It prompted a talk between Andrew [Welker, Axiom Engineer], about doing a whole video on not just the tweeter and where and how it's made, but actually into the whole tweeter design. We ended up deciding we'd save that for a completely separate video, later in the fall. For now I'll just keep to the manufacturing itself.

There was a really big change in the manufacturing of drivers for Axiom in 2008. Prior to that we had the component parts made to order (so they were our designs, but not made at our factory). Some of them were made at our factory in Canada, and the rest were purchased on an OEM basis in China. Frankly, we were never really 100% happy with that. In fact, starting well before that in 2004, I started the process of forming a WOFE, a Wholly Owned Foreign Enterprise in China. It's a company that is 100% owned by our Canadian company. The idea was that we would set up and manufacture our own drivers in our own factory and to our own standards. It's called Axiom Audio Shanghai.

It took until 2006 to start manufacturing there and until 2008 to start producing our tweeters in our own factory ourselves. What follows is some still shots that I took earlier this year explaining the manufacturing.

The first shot shows a view to Motor Assembly.

Tweeter Motor Assembly

This is the T-yoke magnet and top-plate getting glued together. The yellow piece is a jig that holds it while the glue dries.

Voice Coil

The next shot is of a tweeter voice coil. The thing that's so interesting about this is that you'll notice that the actual voice coil lead is terminated right at the voice coil and a tinsel lead is soldered on at that point. This is very important for the longevity of a tweeter. It's quite common to just take the voice coil wire and extend it out across the terminal plate and solder it to the wire lug, but this is really fraught with problems and is probably going to fail over time. So we go to the expense of soldering on a tinsel lead so those lead wires don't break over time.

In the next shot, this is a jig that shows you how the voice coil is centered onto the t-yoke and top-plate assembly. I think what's unique about this since we took over our own manufacturing, is we were able to make our own jigs (we tooled them at a local machine shop here in Canada with a very very expensive CNC lathe) and we were able to make these jigs to extremely tight tolerances so that we could get the voice coil at exactly the same spot in every tweeter. Even beyond that, we make the tweeters in sets, so once that voice coil has been jigged in that top-plate and t-yoke, it stays with that top-plate and t-yoke until it's completed and tested and sent to Canada.

It's little details like this we were never able to achieve when we were buying products on an OEM basis. A typical OEM driver manufacturer really wants to produce thousands and thousands of parts down an assembly line, and they're not really willing to start working on what they may think is a 'ridiculous' quality level. But it was important to us and we wanted to take that extra step, because really in tweeter manufacturing it's not about the cost of the parts: there's the t-yokes, magnets, top-plates, diaphragms and face plates. They're reasonably small and they cost what they cost. We were already using a titanium dome, which is a fairly expensive dome. But really what it comes down to is the care and attention into making every single tweeter exactly as you want it, holding each one to a very tight tolerance. It's easier to do in woofers: in tweeters, it's a little more difficult. You really have to go these special lengths in order to accomplish that.

Tweeter sets being lined up.

In the next picture here, you can see the sets being lined up. Hu and Lai are actually lining up the magnets and all of their associated voice coils are sitting there. They're about to put the ferrofluid in. The ferrofluid is put in with a very expensive pump that we bought in the United States from Fluid Metering Inc, which allows us to put the ferrofluid in to fractions of a micro liter. Again, this is goign after the idea of excellent consistency.

Final Tweeters

This next shot is the final tweeters together with the faceplates on, ready for testing. They get tested in an insulated square box with a microphone on the bottom and foam piece on top, which is on a spring-loaded arm that lowers the tweeter into the box.

Listen Inc, the multi-testing tool.

The real magic, though, is this Listen Inc measuring device which is hooked to a computer. It will do a series of tests all in one burst-sweep to the tweeter, so it will do impedance, amplitude, buzz-and-rub, phase . . . and it will then present the results to the operator, with a Pass or a Fail. The Pass of Fail parameters were all written by Andrew here, to the tolerances we wanted to try and keep.

So that's really how an Axiom tweeter is made. We'll get into more how it is actually designed a little bit later in the fall in a video then.

Ian Colquhoun: Today we want to talk about the ‘family of curves’, a topic we feel is not discussed often enough. It’s a topic which is extremely important to the sound of a loudspeaker – it is about what you’re actually going to hear in a room and how we determine that. As for why it’s not talked about enough, I think there are two reasons:

1. There’s nothing visual about it. You can’t look at a product and say “Oh, this is going to have a particular family of curves” just by what the drivers look like, the cabinet looks like, or the components on a crossover look like. None of these things really tell you much of anything about the family of curves, so we tend to gravitate and talk about things that you can see. While that’s sensible on one hand, it doesn’t really get into the meat-and-potatoes about what makes a good-sounding loudspeaker vs a not-so-good sounding loudspeaker.
2. The other reason it’s not talked about that much is that a family of curves is not an easy thing to measure. There are a lot of curves involved, and you really have to have an anechoic chamber in order to take all of these curves. So it’s probably not talked about in a lot of cases because it’s probably not measured.

Even just looking at a simple loudspeaker – say a 2-way bookshelf speaker – you’re looking at over 150 curves in order to create the entire family of curves that you need to work with and manipulate in order to create what’s going to be the end product. You’ve got the curves of all the individual drivers, and then you’ve got the curves of the combined end product, and that’s going to give you +150 curves. Realistically, in the process of the loudspeaker design, you’re going to be doing those over and over again (at least a certain number of them.) You can really end up in a design with over 1,000 curves before you’re done. And that’s for a simple bookshelf speaker! If you get into a multi-driver tower, you can start multiplying that number by two, three – even four times. So it’s not a particularly easy thing to do and you need the proper tools to do it.

And then once it’s all done, you still have to interpret what these curves mean. They don’t have what you would call a ‘normal’ sort of visual. If you think about on-axis or a listening window curve, we’re used to just seeing something that’s reasonably linear across the bandwidth, then that represents a good frequency response. But there’s quite a bit more to it. I’m going to turn it over to Andrew now to explain a little bit more about the family of amplitude response curves.

The family of curves

Andrew Welker: I guess the first question is “What is the family of curves?” and what we’re looking at on the screen, is a whole bunch of curves – amplitude responses – measured here in the chamber. The speaker is measured at points all the way around the cabinet horizontally and then all the way around the cabinet vertically.

One of the questions people often ask is, “Why do I care what’s coming out of the bottom of the speaker or the back of the speaker when I can’t hear that?” There is a misconception that some people have that the sound comes out of the front of the speaker and that’s all we’re worried about. Well, that would be the case if we listened to speakers inside an environment like this, where there’s no reflections. That’s what an anechoic chamber is.

But when you put the speaker in a normal room — and it doesn’t matter how much damping, or padding, or furniture, or carpet, or whatever you have in the room — you get reflections. And those reflections are not predominantly the direct signal from the speaker, it’s all of these off-axis measurements, all these positions that cause reflections coming all the way around the speaker including behind it.

Even though there’s no drivers back there, the low frequencies will have an impact behind the cabinet, the cabinet itself can radiate some sound. So we have to measure, and have an idea what the speaker is going to do in the room. The best way to evaluate that is by looking at this family of curves.

Now, this is obviously a mess, and very difficult to interpret, if you just looked at it in this method with all of these curves overlaid on one another and it doesn’t tell you a heck of a lot. And if we looked at any of the individual curves, in isolation, it also doesn’t tell you a lot.

Many people think that you need the flat on-axis response. Well, that’s nice to have, assuming that the family of curves looks smooth and even too.

Now, how we interpret this mess of curves is by looking at two main curves that we call the listening window and the sound power. The listening window takes into account the direct signal from the speaker and what are known as the “first reflection points” off of the side walls, the floor, and the ceiling. And it averages those into this upper curve that you see.

The sound power is an average of all of those curves that were on the previous page and it’s the interpretation of how you do the averaging that really is the magic of loudspeaker design. Even though companies, like us, Paradigm, PSB, Harmon, have a foundation in the NRC research that first brought to light this idea of a listening window and a sound power. It’s the way that the averaging is done is really different between all the companies. That’s why all of our speakers sound a little bit different from one another’s.

Interpreting these curves we can understand everything that the loudspeaker is doing and how it’s going to interact with the room. Small changes that we bring to individual curves may or may not impact the listening window and the sound power.

We’re always adjusting things to make these two curves look a certain way, and really, smoothness is something that we’re looking for. We don’t want big discontinuities in either the listening window or the sound power, because that will suggest that there’s an issue with the way the crossover has been designed.

M80 Listening Window and Sound Power

LFR Listening Window and Sound Power

Now listening window and sound power, this is showing a forward radiating speaker like the M80 we have the computer sitting on here. But the interpretation changes depending on how the speaker radiates sound. So, as many of you are aware, we have a speaker called the LFR1100 which is an omni-directional speaker. We call it omni-directional because it radiates energy equally in all directions. And that’s accomplished by putting drive units on the back of the speaker.

Now, you’ll see here that whereas the sound power curve and the listening window (the listening window is still on top), the shape is different. It’s different simply because the speaker is radiating sound differently than the forward radiating speaker because we have that energy from the back. Now looking at these curves you’d say well is that good or is it not, because it looks different than the other sound power curves we saw in the previous page and here’s where again it becomes a matter of interpreting exactly what these curves should be looking like.

At the end of the day, all that really matters is that you have to consider all of these family of curves in trying to assess how the speaker is going to perform in the listening room, and that’s why we actually place more importance on this family of measurements than anything else that we do in a speaker design.

Ian: On this point of the omni directional speaker, if you tried to imagine a pure omni directional speaker, where no matter where you measured the speaker, it would have exactly the same amplitude response. Then technically you would end up with a sound power listening window on axis curve that were all exactly the same curve.

Then it creates a very interesting situation where the whole idea of what the listening window should look like – reasonably linear – and then the sound power curve that is sort of dropping by 8 or 10dB across the bandwidth. All of that is sort of out the window and of course, Andrew has vast experience in designing omni-directional speakers. It makes for quite an exciting challenge.

It is an important point about listening tests as well in that really, about 80% of the listening tests that we do here, the double-blind listening tests, are about the family of curves. We will make small adjustments to the family of curves, and subject that to a listening test, to see if we can isolate measurements that can improve the sound quality.

Probably, another topic for a video is about High Q versus Low Q, things that you see in these amplitude response curves, because Low Q stuff and amplitude response curves can be quite audible, and visually, very hard to see. So, I think that probably wraps up most of what we can say about the family of curves, other than to really reiterate that it’s not a topic that you can visually see when you look at a loudspeaker.

I think that if you looked at the history of our speakers, going back to 1980, and the family of curves in the original speakers, and what we knew about the family of curves then, it’s vastly different to what is being done today because this is where we are learning things all the time. So, even an M80 say, built in the mid 90’s, sounds different than one built 3 or 4 years later, and so on and so forth, and we give them new versions and as we get enough changes together. The real change is in this family of curves and what we’ve learned about it and how we’re able to improve it, all going back to the results from blind listening tests.

Andrew Welker: Ian recently made an announcement on the message boards about a new high-powered woofer for the LFR Omnidirectional Speaker and a new model that is going to be coming out shortly called an M100. He's asked me to explain what went into building the new woofer.

When we developed the LFR, which was the first system we did with three woofers, we got amazing reviews and incredible feedback. But we're always striving to improve things. One of the areas I started looking at was our 6.5"-woofer that we've been using for many years in our M80 and other speakers. There's always a number of areas that you can improve, and in a discussion with Ian I wanted to take the already-high power handling level of the woofers that we're using in the M80 and the LFR to another level. We thought it would be a good time to actually introduce that woofer in a brand new model called the M100.

The biggest change between the current 6.5-inch woofer and the new woofer is in the voice coil. This is really the element, along with the amplifier and the magnetic motor system of the woofer, this is what is doing the work to move the cone. The new voice coil is 1.5" in diameter rather than 1-inch like the current woofer. That means it's got more copper wire on it and it also has a larger aluminum former that the coil is wound on.

What that means is that coil can dissipate more heat, and heat is really the enemy when you're driving a woofer at high levels. Woofers and tweeters are naturally fairly inefficient: they only convert fractions of a percent (up to a couple percent in higher efficiency drivers) of the actual amplifier power energy into acoustic energy. The rest of that is lost in heat. So dissipating heat is very important and it's one of the reasons we increased the voice coil size for these new woofers.

Now the penalty of increasing the diameter and size of the voice coil is that the weight goes up. More weight means the woofer is going to have less output unless you compensate for it. The way you compensate for it is that you increase the magnetic strength of what's called the 'motor'.

The motor consists of three parts: one is called the top plate, then there is a ceramic permanent magnet, and then there is a t-yoke. Now, all of these parts are significantly larger than the previous 6.5"-woofer. This is simply to overcome the additional mass that we're dealing with in the larger voice coil.

Along with the bigger motor system and bigger voice coil, we wanted to increase what's called the xmax or the linear travel. That tells you how far the woofer can move up and down before it starts to come out of the magnetic field. As soon as that happens, the distortion goes way up, and you want to avoid that. So having as much linear excursion or xmax is always a good thing: it means you can drive the woofer harder with more power and not get high levels of distortion.

Part of that was achieved through the winding length of the voice coil – the amount of wire that's wound on the voice coil former. We were also faced with the limitation of how far the surround of our current cone would stretch. So even if we made the voice coil longer, we would get more travel, but it would stop at some point when the surround was stretched to its maximum. We've actually come up with a new surround that results in almost 30% more travel than the current surround that we're using.

So by changing the voice coil, we've improved power handling, we've improved the amount of linear excursion, and the new surround helps us to actually achieve that linear excursion without putting the brakes on.

One of the other things that we looked at is we went to a two-part epoxy glue a number of years ago for bonding the cone to the damper or a spider, and the spider to the voice coil, and this glue allows us to achieve far higher temperatures without a failure happening. Actually in these new high-powered woofers, we're essentially embedding both of these with glue, so there's two beads of glue, and what that allows us to do is really reduce the failure rate from a mechanical rate almost down to zero. Since we've made those changes to our subwoofer drivers we've had absolutely zero failures on those drivers.

You can see there are a number of areas where we have made improvements. At the end of the day, it just means the system will play even louder and cleaner before it starts making any noise from distortion. In the testing we've been doing on the LFR and M100 with these new woofers, we run out of amplifier power on an ADA1500 before the speaker gives up! So we've now got a system where there is really very little dynamic limitation and I think people will find it's a huge improvement.

Gourmet popcorn is the latest hot food trend, and with good reason. Nothing is easier to flavor and the choices are endless. When you have your own home theatre system, why settle for plastic packs of microwave popcorn for movie night snacks? Here are the top 10 hottest trends for you to make at home.

1. Ranch (It’s Not Just For Doritos®)

Ranch never seems to go out of style, it just keeps coming back again, and again. Take your favorite dry packet of ranch dip or dressing mix and sprinkle over a large bowl of freshly popped and buttered popcorn. If you want to make it a truly gourmet popcorn add some grated parmesan cheese.

Suggested Movie Pairing:  The Man From Snowy River  

2. Buffalo-Style (Faster Than Wings)

Chicken wings are great to eat while watching the game but for movie night snacks use those same great flavors on your popped treat. Melt butter and hot sauce (to taste) with a bit of honey, and use that to toss on a bowl of popcorn. If you want it hotter, add cayenne to the melted butter mix, since too much hot sauce will simply drown puffy kernels into a bedraggled soggy mush.

Suggested Movie Pairing:  Buffalo Bill  

3. Sriracha

This chili-and-garlic sauce is showing up in all kinds of gourmet dishes this year, and popcorn is probably the most surprising!  Mix 4 parts butter to 1 part sriracha and heat with a small amount of chopped garlic until the flavors have combined.  Eat this as soon as you've made it – otherwise, it will get soggy.

Suggested Movie Pairing:  The Impossible  

4. Caramel

For the simplest version of this gourmet popcorn, heat 1 part butter with 3 parts maple syrup and drizzle over. Or go all out and toss half your popcorn with caramel sauce, bake in a low 250º F oven until crisped, then break up the baked with your hands and toss with the unbaked half.

Suggested Movie Pairing:  Caramel  

5. Use Your Fave Ramen Packet

Ramen packets have been used for years now in sour cream for a quick chip dip, and if you love that, you’’ll love the flavor on your movie night snacks! Simply sprinkle the seasoning packet on a fresh bowl of buttered popcorn, and have endless variety from beef, chicken, and vegetable, to teriyaki, spicy, and kimchi versions.

Suggested Movie Pairing:  Godzilla – The Criterion-remastered version of the 1954 classic.  

6. Not-So-Gourmet Cheddar Cheese

Cheddar cheese is a great taste for movie night snacks, although it’’s too moist to work well on gourmet popcorn. You can easily buy a sprinkle that’’s cheese flavor, but the down n’’ dirty way is too use that mac & cheese packet (gasp).

Suggested Movie Pairing:  Showgirls  (Sorry – this is the cheesiest movie we could think of!)  

7. Chicago Style

One of those odd combos that sounds like it wouldn’’t work, but trust me, it does. Chicago style popcorn is cheese and caramel. Yup, that’s right, just combine 4 with 6, and you’’ve gone Chicago style.

Suggested Movie Pairing:  The Untouchables  

8. Truffle Butter

The foodies out there know truffle oil is not the real thing, but who would use the real thing on movie night snacks? To your melted butter add a little truffle oil and after tossing with your gourmet popcorn, use a little truffle salt instead of just plain salt.

Suggested Movie Pairing:  A Year In Provence  

9. Bacon

This is best made stovetop and using bacon fat instead of oil to pop your corn. Then you add to the bacon mix by finely grinding bacon bits and salt together, to sprinkle over the buttered popcorn. (This is another one that plays well with others for movie night snacks, caramel and bacon works spectacularly well together, and cheese with bacon is also stellar)

Suggested Movie Pairing:  Footloose, Kevin Bacon's classic 80s film  

10. Your Fave Flave

We’’ve all got one, fess up to yours. Whether it’’s smoked paprika, chilli powder, wasabi, sriracha, cinnamon sugar, or chocolate, you can easily adapt it to a gourmet popcorn sensation. If it’’s a dry spice, mix it with a little popcorn salt and sprinkle it over your buttered popcorn. If it’’s wet, like sriracha or chocolate, melt it with the butter. For lemon or lime seasoning, finely zest the peel and mix with your dry salt seasoning. Just go nuts! Speaking of nuts, you can always add peanuts, pecans, and walnuts, too.

There are your top 10 trends for making gourmet popcorn truly pop with flavor and fun. After all, you wouldn’t watch a movie with only the TV speakers on to give you sound <shudder>, so why would you buy pre-flavored, plastic packs of popcorn? You may even end up bringing your own seasoning creation to the movie theatre, not that I recommend it, but if you see me there with my own shaker, don’’t rat me out.

Suggested Movie Pairing:    This one is whatever your favorite is, of course!

Andrew Welker: Axiom's testing is very involved because there are a number of steps to testing the components: the crossovers, the drive units, and then the entire system. It is not simply a sweep to see if the speaker makes sound: we actually do very detailed measurements every step of the way.

The Crossover Network

One of the most important components of a loudspeaker is something called the crossover network (sometimes referred to as a filter network or a dividing network). It's basically a circuit board that contains electronic components such as resistors, capacitors and inductors. It's responsible for dividing the entire frequency band into the individual 'chunks' that the individual drivers will carry. For instance, you want to send the woofers in a loudspeaker only the low frequency sound. So the filter will actually prevent high-frequency sound from getting to the woofers. Similarly, for the tweeter, we don't want low-frequency sounds getting to the tweeter, just high-frequency sounds, so the filter will make sure only those high frequency sounds get to the tweeter. The crossover network design, along with the driver design, is also what allows us to manipulate the family of curves which is the most important design element of a great-sounding loudspeaker.

Because we manufacture pretty much all of our components in-house, including all of our crossover networks, we have the benefit of being able to keep very tight controls on the quality of these parts. Because they are such a critical component of the speaker, every single one of them is tested and measured.

Here we're sitting at what we've nicknamed the 'hotdog cart' where we have a measurement system which allows us to measure the electrical characteristics of each section of the crossover network individually: woofer, midrange and tweeter.

The Transducers

We go to the lengths of manufacturing our own drive units or woofers, tweeters and midranges at Axiom, even though it would be very easy to buy them off the shelf because there are lots of manufacturers making these types of drivers. One of the reasons - and really the most important reason to make them in-house, other than having full design control over the part - is that you then have full control over the quality of each part that goes into your loudspeaker.

There are a number of steps along the way while we are building transducers where we actually perform measurements on them. As a final test, just like the crossover networks, and just like the entire system is tested before it gets boxed up and shipped to a customer, each individual drive unit is boxed up and tested.

We made the investment a couple of years ago into a state-of-the-art measurement system from a company called ListenInc. It allows us with a very very quick signal sweep to perform an entire suite of measurements. In just three seconds, we are able to measure not only the frequency response or the amplitude response of the drive unit, but we're also measuring for impedance, for buzzes or distortion. All of those items are measured individually in our mini anechoic box that has a microphone mounted in it. Each one of the items will get a green light or a 'pass' if they are within specification.

We determine our own tolerances and they're very very tight. On something like an Axiom tweeter, a dB and a half is our measurement window, which is very hard to achieve if you're buying a batch of tweeters from another company rather than making them yourself.

This is really one of the most critical components - along with the crossover network - that make up the speaker. Cabinets are important, but it's also those components that go into a loudspeaker that are so important, and that's why we go to such great lengths to make sure they are tested and they meet our stringent quality requirements every step of the way.

The Mini-Chamber "Booth" Test

After we've gone through and individually tested the crossover network and all of the drive units individually, we assemble them into a speaker cabinet. Now we test the complete speaker as a system, to make sure everything has gone together properly and everything is wired properly, and that there are no issues with a loose wire, etc.

We actually have a small anechoic chamber on the production line. We stop the conveyor belt and mount the speaker pointing inwards into the chamber, where there is a microphone mounted. We'll do a frequency response curve using the same measurement and same system that we do in our large anechoic chamber. We'll also do a polarity test. The reason we do a polarity test is that there is a possibility (although it happens very infrequently) for the polarity of the input terminal to be reversed from what it should be. What would happen in that case is that you would get one speaker that was wired in-phase and one speaker that was wired out-of-phase, the sound would be all wrong and you wouldn't get any bass. So it's a very important aspect to check.

Finally we'll do a sweep at a high level where the calibrated measurement microphone is actually the operator's ears, because in that case we are trying to detect things that are very difficult to pick up with a microphone: things like wires buzzing inside the cabinet, a loose screw, etc.

So all of those aspects are tested essentially by ear after all of the other steps are done.

The Ultimate Test: The Anechoic Chamber

There is one speaker in our line up - the LFR1100 Omnidirectional speaker - which can't be measured at the same end-of-line test as our other products. There are a couple of reasons for this: one is that it's a fairly complex system involving multiple amplifier channels and a DSP box.

The other is because it's an omnidirectional loudspeaker, if we measured it in a non-totally anechoic environment, what goes on between the front and rear sections would mess up the signal. So we have to actually measure that speaker in the full size anechoic chamber.

When this Chamber Lab was built, we made sure to build it literally 20 steps from the production line. The reason we did that was so that when we encountered models like this that we had to test in this environment, it was near by.

The other reason is that it lets us do regular checks of quality by pulling product randomly off the line into the full-sized anechoic chamber, and then we can measure them against our references.

The measurements that take place on an LFR speaker are numerous. We measure the front and rear independently; we also measure them together. We do a full family of curves to measure the sound power.

The reason we do that on every model is because there are different interactions occurring, and those interactions between the front and back drivers can change those individual response curves, so we have to do a very detailed measurement here whereas the other models just need a single on-axis frequency response.

Hopefully that's answered the question of what we do for our production testing of our loudspeaker models. You can see that it's very involved, and the luxury of manufacturing almost all of the components in-house is that we can do this sort of testing along the way and guarantee a high-quality product that matches very closely to our references.

Andrew Welker: I thought it would be quite interesting today to show you a view of either a speaker you own, if it happens to be an Axiom Product, or actually what goes into building a speaker box. Obviously most of the time we only see what's going on on the outside of the speaker, not what's inside.

Let's start with the sleeve of the speaker, which is actually one piece that comprises the front, back, and the sides of the speaker cabinet. This is actually CNC machined out of a single, solid complete piece of MDF. This is a piece of our standard finish Boston Cherry vinyl. If I flip this up you can see that the vinyl is already laminated onto the MDF (or Medium Density Fiberboard), which is the wood that provides the strength and the good acoustic properties we want.

In this case the vinyl is actually providing the hinge to allow us to fold the front, back and sides together to make the cabinet. Then all we have to do is add the top and bottom pieces.

You can see we've got a number of different components here. We've got ports, already mounted. There's two on the back of an M80 and one on the front at the bottom.

The crossover network which divides the frequencies between the different drive units - the tweeters, midranges and woofers - is mounted here.

We've got braces, and in the M80 there are four window braces. Those braces are actually locked into these grooves called dados so that when the entire cabinet is glued together and the glue sets, it provides a very very rigid, very solid, vibration-free cabinet.

Another interesting thing that's inside any of our products that have a dedicated midrange are these black boxes: an independent sealed enclosure for each midrange. Because you don't want the midranges interacting with the air pressure from the woofers inside of the cabinet, they have to be isolated. To do that, we have these plastic injection-molded chambers that are air-sealed to the cabinet. There's a gasket that fits into a groove in the wood so that when the box actually meets up with this flat rib and it's screwed down, now we have an air-tight seal.

The box itself is quite interesting in its construction and is another example of the level of detail we go to at Axiom to get the best performance we can. More on that later.

Essentially, once the box is mounted, glue is put in all of the grooves and all of the openings in the back of the cabinet, it's folded around the top and bottom, and it's clamped together until the glue dries.

The Parts

The crossover network is responsible for dividing up the various frequency sections that are going to be reproduced by the tweeter, the midrange and the woofer sections. The reasons that this is critically important are:

1. It's the most important part of the integration between the drive units so that when you listen to the sound it sounds seamless: there's a seamless blend between each of the components
2. From a practical standpoint, if we tried to put bass signals into something like a tweeter, we'd burn it out instantly because it's not designed to produce those low frequency sounds.

Axiom's proprietary corrugated Vortex Port

Next are our Vortex Ports. Unlike many conventional ports that are simply circular in shape and are a complete cylinder on the inside, ours have these flared edges.

One of the things that happens is that when you play your speakers at high levels with lots of low frequency information, there is a lot of air moving through the ports. And the air can actually create turbulence at high velocities, which will cause noises. We call it chuffing. And it sounds like what you normally hear when wind is rushing through a door that's not closed properly.

By putting these little fluted areas into the port itself, both the inside edge and the outside flare, we reduce the air turbulence and hence get a much quieter port.

The other thing that happens is that we increase the effective surface area, or the cross-sectional area of that so that we have the ability to more tightly control the tuning frequencies.

Next, let's take a look at the backside of where the woofers mount in an M80. The brass-colored metal discs that you can see are T-nuts: metal-threaded inserts that mount from the backside with a little flange that keeps them secure against the inside edge of the front baffle. With a normal wood screw there is a risk: if you over-tighten it, it will spin and allow the screw to back off slightly, so you can actually get air leaks and other bad effects happening because now your woofer is not tightly tied to the cabinet. The T-nut allows us to put quite a bit more torque on the bolts that hold the driver in, which prevents that bolt from backing off in the future.

These T-nuts are on all of the drive units from the tweeters, the midranges and the woofers.

Injection Molding and Custom Design

Let's talk a little bit about this unassuming-looking piece of plastic which we call our midbox. Think of it as its own cabinet for the midrange drivers in products like our M60 Floorstanding Speaker and M80 Floorstanding Speaker. It's a fairly complex and involved piece of tooling that was required to make this.

Like any speaker cabinet, we don't want any sort of vibrations. We want a very solid, very rigid enclosure for the midrange. Being plastic, if this was simply a straight-sided, straight-walled part, it would be very flexible. We designed the ridges to create strength in the part. So what we are doing is reducing the effects of any sort of vibrations that can be created from the frequencies that the midrange is reproducing.

One of the other things that we're concerned about is the back wave of the midrange interfering with the signal that's coming from the cone of the midrange. We know that the sound comes off the front of the cone, of course, but sound also comes off the back of the cone. That sound - even with the damping material that's inside the box - will reflect off of the interior surface. That's why this surface has a convex shape to it. Between that and the ridges that are in the midbox, we can break up those reflections and smooth out the frequency response.

One of the things that we pride ourselves in is that we do all of our plastic injection molding and tooling in-house. The core and the cavity are two pieces: one creating the shape of the outside of the part and one creating the inside. All of the tooling was done in-house and we'll also mold this plastic part with our own molding machinery. We use something called ABS for molding parts in our 480-tonne press.

I hope you enjoyed this look at some of the design and engineering that goes into the inside of an Axiom loudspeaker.

Andrew Welker: I'm going to talk a little bit about the controls and the functions that are available on the backs of our subwoofers. These days, most of the actual set up and adjustments that you're going to be doing can be done within the menus of your home theater receiver or processor. But there are some cases, however, where you'll be using a conventional stereo amplifier to drive the subwoofers, so there are some adjustments that you need to set.

The first adjustment - and the most obvious - is the Volume Level. It's where you set how loud the subwoofer is going to sound for a given input signal. We recommend that if you're using a home theater receiver or processor, to set the volume as a starting point at the midway point. From there you can make the more fine adjustments using the set up menu in your receiver.

There's also the control on the back of the subwoofers that allows you to set the Crossover Frequency. In some cases it's just a two-position switch that allows you to set 80 or 150 Hertz; and in other cases it's going to have multiple settings from 40 Hz all the way up to 150 Hz. Again if you're using a home theater processor, you're going to set the crossover in the highest frequency setting which is 150 Hz and then you're actually going to set the crossover point inside the processor or receiver.

If you're using a stereo amplifier and you don't have bass management available to you, you're going to now set the crossover point to whatever makes sense with the speakers that you're using. Typically for a bookshelf speaker, an 80 Hz setting works well, and if you have the option and you're using larger tower speakers, something like the 40 or 60 Hz setting may work better. But it's something that you have to try and see which blends the best.

There's another setting called Phase which is in degrees. There's a 0° setting and a 180° setting. This is a setting that confuses people because if you just flip the switch with music playing, you're not going to hear much of a change at all immediately. This switch really defines how the subwoofer is going to interact with your main front speakers. To set it up is fairly simple: you want to play some music that has some good bass and mid-bass content in it, and then listen to the music playing with the switch in one position, and then switch it to the other position and listen again.

What you're listening for is there is going to be a setting that gives you fuller and slightly louder bass. That's usually the correct setting for your room.

Finally we have an input on our subwoofers that's labelled Trigger. There's an In and an Out available. The trigger simply allows you to turn the subwoofer amplifier on and off remotely from your home theater receiver or processor, so that when you turn the power on and off with your system remote control to the receiver, you'll actually be switching the amplifier in the subwoofer on and off.

This is a 12-volt trigger which is fairly standard in the industry. It simply uses an eighth-inch phono plug. So you're going to bring that signal from your receiver or processor and plug it in on the subwoofer amplifier. Now when you turn the electronics in the rest of your system on and off, it's going to switch the subwoofer amplifier on and off.

You'll know that's happening because normally the light on the back of the subwoofer will be green. If it's in the standby mode because you've turned off the power from the receiver it's going to turn red so that you know it's in the off position.

It's that time of year when our thoughts turn to hidden treasures, and a quick browse through an old Axiom article on DVD Easter Eggs lead me to wonder what was new in the world of secret scenes or other gems (commonly referred to as 'Easter Eggs' because you have to hunt for them ) on recently released Blu-rays. Here's a list of a few - do you have any to add to the collection?

The Hunger Games: On the special features disc, after the Lionsgate logo shows up and there is an animation of The Capitol, you can see various letters lighting up on the banners for each district. They reveal a clue to give you a secret message from Plutarch Heavensbee.

Try this at home: write down each of the letters. Then, press the down key on your menu pad as you're looking at a section of the Special Features Disc. Four of the sections will show you a list from Heavensbee. Use the flashing letters from above to decode the secret message.

Princess Bride: In the 25th Anniversary Edition of Princess Bride (or as we call it on the Axiom Message Boards, One of The Best Movies of All Time), there is an Easter Egg bonus clip that shows the 5 hours of makeup it took to convert Cary Elwes into Professor Rawscey from the Dread Pirate Roberts supplement.

Get to it from the fleur-de-lis symbol in the subtitles option of the set up menu.

The Amazing Spider-Man: Looking for a few laughs this weekend? How about Spidey and Green Goblin doing aerobics? Oh yah, eat your heart out Jane Fonda! This gag reel will give you a new perspective on our favourite crime fighting arachnid!

Web your way to this one by on the first disc of The Amazing Spider Man. Click on Commentaries. When you see James Franco / Harry Osborn, click on him to reveal the CGI Bloopers and Gag Reel.

The Avengers: Wouldn't it be great to know even more about the characters in this blockbuster? Well, now you can! If the Supplements didn't give you all the details you wanted, check out the Secret Files on main characters.

Be the hero in your household: when you're on the main menu, highlight 'play', and then click the left button on your remote, highlighting the SHIELD logo. Select it to reveal the secret files.

Monsters, Inc: This now-classic movie released a new blu-ray edition last year, and on it you can see the Monsters, Inc. employee handbook, as well as a guide to the 'in' jokes in case you missed them.

Hunter's tip: these Easter Eggs are on the Special Features disc; available by pushing the left arrow button your remove to open a door of menus.

Do you hunt for Easter Eggs on movies you watch again and again? If so, why not list your finds in the comments below?

*With thanks to Blu-Ray Easter Eggs and the Easter Egg Archive

My New Jersey home was flooded by Hurricane Sandy. As part of the opportunity to rebuild, and to feel good about moving back home, I decided I wanted to re-orient the TV room and wire it for sound and cat 6 networking.

Instead of the TV facing 15 feet to the back wall, it's been reposition over the fireplace and is visible from the entire 15 x 38' room which is really 3 rooms in one. As a musician, sound man and recording hobby guy, quality sound is important to me. I know a ton about live sound, very little about HT sound. I know speakers probably carry the most weight in the quality of a system. I'm a research guy and after lots of online reading I landed on the axiom brand, did lots more reading and went for it.

I like the fact that it's a direct to consumer product. It makes sense that some overhead is eliminated and that value passed to the end user. I wanted in wall speakers, and the design of the self contained boxes that are extended slightly from the wall and/or ceiling made logical sense to me with the DIY sound background that I have. Online, I found good reviews and bad review as there would be for most any product, I liked the fact that you have a forum for your supporters. I'm more of a forum lurker than a poster - but it's great for a guy like me to get a quick beat on what people like about the company and products and the like.

I moved my family back to our house on March 9th. It's still a construction zone with odds and ends to finish up. For example the fireplace mantel is not started yet (therefore I have not installed the VP100 center channel yet ). That said I did the audyssey for the speakers I do have set up and I can tell you that it's absolutely amazing! It's exactly what I had hoped to accomplish. Also, one of your sales guys actually called at one point during the order and I requested advice on placement of the rear surround speakers that I placed in ceiling (M2 in wall) and I followed the advice and could not be happier with the placement, (I also have the M3 as mains and also using your smallest sub). Very, very happy with the sound.

Andrew: Today we're going to look at how to wire up multiple subwoofers. We are big advocates of having more than one subwoofer in your system because it really smooths out the low frequency bass response in the room. Even two subwoofers can do a much better job giving you nice linear bass.

So the problem comes up as to: "How do I wire multiple subwoofers?"

Now, there are some home theater processors and receivers that have more Subwoofer Out on them. Usually it will only be two if it does have more than one. And in that case, it's very straightforward and pretty much self-explanatory: you're going to run a separate (usually) RCA cable from each of the Sub Outs on your receiver to the RCA inputs on your two subwoofers. If, however, like the vast majority of home theater receiver on the market, there is only one labeled Sub Out on the unit, you have a couple of options. One option is that you can use an RCA splitting cable, where you will plug one end into the Sub Out on your receiver, and now you have two Outputs that you can run individually to the two subwoofers.

The only problem with that is that typically the subwoofers are placed quite a distance away from the electronics, and you may have to run two fairly long cables to connect up the two subwoofers.

A better option in those cases is to do something called daisy-chaining, which allows you to bring the single Sub Out connection from your receiver to the Input of your first subwoofer, and now using the Low Level Output on the first subwoofer, you can now join to the Input of your second subwoofer amplifier.

So now we've chained these. The other benefit of this connection is that if you had more two subwoofers - three or four let's say - you can keep chaining them in this manner, going from the Input on one, to its Output, to the Input on the next subwoofer, out of its Output, to the Input on the following subwoofer, and so on.

So that's how easy it is to connect multiple subwoofers!

You May Also Like: If One Sub is Good, Are Two Better?

Continuing in our series of videos about subwoofer setup, Axiom Engineer Andrew Welker gives us an idea of what you need to know about subwoofer connections. It can be confusing - XLR, Line Level, RCA . . . what's the right one to use?

Andrew Welker: Today we're going to talk a little bit about connecting a subwoofer to a receiver. Connecting a subwoofer is not very difficult, particularly as most home theater receivers now have dedicated Subwoofer Outputs on them. The first thing that I want to mention is that before you make any connections it's a good idea to make sure that the power is off to the receiver and the subwoofer. You're not necessarily going to damage anything, but it can cause some startling bangs and noises if things are not right.

So if you locate on the back of your home theater receiver or processor, the output labeled Sub Out, most of the time you're going to find a common connection called an RCA connection. Here's what an RCA jack looks like and here's the plugin. On most receivers there's going to be one Sub Output; on some there will be two. You're simply going to plug your RCA into that Sub Out on your receiver or processor, and then the other end is going to connect to your subwoofer.

Depending on what vintage of our subwoofer you own, you may have a multi-plug which requires a quarter phone to RCA adapter which is included with the subwoofer. If you have one of those amplifiers, you simply plug the adapter in, and then you then you plug the other end of your RCA cable from your receiver's Sub Out into that input connection, and now that subwoofer is connected.

If you don't have one of these multi jacks on your subwoofer, you'll have one of these standard RCA jacks, and it's just a matter of plugging in to the RCA that is labelled Low-Level Input.

On some home theater processors you're going to find a different connection as an option, which is called an XLR connection. It's typically found on higher-end equipment and it gives you the benefit of being able to run longer runs of these cables with lower noise and interference. In the case that you've got an XLR Subwoofer Output on your processor, it's exactly the same as the RCA connection. If you have a multi-jack it plugs into the same connector that held the RCA adapter. If you have a version with a dedicated XLR input, it plugs into that input.

In case you're not using a home theater receiver or processor, and have a stereo system or two-channel system with an integrated amplifier or a dedicated pre-amp and amplifier, obviously you're not going to find a dedicated Subwoofer Output in almost all cases with those electronics. So the question then is how can you hook up your subwoofers? In the case where you've got an amplifier that you need to hook up to the subwoofer, you're going to use what's called the High Level Connections, and these are identical to the Speaker Connections that you would use on a typical amplifier.

Now, you have a couple of options here: you can either run your amplifier connections to the main speakers and then run another set of speaker cables to the subwoofer.

Alternatively, you can either wire from the amplifier to the subwoofer and then jump off to your main speakers or vice versa: you can go to the speakers from the amplifier and then from the main left and right speakers you can jumper to the subwoofer. In any case, what you're doing is you're simply going to connect both the left and right Speaker Outputs, wherever they are coming from, to the input of the subwoofer amp. Now you have available the same signal that you would coming from the Sub Out on a processor.

Now that you've got your subwoofer connected up in the manner that works in the manner that works with the electronics that you own, now's the time that you can power up your electronics, plug in your subwoofer, power it on, and then begin to make the subwoofer adjustments and set up.

There's something so exciting about unboxing a new home theater system. You can almost smell the popcorn in the air . . . but once you've got everything in your room and you have the front speakers, center channel, and surround speakers in their designated space, you're left with the one speaker whose placement isn't immediately obvious.

Andrew Welker, Axiom design engineer, has a beginning guide to subwoofer setup in the video below.

Andrew: Today we're going to do a preliminary introduction to where to place your subwoofer in the room. Now, subwoofers, and the way they behave and interact with a typical listening room, is a very complex subject. There are all kinds of tools and other things that will allow you to get very very precise ideas of where you can place the subwoofer for the best response. But a lot of those techniques don't work well if you don't have a reasonably good starting point.

Initial Placement

Conventional wisdom says you want to take your subwoofer and drop it in the corner of the room. In many cases, that will give you the loudsest bass, but in most cases it won't give you the smoothest and most linear bass. So it's a decent starting point, but don't assume once you've put the subwoofer down and in place that it should stay there necessarily.

If you're forced into a certain location - and in many homes the only place you can put your subwoofer is close to the television set, which usually means it will be behind either the right or left front speaker - and probably in the corner, unless you've got an L-shaped layout. The corner placement is going to give you the biggest amount of what's called room gain, which is additional output because of the loading of the room boundaries (the walls and the floor). If you are limited in terms of your placement, even if you only have a couple of feet to the left or right to play with in any direction, you should try moving the subwoofer out from being up against the corner, moving it to the left or right by a few feet as much as you can.

As you do this, listen to music you are familiar with, and try to find the position that gives you the smoothest bass. Even a couple of feet of pulling the subwoofer out from the corner can smooth out the bottom end significantly.

Two Subwoofers

Now, if you have two subwoofers in your setup and again you're fairly limited in your placement, you're going to do exactly the same thing. I always like, when I have two subwoofers, to actually set them up in terms of looking for the best placement separately, and then balance the levels and make the adjustments with both of them playing, after you've found a good position that gives you the smoothest bass for each subwoofer individually.

If you're not too concerned with having the subwoofers behind the left or right main speakers in the system, a really good technique is to do something called the subwoofer crawl. Now this may sound a little bit strange, but it really works.

The Subwoofer Crawl

The subwoofer crawl is simply a matter of taking your listening seat and either moving it, or, if you have a large couch then just placing your subwoofer as close as you can to where you're going to be sitting listening to the system. Then connect it up as usual and play some movies or music that have some good low frequency content in them.

Now what you're going to do (it sounds silly but it works) is get down on your knees and crawl around the perimeter, the outside edges of your room, listening for when the bass smooths out.

Subwoofers interact with the room in a way that causes what are called room nodes, which are peaks and valleys in the response, and these occur at different frequencies depending on the room and where the subwoofer is placed. Now these peaks and valleys mean that as you crawl around, you may find some spots where all of a sudden you have very very loud bass, but it doesn't sound very smooth.

The flip side of that is that you may get into a position where you hear almost no bass at all, or very little - it doesn't sound very full in that position. In that position you're going to be in a room null, where the output is actually cancelling with the size and dimensions of the room.

By doing the subwoofer crawl, you can easily listen for the spot that gives you the smoothest low frequency bass. That's a good position to try by now putting the subwoofer in that position where you heard that response, and going back to your listening position. Sit down, and see whether or not that placement actually works.

It's a good easy technique that doesn't require you to be technical, doesn't require measurement equipment, and really works in most rooms.

Related Video: How to Do the Subwoofer Crawl with Alan Lofft

Related Article: Do I Need Two Subwoofers?

Related Article: The ABCs of Bass

Aim for Optimal Positioning First

As you can see from the picture to the right, Dolby Labs recommends placing surround speakers to the left and right of the sitting area, above ear level about 2 feet or more, and somewhere between 90 and 110° from the center.

So what do you do if there are no walls in that area, or if that height isn't going to work for you? Don't worry: Axiom's unique driver arrangement means that you're going to get great surround effects even if things aren't ideally placed.

If it suits your room better, consider using stands for placement. The QSS Surround Stand, for example, is 38 inches high, placing the speakers above ear level when you are sitting on your couch.

Some rooms have different challenges: for example, your home theater might be half of an open-concept finished basement, as a lot of our customers' are. In that case, you may want to mount the speakers from the ceiling so that they are still in the main listening area, rather than on a wall far away from the center of the action.

The only place you can't place Axiom surround speakers? In a shelving unit or bookcase. Because there is a driver on the bottom of the speaker, it can't sit on a shelf the way a traditional bookshelf speaker does. We've had innovative customers come up with mini-stands to elevate the quadpolar speaker in a bookcase; if you'd like to try that route just be sure to get between 1.5 and 2 inches of clearance between the speaker and the surface beneath it.

For more detailed placement options, including 7.1-channel surround-sound options, read our article on "Home Theater Layout".

Choose the Best Mounting Option

As you can see in the video to the right, there are a lot of mounting options with Axiom's speakers. The easiest (and most innovative!) if you are wall-mounting is to use the included Power Mount bracket. Unique to Axiom, we engineered this bracket to get around the problem of banana plugs forcing the speaker to jut out from the wall.

To use the Power Mount bracket, simply carefully remove it from the speaker, attach it the wires coming from your receiver, and then mount it to the wall. The QS8, QS4, or on-wall speaker model simply slides into the two gold-colored hooks on the back of the speaker and makes the electrical connection.

The QSS Surround Speaker Stand also includes accommodation for using the Power Mount on it.

The next option is the hex-bolt at the back of the speaker. This will accept our Full Metal Bracket or our Full Metal Ceiling Bracket, or a variety of other after-market speaker mounts. If you choose to install surround speakers in a position where you need to angle them or hang them from the ceiling, these are the best options.

Using either of the brackets is easy. Simply use the supplied Allen key to attach the speaker mount to the speaker. Next, using a stud locator (or the knock test if you prefer), screw the body of the bracket into the stud or ceiling joist. Use the provided 1 3/4" screws to ensure a secure connection. Once that is in place, reattach the pivot portion of the speaker bracket using the hex bolt and nut.

The brackets also come with a small wedge. This wedge is for making precise vertical angle adjustments once the speaker has been installed.

Making the Connection

There are a couple of options when you choose the cables for your speakers. If you are installing surround speakers on outside walls, you may have a challenge fishing the wire through the tightly-packed insulation. In that case, Flat Speaker Wire can come to your rescue. The wire is flat and spreads the wires along the surface of the wall instead of in a tube, so you can lay it flat and then paint or plaster over it. You can also run it under carpets and baseboards, since it is just 0.024-inch / .60 mm thick. Just be sure not to drive a nail through it, breaking the connection!

If you're running wire inside walls to a central location, you need to look for speaker wire that is in-wall rated. This rating means that it is properly insulated against fire risks, and it can safely be run from the back of your surround speakers through the wall to the floor or ceiling and out to the amplifier. Insurance companies prefer you use this sort of wire.

And finally, if you're using stands or you're not concerned about wires showing, the least expensive and most commonly-found wire option is regular bulk speaker wire. If you're choosing your wire from a large selection in a store, just ensure that you are getting 99.9999% oxygen-free copper wire.

• if your speaker wire run is less than 25 feet, a 14-gauge wire is fine
• for runs less than 15 feet, you can use 16-gauge or lower
• if you're running wire 25 feet or further, you need to use 12-gauge cable for the least resistance on the line.

(For an explanation of why that matters, and why you don't need to spend more on cables than you do groceries, read our article entitled "What's in A Cable?" If you still want to buy expensive cables after reading it, you'll know you're doing it because you want to and not because some salesman told you you have to, and that's all we ask!)

There you have it: a comprehensive look at what you need to think about when you install surround speakers. Have you got any innovative installation ideas or helpful suggestions? Post them in the comments below!

Andrew: Basically today I wanted to go over a couple of points about our ADA amplifier series that differentiates us with some of the Class D (sometimes called Switching Amplifiers) that are on the market. There's a lot of them and they all tout the same sort of high efficiency, cool running, high-power-for-small-size features. We have all of those things, because this is a Class D-based amplifier.

In fact, this module in my hands is from the ADA 1500 amplifier, our largest model, and this is essentially a complete (minus the power supply) 2 times 650-watt into 4 ohm amplifier. It's something that was unheard of not that many years ago - to get that sort of power out of something so small.

But as I said, there are a lot of companies doing Class D now. However, there are a couple of things we're doing that we do a little bit differently from most of the products in the market. One is that we use a conventional - sometimes called 'linear' - power supply, with a large toroidal transformer and massive amounts of power supply filter capacitance. Basically we've gone that route because we find that a linear power supply works a lot better when you have to divide power amongst a number of different amplifier channels, as you find in multi-channel amplifiers. And we've also discovered that they're quite a bit more reliable than a switching type power supply.

One other thing that separates our amplifiers from most of the amps on the market is that our series is completely modular and factory-upgradable. The bottom of the amplifier chassis is what we call a power supply motherboard that delivers all the power supply voltages to the different amplifier modules. The modules themselves can simply plug in to positions on the motherboard to allow us to configure the amplifier in anything from two up to eight channels.

This means that a customer who buys the amplifier in a two-channel or three-channel configuration can easily upgrade at any time by simply sending the amplifier back to the factory, as their power requirements and their system evolves over time.

Amie Asks: What is meant by Power Supply Filter Capacitance?

Andrew Answers: Power Supply Filter Capacitance helps in the conversion from Alternating Current from the wall to turn it into direct current to supply the amplifiers. Having a large bank of them functions somewhat like a battery - they store energy. So the larger the bank is, the larger the size of the capacitors, the more energy storage there is. So what that means is when you have short term peaks where you need a lot of power, the power supply is able to deliver it without dropping in level at all. So they're a large energy storage bank.

Ian Adds: The large capacitance adds something known as dynamic headroom, and since large power in music and movies is normally demanded for very short bursts of time, allowing the amplifier to deliver these bursts of power without clipping.

Andrew: Part two, in continuation of part one. A couple of important details. One, many in-wall speakers that you'll see on the marketplace actually are sunk into the wall so that the drive units sit below where the drywall surface or the wallboard surface would be. That's actually a very bad thing acoustically, because the wall edges that stick out past the drivers cause reflections and what's called diffractions around the drive unit. So instead of getting a nice even spread and a spacious sound, you can get a very localized and closed-in sound, which sounds very unnatural.

The other thing that sounds distinctive in our in-wall products is that many baffle materials that you'll find on the market are actually plastic. We use MDF, which is the same material that we use in our bookshelf and floorstanding loudspeakers. The reason we want to use something like MDF is that the baffle, which is the part of the speaker that the drive unites (the woofer and tweeter) are mounted to, are subject to the most vibration. You want a material that can dissipate that vibration. MDF is excellent at that.

So there are a couple of more reasons that the Axiom in-wall products result in excellent high-quality sound.

¹Amie Asks: Hey Andrew, what exactly is diffraction?

Andrew Replies: Hmm, how to describe it to you. . . Diffraction: if you ever drop a pebble in a still pond you'll see the ripples go out in a circular pattern. If that ripple pattern comes into contact with something - a dock or a duck or whatnot - in some cases the ripple pattern will actually bend around it, and in others it will start more ripples moving in different directions.

The same thing happens with soundwaves. Whenever they encounter any sort of an edge, then they tend to reflect in different directions, at random. It's somewhat dependent on what the frequency of the waves, but it's a random set of reflections that happen when soundwaves encounter an edge or a boundary.

Now in the case of in-wall speakers and the inset variety on the market, there are two things that happen - you get unknown addition and cancellation in the sound that's coming from the speakers, which makes the speakers less linear; but you also get a reduction in the amount of dispersion or spread of the sound, making it easier to pinpoint the location of the speaker. This is obviously not something you're looking for in a speaker.

See Designing an In-Wall Speaker: Part 1

Alan Lofft explains how to do the subwoofer crawl.

We've all been there - maybe it's your house, maybe it's a neighbour's - where this time of year there is an ornament on every surface and no window is left unadorned. You know, the type of decorating that makes the mall look under-done . . . And that's all well and good in some rooms, but in your man-cave? It's asking too much!

Send in a photo of the most worst affront that has happened to your speakers when your family was decorating for the holidays! Stockings muffling your tweeters? Snowmen wiping out woofers? Post'em here - you'll win our sympathy, and if the situation is the worst we've ever seen, you'll win a $50 prize, too! Details.

[Contest is Closed]  

Contest Details:  Submit a minimum of 1 picture with your name and email address.  If your picture is chosen as the winner, we'll send you a gift certificate for $50 at AxiomAudio.  Winner will be chosen December 30th, 2012.  Prize is not redeemable for cash; only for loudspeakers or accessories at www.axiomaudio.com.  We may choose to use any or all of the photos at our discretion.  Please do not enter if this contest violates any federal, provincial, state or laws.  Questions?  Email us!

I caught up with Andrew Welker in our anechoic chamber (this time we put the floor in so I could turn the camera around!) and asked him about his strategy.

Andrew: The biggest challenge with an in-wall speaker is the fact that you are mounting it in a wall, which is not an ideal place for a speaker. The challenge involved in designing an in-wall speaker for that application is firstly most homes in North America are built with standard 2x4 studded walls, so you've got a very shallow opening that you have available to mount the speakers in.

The problem with that is that, all else being equal, the more cabinet volume you have available or the more space you have inside the speaker, the more bass that you can get out of it, particularly at the lower frequencies. So you're limited in the amount of space that you can actually use up because of that standard 2x4 studding.

As an example here, we've got two speakers that are essentially identical models. One is the T2 In-Wall Speaker, the other is our M2 Bookshelf Speaker, and if I turn them sideways you can see the T2 in-wall is a tiny tiny little cabinet. It's probably got less than 1/3 of the internal cabinet volume of the M2. So that would lead you to believe that an in-wall speaker such as this would have no bass.

The benefit of having the wall is that the wall boundary itself that's going to surround all the sides of the speaker helps to increase the amount of bass you get from the speaker. It's called the boundary loading effect. As long as we design the in-wall speaker in that boundary, we can now get a smooth balance and we can get good low-frequency response.

We're standing inside our anechoic chamber, and in here we actually use a false all which we mount the in-wall speaker into so that we can get an idea of what the typical boundary loading is going to be. Now, you're still not going to get as much bass out of an in-wall as you would out of the equivalent bookshelf model. But when you blend that system with a subwoofer, it's going to give you performance that is pretty much identical to what you would get with a pair of a bookshelf speakers with that subwoofer.

So that's really the biggest challenge: that we don't have a lot of mounting space available when designing an in-wall product.

1896 - Piano Rolls

A piano roll is a continuous roll of paper with holes punched into it.  The perforations represent note control data.  The roll moves over a reading system known as a 'tracker bar' and the playing cycle for each musical note is triggered when a perforation crosses the bar and is read.

1950 - Gramophone Record

An analog sound storage medium consisting of a flat disc with an inscribed, modulated spiral groove.  The groove usually starts near the periphery and ends near the center of the disc.  Phonograph records are generally described by their diameter in inches (12-inch, 10-inc, 7-inch, etc).

1964 - Cassette Tape

The mass production of compact audio cassettes began in 1964 in Hanover, Germany.  Prerecorded music cassettes (also known as Musicassettes; M.C. for short) were launched in Europe in late 1965.  The Mercury Record Company, a U.S. affiliate of Phillips, introduced M.C. to the U.S in July 1966.

1988 - Compact Discs

On March 2nd, 1983, CD players and discs were released in the U.S. and other markets.  This event is often seen as the "Big Bang" of the digital audio revolution.  The new audio disc was enthusiastically received, especially in the early-adpoting classical music and audiophile communities.

2001 - MP3 and iPod

The MP3 file format was approved by an audio consortium as a file format in 1993.  The iPod MP3 player was announced by Apple on October 23rd, 2001, and released on November 10th, 2001.

Present - The Cloud

The shift has gone from tangible mediums such as teh compact disc, towards getting full accesss to an entire library of music - litterally millions of sounds, that aren't bound by just 'Gigabytes' of space.  Pandora, iTunes, Spotify, Rdio and even Grooveshark are taking our music consumption to the cloud! What's your preferred medium?  Vinyl addict or Cloud-or-bust?

Step 1: Get The Seating Plan Together Consider how you're using your room. Is the 'sweet spot' - the main seats in the home theater - opposite the TV or off to the side? Where is the rest of the audience in the room? Ideally you want as many people as possible to fall into a triangle formed between the front, left, and center speakers, and the listening area.

Step 2: Consider The Source

Most dialog is hard-mixed by the studio to come from the center channel. If you're like most of us and you had a stereo system before you had a home theater, you're forgiven for spending more time thinking about front left-and-right speaker placement than center channel placement: however, this speaker really is the keystone in home theater speaker systems. Burying it away as an afterthought just won't give you the wow you're looking for.

First, make sure the center is as close as possible to the screen. Having the center channel coming from the ceiling or close to the floor can cause voices to sound disembodied - and with good reason. If you have to put a center channel on the floor, try to get one like the Axiom centers that have an angled cabinet, so you can point the speaker's drivers up at the listener.

Next, consider where the speaker is in relation to what it's sitting on. If you have it hanging freely on a wall, you probably have excellent sound dispersion. If, however, you have it recessed into a cabinet, try pulling the center forward - half an inch if you can manage it - so that the front face of the speaker sits ahead of any boundaries. This opens up the sound and can make the most noticeable difference in the intelligibility of movies and 5.1-channel television show broadcasts.

If you do have the speaker in a cabinet, see if it's possible to remove the rear panel of the cabinet to give it more air to breathe. The center uses the highest acoustical energy of all the speaker channels and you want to feed it as much air as you can to take advantage of that energy.

Step 3: Position The Main Channels

Now that you have dialog firing right at you and you can understand every word the actors are saying, it's time to start adding in the left and right channels. You want these speakers to be about 25° off the center channel to each side, pointed in at that sweet spot. Ideally, the tweeters on the left and right speakers will be at your ear level when you're seated. Also ideally, the speakers should be the exact same distance away from the center channel, and from you. These speakers carry most of the movie's soundtrack, so getting this placement right will make movies more realistic and engrossing.

This is a great place to experiment: put on some tunes you love and sit in the prime seat. Ask your kids / your friend / the babysitter to 'toe' the speakers in slightly. (Toeing a speaker in means that you nudge a speaker from facing straight on to having a slight angle towards the center. The back pushes out, away from the video display, and the front of the speaker rotates in slightly.) Do this in small increments, and ask your helper to step out of the active sound window after each adjustment. You're listening for more detail and fullness from the speaker. And like love, you just know when it's right. Too far and the sound muddies and you hear each speaker distinctly (like you do as you walk past speakers in retail stores or restaurants). Not far enough and the speakers just sound 'good', not 'I'm-never-leaving-my-couch-again' awesome. Your goal is to create a convincing soundstage where music is all around you and the speakers create seamless, continuous sound.

Remember that sound waves can be interrupted by furnishings. If you're not getting that perfect sound, examine the room: do you have a large upholstered chair blocking your view of the speaker? Chances are it's blocking some of the sound waves too. Try moving the furniture out of the path of the speaker and listen to the changes it makes.

Step Four: The Effects Channels

Once you have those three speakers singing from the same song sheet, it's time to position your surrounds. Some people call these speakers Rear Channels, but Dolby Labs calls them Surround Speakers and suggests that you position them to the left and right of the seating position. If you can't place them exactly to the side, move them slightly behind the listening area rather than ahead of you. Dolby recommends a distance of 90 - 110° to your seat. The speakers should be higher than your ears, if possible, so try to wall-mount them or get special speaker stands that will elevate them above your ears when you're seated in the sweet spot.

Having surround speakers properly positioned opens up your home theater, creating the space and depth required to make the illusion of being in the center of the action real. Placing them higher on the walls can allow for the best reflections, increasing the sense of envelopment.

7.1 Channel: If you have two sets of surrounds, position the second set behind the listening area, again high on the wall, at about 150° relative to the center speaker. 7.1-channel surround sound is especially powerful in large rooms with high ceilings, keeping the action all around you without gaps in the sound.

Step Five: Position The Subwoofer

Now for the deep bass: your subwoofer provides the sound below 80Hz. The good news is bass is omnidirectional: that means you can put the subwoofer in any of several places in your room, depending on your furniture and how you use the room. If possible, start with the subwoofer in the front of the home theater and listen for clearly defined drums, deep organ and and footfalls or explosions. You'll find that the closer you put the subwoofer to the corner, the more energy you will get. Oddly, this may be beneficial in some room environments. You will need to experiment with sub location to find the best for your room.

Step Six: Receiver Settings

Now that your speakers are in their proper positions, you can sit back, relax, and . . . tweak. If you have a tablet, download an SPL meter to do this part of the set up. If you've been into audio for a while, you may already have a hand-held SPL meter that will do the job. Some receivers actually come with a calibration microphone you can use for set up as well.

Enter your receiver's OSD (on-screen display) and let the receiver play pink noise through every channel. You'll clearly hear which speakers are too loud, and which ones aren't loud enough. One of the most important things to check here is the volume of the center channel. You don't want to turn the whole soundtrack up to hear dialog more clearly, so spend time adjusting the center channel to get enough output so that you can clearly hear what is happening.

While you're in here, experiment with the crossover settings. The optimal crossover setting is likely going to be 80Hz. Again some experimentation may result in finding a better crossover point for your room. If you have large front and/or centre channel speakers you can try moving the crossover point down for those channels.

When you are finished with these settings, pink noise or test tones run through every channel should produce a smooth, even sound.

A Few General Tips

If you're into precision and you're measuring distances for speaker placement, remember to measure from your ears, not your couch cushions.

Exciting bass is one of the most important features in a home theater. If your subwoofer isn't giving you the incredible experience you're seeking, spend some time going through our Subwoofer Placement Tips, or consider adding a second subwoofer for smoother bass distribution.

If dialog isn't crisp, you may need to spend extra time fine-tuning center channel sound.

Large room? Large speakers? Consider adding extra amplification to get more dynamic headroom. More power means more detail and more clarity - the goal of any home theater aficionado!

That's it! Your comprehensive plan to preparing your new home theater speaker system for debut! Have you got any tips I missed? Share them here!

Andrew: Omnidrectional speakers are probably one of the more challenging types of designs that a loudspeaker designer can undertake. Part of the reason is that you have to deal with a lot of factors in terms of how the speaker interacts with the room, and how the different parts of the speaker interact with one another.

One good question that I often get is "Why omnidirectional in the first place? What's wrong with a conventional forward-radiating speaker?" And the answer is nothing. Axiom builds a lot of very successful models, including the award-winning M80, that are forward-radiating speakers. [Forward radiating speakers] perform extremely well, they image extremely well, and they can be totally neutral if properly designed.

What omnidirectional does is it just opens up the sense of space and proportions of instruments and singers and things that are going on in the musical stage. It also - for me, one of the most important aspects, and one of the most enjoyable - is the fact that omnidirectional speakers seem to have a sound that emanates from nowhere and everywhere at the same time. So the speakers essentially disappear. When that's done properly it really allows you to think for a second that you're now taking part in a live musical experience, rather than listening to a reproduction, and that's extremely compelling.

Sound radiates from the front and back of the LFR1100s

The issue with omnidirectional speakers as I mentioned is that they're tricky in terms of the interactions. One of the basic interactions which we can measure in a space like inside an anechoic chamber that we're in right now, is how the front and the rear drive units interact with one another. There's some issues with cancellation between those drive units and interaction between them, without even bringing the room and reflections into the equation. The only way that we've been able to overcome that is through the use of a circuit that incorporates a DSP or Digital Signal Processor. This allows us to tailor everything that's going on with the front drive units and the rear drive units independent of one another. That allows us to overcome any issues of negative interaction between the parts. This allows you to get a much more neutral tonal balance than a lot of omnidirectional and bipolar-type speakers that are on the market.

The other question I get very often is "What happens when you put this sort of speaker in different rooms? What happens if I place it fairly close to the room boundaries or the back wall."  Admittedly things will change depending on where the speaker is positioned, but that holds true for any loudspeaker. If you've ever moved your speakers around and played with positioning, you know that it impacts the sound. This sort of loudspeaker is no different.

One of the things we've been able to address is the rear wall positioning. Again, that's through the use of the DSP. If your speaker has to be placed fairly close to the back wall, we're able to compensate so that you still get the spacious full effect of the LFR speaker even though it's not maybe ideally positioned out in the room a couple of feet from the rear wall.

So those are a couple of areas that we've managed to address that really propel the performance of the LFR beyond any of our other products.

Read more about Axiom's Research and Andrew Welker.

"I remember that speaker!" Ian exclaimed. "I heard it - at Brent's store! Didn't sound too bad actually!"

A quick note to Brent had him reveling in nostalgia, and digging old literature out. "Those are relics from the past. They were available in their transpulse series or you could buy the plasma amplifier and add to your existing speaker. Gave off a very obnoxious smell especially when driven hard but incredible when you needed a light in the wee hours."

He went on to explain that they were used in conjunction with a tweeter in order to have enough output for everyday listening.

Here's what he dug up on Wikipedia:

Plasma or Ion tweeter Because ionized gas is electrically charged and so can be manipulated by a variable electrical field, it is possible to use a small sphere of plasma as a tweeter. Such tweeters are called a "plasma" tweeter or "ion" tweeter. They are more complex than other tweeters (plasma generation is not required in other types), but offer the advantage that the moving mass is optimally low, and so very responsive to the signal input. These types of tweeters are not capable of high output, nor of other than very high frequency reproduction, and so are usually used at the throat of a horn structure to manage usable output levels. One disadvantage is that the plasma arc typically produces ozone, a poison gas, in small quantities as a by-product. Because of this, German-made Magnat "magnasphere" speakers were banned from import to the USA in the 1980s.
Source: http://en.wikipedia.org/wiki/Tweeter#Plasma_or_Ion_tweeter

Brent went on to explain that Magnat was a German design that had its heyday in the 60s and 70s and then faded off from there. A friend of his had the speakers in a room roughly 20 x 10 and if you listened to the speakers for 90 minutes or more, you'd have a headache from the fumes.

Did you ever hear these (or other) Plasma tweeter speakers? What's wild and wonderful speaker designs do you remember? (Or, in the case of Axiom's friend MadBeggar, what wild and wonderful speaker designs are you cooking up in your basement right now?)

First Place: Graeme: At first listen, I was hooked.

SecondFirst Place: Gary (slightly late but too good to miss): Axiom, don’t stay home without ‘em.

Second Place: Luc: Turn them on, they will disappear!

Graeme and Gary each get a $50 gift certificate, Luc gets a $25 gift certificate, and if you were one of the ones in the top 10 we really loved but didn't quite make the top three, you will receive a special something in your inbox today too. Thanks so much to all who entered!

This was a really fun contest!

Brent and I enjoy some of the same books, and one that both of us got a real kick out of was "Not Quite What I Was Planning", a collection of six-word memoirs that encapsulate peoples lives - some of them funny, some of them bittersweet, some of them profound.  For example, a few contributions:

"Dad died, mom crazy, me too." — Moby

"Couldn't cope so I wrote songs"— Aimee Mann

"Macular degeneration. Didn't see that coming." — Ian Gould

"Brought it to a boil, often." — Mario Batali

. . . you get the drift.  So Brent and I were musing about what our audio six-word memoir would be.  What six words characterize your experience with music?  Can you do it in just six words?  It's surprisingly challenging!  Message board member Seabear's sig file, for example, wouldn't qualify:

"Axioms; For when you've just Gotta have More Cowbell!"

but

"It's Axiomatic: I need more cowbell" would definitely qualify!

Brent took the first try at it - his six words . . .

"No words to describe my sound!"

What are your six words? Post them here! The best phrase will win a $50 Axiom Gift Certificate. $25 for the first runner up!

PS - Mine after marrying a loudspeaker man? Well, bonus points if you noticed the length of the title of this post . . .

All quotes are excerpted from http://www.smithmag.net/sixwords/

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Take a look at what's going on in the Twittersphere to get a glimpse of what people are saying right now about their problems regarding scuffgate.

Do you think it's an overreaction from consumers or was Apple shortsighted in the durability of their latest and greatest product?

A recent Wall'o'Fame submission of a customer's beautiful 2.1 channel system got me thinking: how do you know if you're better off with sat/sub combination or two floorstanding speakers?

Turns out the answer is pretty simple: it's a matter of taste!  A bookshelf-speaker-and-subwoofer combination can do an excellent job of reproducing both highs and lows.  It's a significant step up from the speakers built into your television, and it does a great job of providing high-quality sound in a small room, den, dorm, or an apartment where running wires for surround sound isn't feasible.

It's also a great step into 5.1 channel home theater if you're building your system as budget allows.

Two floorstanding speakers are another way to approach a new audio set up in your home.  By sheer volume of the cabinet, they produce more bass than a bookshelf speaker, and in some rooms you'll get enough bass without feeling the need to add a sub.

Floorstanding speakers are often a three-way design, and the crossover is designed to separate the high, midrange, and bass frequencies.  It's defacto a fuller sound than a bookshelf speaker and a subwoofer, but with careful crossover adjustments you can do a good job of getting all the frequencies from bookshelf speakers.  For more information on setting up stereo speakers, read Alan Lofft's article entitled "Stereo Set Up Guide:  What The Pros Know."

Some floorstanding speakers, like Axiom's, have ports in the front or back.  These speakers are referred to as bass reflex speakers, and they use the port to move more air through the cabinet.  If you're fresh out of physics class, you'll recall that the more air you move through a speaker, the louder it can play.

Floorstanding speakers are definitely the right choice for larger rooms, and if you know you won't be adding a sub at any point they're a great choice for getting a full range of sound in just two boxes.

What do you prefer - a bookshelf-subwoofer 2.1 channel system, or a great pair of floorstanding loudspeakers?  Let us know!

Looking for a way to get high-end sound in any room of your house?  In wall ceiling speakers may be the answer!

Whole-house music is something a lot of us yearn for - it can be as practical as wanting to listen to the radio while making lunches in the kitchen, or as decadent as wanting the music to follow you no matter where you are during a party. Regardless, few of us have the space (or the inclination) to put full-blown bookshelf or floor standing speakers in every room of the house.

But, let's be candid . . . the sound that comes out of the tin cans in the ceiling at your dentist's office is not exactly the effect you were hoping for in your quest for audio nirvana.  So how can you ensure that the sound in your kitchen is as good as the sound in your den?

1. Opt for ceiling speakers that have fully enclosed backs.  If the speakers you are choosing are open at the back, the sound has not been fully engineered.  The cavity in the ceiling - the amount of insulation - the amount of room before the next wall or other obstruction - will all effect the sound. If you choose a speaker with a fully enclosed back, on the other hand, you know that the designer has finely-tuned the  speaker to sound its best no matter where it is installed.  The bass and treble output has a known quality, regardless of whether the speaker is being sunk into acoustic tile or an all-wood ceiling.
2. Think about placement.  The same rules of separation apply when you are installing in-ceiling speakers as when you are installing traditional stand-alone speakers.  Picture a triangle.  If you are standing mainly at the sink when listening to in wall ceiling speakers - doing dinner prep or whatever - ensure that the distance between the speakers is at least half of the distance to the listening position.  If you are standing 12 feet from where your speakers are, that means the distance between the left and right speaker should be a maximum of 12 feet and a minimum of 6 feet.
3. Watch out for reflections.  In wall ceiling speakers are often a nearly-invisible option for living rooms where stereo listening is key.  If you place the speakers too close to a fireplace or large window, you may hear reflections from the hard surface muddying up the sound.  Also make sure your speakers aren't too close to corners of the room - those corners will exaggerate bass response.

Oh, and by the way, we know that most people think 'round' when they think in wall ceiling speakers . . . but as our customer's beautiful installation, pictured above, shows, it's hip to be square, too!

Our customers have lots of experience building a home theater!

If so, get the inside track on what to do when building a home theater room by taking advantage of this hard-won advice from our message board members:

1. Buy more cable than you had anticipated. Accounting for twists, turns, reroutes, and doubling-back means that what once looked like more than you could ever need is now labyrinth-like maze that that needs to be fed ever-increasing lengths.

2. Remember that there are other rooms in the house where you may not want to be able to hear the movie or music. Adding extra bends in your HVAC pipes will help diffuse the sound. Conversely, adjacent rooms with no doors in between will suck up lots of sound - plan your speakers and subwoofers accordingly.

3. Future-proof your system by starting with a receiver with enough channels of amplification for you to grow into. Sure, you may be starting your home audio system with a pair of stereo speakers and a sub, but eventually you'll want to expand to 5.1-channel surround sound, and then 7.1. Make sure your receiver has pre-outs so you can expand your output power to really show off the capabilities of your floor standing speakers or home theater system.

4. Ditto for your television. You may not think you want internet connectivity / hdmi capabilities / a USB port, but with the speed our devices adapt and integrate, future-proofing here makes sense too.

5. If you are lucky enough to be doing a from-the-studs build-out, wire for a couple of options. You may think you know the best location for your subwoofer now, but once all the furniture is in place you may find the room nodes dictate a different position. Decorator-conscious spouses may want to turn the room's seating around, and subsequently all your equipment (don't ask Ian how I know about this one!) Being pre-wired for this possibility will make everyone's life easier.

6. Again, if you're lucky enough to be wiring before drywalling or sheetrocking, take photos of the wires before you cover them up so they're easy to get to if you need to make a last-minute change. Bonus points: run pull-ropes so fishing wires after the wall is covered up isn't as difficult.

7. Try to keep audio and video cables separate from A/C cables. The added interference could introduce humming and buzzing that will drive you crazy.

8. Plan for your kids' friends to suddenly find your house their new hangout. Put thick padding under your carpet and invest in big throw pillows for the crowd that will materialize on your floor during sporting events, awards nights, and new release parties.

9. Think about different lighting scenarios. Although you are building a home theater, the room could be used for gaming, for music listening, for dancing, for craft night . . . a variety of lighting options will extend the use of the room for the whole family. (Actually, you may or may not want to accommodate that!)

10. Take temperature into account. Electronics - especially receivers and amplifiers - throw off heat. Have a way for that heat to escape the equipment rack, and also to escape from the room. Overheating equipment can shut your whole system down.

There you have it! 10 things to think about before you begin. For more room-specific tips, check out Building a Home Theater in Your Basement which includes room shape, budgeting and more.

Special thanks to message board members nickbuol, chesseroo, exlabdriver, J.B., Hansang, Lampshade, Murph, bridgman, AdrianD, Ken.C, niveka , JohnK, INANE, tomtuttle, medic8r (ahem), fredK, MarkSJohnson and dakkon for their contributions to the thread!

Did I miss any tips that you wish you knew when building your home theater? Share them below!

If you've been listening to the same stereo speakers you got in high school, trust me - times have changed and sound has improved. Start with upgrading these first.

Get new speakers for left-and-right channel output first. Make sure they're large enough for the room they're filling. As a general rule, the further back you are sitting from the screen, the larger the speaker will need to be to give you a great sound experience. It's a matter of physics. Tiny speakers don't move enough air through them to produce realistic sound in a room with arched ceilings or large dimensions. Don't worry about getting speakers that are too big for your room though - you can turn them down in your receiver's set up menu if the output is too much.

Meanwhile, take those old stereo speakers, and move them to the effects channels, more commonly known as surround sound speakers. Place them behind the listening position and try to get them elevated at least two feet above your ears when you are seated, and somewhere between directly out to the side of you, or back up to about 20 degrees or so. This will place the surround effects where the producer of the album or movie intended the sound to fall.

You may notice that the surround sound doesn't always flow smoothly behind your head. This is common with direct-firing speakers. As you begin to upgrade your system, look at surround speakers that have woofers and tweeters on the sides as well as top and bottom of the cabinet. This multi-directional approach - referred to as quadpolar or dipolar - makes sound diffuse throughout the room, and creates a much more realistic surround experience.

Next, as budget allows, add a center channel. It's important that the drivers - the woofers and the tweeters - are of the same approximate size and material as your left-and-right speakers in order to create what is called a 'seamless soundstage' - that is sound that doesn't change as it pans across your front speakers. If a voice starts to the left of the screen and moves to the right, you don't want it changing tone or timbre as it goes. For the most realistic sound experience, buy your center from the same lineup as the front channels - otherwise you may hear the sound change as dialog moves from side to side.

Positioning is important when you're placing speakers in a home theater audio system, and especially so with a center channel. Ensure that the sound is reaching you at the same time from every speaker by placing it as close as possible to the screen. Try not to recess the speaker into a cabinet, or if you do, pull it forward when you are getting ready to watch movies or listen to music.

Finally, add (or upgrade) a subwoofer as your budget allows. If you've been using an old subwoofer from a home-theater-in-a-box setup, upgrading to newer subwoofer technology will create a very audible difference. Don't skip this step - most speakers lose output below 30 Hz - or you'll be missing out on the most thrilling parts of movies and music.Tight deep bass and sub-sonic sound simply isn't available in those small cube subs, or from bookshelf or tower speakers. A well-designed subwoofer adds realism by recreating the sound of a big drums, low rumbling explosions and more.

There you have it! A simple upgrade path to take you from stereo to a full-fledged 5.1 home theater audio system step-by-step.

Transmitting sound to your patio speakers

First, you need a pair of patio speakers. Ideally you'll mount them up under eaves or an overhang that allows them to be somewhat protected from the elements. Speakers that mount flush to the wall can be subject to vibration, so try to mount them on brackets that give them a little breathing space.

Bonus: not only will that reduce vibration, it will also help the overall sound of the speakers.

Apple Airport Express

Next, you need a way of transmitting sound to the speakers. If you've got speakers already wired to a receiver, pick up an Apple Airport Express Wi-Fi Base Station (around $99 at the Apple Store) and connect it to your internet connection wirelessly or by using an ethernet cable. Follow the prompts to get it set up, and then attach it to your receiver via an Audio cable.

Tip: If you're having trouble setting it up plug-and-play style, download Airport Utility to your computer and follow the prompts. It'll get you back on track in no time!

Set Airplay up on your network so that it is able to see the sound system you're using to transmit to the patio. You'll find it helpful to name the network according to location - eg Living Room, Patio, Sarah's Bedroom - so that you can easily select the right system when you're transmitting.

Once you have Airport up and running, download the "Remote" app from Apple and install it on your iPhone, iPod touch or iPad. This free application will turn your device into a wireless remote for your iTunes library.

Use Airplay for Outdoor Speakers

Launch iTunes and select the network name you gave your patio speakers. On the iPad, you first select the double-screen icon to indicate which network you want to join, and then you click on the Volume icon to control where the speakers are playing - on the system that iTunes is hardwired to, or on the system that you have networked in with your Airport Express.

That's it! you're up and running, with all your music and playlists at your fingertips. No need to wait for someone to go in and flip the record - you've got your entire digital library at your fingertips, and you can create awesome soundtracks for your patio speakers that will play for the length of your party.

How do you power your remote speaker systems? Tell us in the comments below!

A question on our Youtube channel this week inspired a little post to help you with audio troubleshooting subwoofers. No sound? No idea why? Here are 5.1 (naturally) tests you can try at home to see what the culprit may be.

1. Is it the coaxial cable itself? Test this by connecting your subwoofer in what's called the 'high level' way: use speaker wire to make the connection. If it makes sound, then it’s the coaxial cable that is at fault and you need to replace the cable.
2. Have you been rocking? Another common problem with subwoofer sound or lack thereof is that just from playing aggressively, or being knocked, or an earthquake, the lead could come off on the driver – either the positive or negative lead. To test for this, pull the driver out of the subwoofer to double-check that the positive and negative lead are still connected. If they are, continue your search. If one has come off, carefully reconnect it and test your subwoofer again.
3. Am I on? Test 123, test 123 . . . Unplug the coaxial cable from the receiver, but leave the other end so it’s still hooked up on the sub. Take the coaxial cable end that you just removed from the receiver and then tap it gently. If you get a thumping noise then you know the sub is working and the problem is the receiver. Which leads us to . . .
4. A little weather in your area? Most commonly, if there is a power outage, receivers will go back to the manufacturer’s default settings, so you have to go back to the setup menu and reactivate the sub within the receiver.
5. Straight from the source: You can take a source out of anything – such as a dvd player or cassette deck – that has a constant source, and plug it directly into your subwoofer. If you can hear thumping, you know it is working and your audio troubleshooting subwoofer test needs to continue. Thankfully, the last tip is a simple one:

.1 If there is no LED glow present, check your fuses!

There you have it - 5.1 common causes of home subwoofer sound problems.

5.1 Surround Sound = A Lot of Hiding!

How do you hide an entire 5.1 surround sound system?  Turns out there are lots of ways!  First and perhaps easiest, you can do what chameleons have been doing for centuries . . . just take on the same appearance as your surroundings!  Get loudspeakers finished in the same wood as the rest of your furniture, or take it a step further and use a paintable finish.

Paintable home speaker systems hide in plain sight.

By exactly matching your speaker to the wall behind it, you'll make it disappear into the decor and your sense of sound will become the dominant association with the speaker.  If possible, get a grille cloth that also matches your wall, or choose a speaker with a paintable grille so that you can continue the camouflage effect.

Another way to hide a home speaker system is to use a built-in wall or freestanding entertainment unit that lets you build the speakers right into it.

In these installations, the speakers are completely enclosed in the unit but sit slightly forward to remove any unwanted sound artifacts from the furniture or wall.  A grille cover and a paintable surround mean that you can make the speakers disappear into the wall or unit, providing a clean, seamless look across the front of your entertainment area.

In-Wall or In-Ceiling

Ceilings are a great option for hiding home speaker systems.

If coordinating your speakers isn't going to meet with enough design acceptance,  look for an in-wall or in-ceiling speaker so that you can enjoy great surround-sound without compromise.

A few considerations when you're putting speakers in the ceiling: the best-sounding speakers have enclosed backs so that you don't need to worry about what is behind or above the speaker.  When you have a speaker with an open back, it makes the entire ceiling or wall space it's enclosure, and that can lead to some strange sound reflections that just make your system sound bad.  What's worse - there isn't anything you can do to correct the problem once the speakers are installed.  Instead, choose speakers with a full enclosure as part of the engineered design so you know they'll sound the way the speaker designer intended them to, no matter where you put them.

Also, be aware that sound travels!  If the baby's room is above your living room, in-ceiling speakers might make the sound too loud for sleeping.  If that's the case, look for in-wall speakers instead.

Finally, It Almost Goes Without Saying, But . . .

Gimmicky home speaker systems designed to look like knickknacks?  Probably not using 'great sound' as a design parameter!  Ditto 'folding origami speakers' - sure, transducers produce sound, but at 1 watt . . . it's suitable for novelty effect at a dinner party but not for home theater playback!

High-end home theater speaker systems can be literally hidden in plain sight now - get the sound you've been craving without the compromise!

1.  Check The Settings:  Ooooh boy, is this a can of worms!  But if you've left the remote control in the hands of guests while you toddle off to bed, or (worse) in the hands of teenagers while you toddle off to Niagara Falls with the inlaws . . . who knows what settings you are on.  Most modern receivers offer a one-click double-check that will play test tones through your home speakers.  Are they all plugged in and working?  Is the level roughly equal?  If you have time, check the levels with an SPL meter  (either one you hold in your hand or one you download to your tablet).  You'd be astounded how often things are 'turned off' by someone accidentally sitting on a remote control . . .

2.  Check The Source:  Are you streaming the lowest-possible quality from your movie provider?  Try playing a blu-ray or high-quality DVD and see if that might be the culprit.  Often what seems like a 'little' compromise to get faster downloads or to conserve bandwidth is actually affecting your whole movie experience.  A simple test with an old classic piece of physical media that you have hanging around your entertainment unit could give you the answer you're looking for.

Ideal placement: the home speaker triangle.

3. Play With Placement:  Sometimes all you need is a just a step to the left . . . or a jump to the ri-i-i-ight . . . if your speakers have been moved by well-meaning vacuumers or rambunctious pets.  Measure the distance off with your feet or a measuring tape.  The ideal separation is to form a triangle between your front, left and right home speaker and your seating area that is equal on all sides.  If there are 15 feet between your seat and the speakers, there should be 15 feet between the front speakers as well, forming an equilateral triangle.  This applies to the center channel, too - don't bury it in a shelf or inside a cabinet, or if you do, pull it slightly forward of the shelf or cabinet when you're watching a movie and hear the sound open up.

4.  Pigeon-toed or Bow-legged?  Either one might create a noticeable difference in sound in your installation.  Invite a friend over (ply them with promises of delicious beverages and amazing popcorn!) and have them move the speakers in or out slightly while you listen to well-recorded tracks you're familiar with.  When speakers are 'dialed in' correctly, the soundstage will open up and your listening room will fill with more life-like, less compressed sound.  Don't limit your experiments to side-to-side, either:  pulling speakers slightly forward of the video display can really bring them to life as well.

5. Get Rid of the Odd Man Out:  Your 1971 college speakers brought you much joy back in the day and you've kept them around as souvenirs of great times . . . and that's fine if they're end tables or bookends, but not if they're your primary surround speakers!  So much information is transmitted through the surround channels now that you're really doing your system a disservice if you wimp out on the effects speakers.  Look for modern home speaker options that have quadpolar technology in order to get the most vivid, realistic experience possible.

What tips do you have?  Do you have any tips for improving your surround sound experience?

If you've been thinking about starting one of these societies in your area, I highly recommend it!

Give me a little space baby!

If you're considering on wall speakers to go with your flat-screen plasma or LCD display, you may be wondering if there are any special placement considerations you need to take into account, or if they can go just about anywhere.

On Wall M3 Speakers pictured in our Real Wood Rosewood Finish

I spoke to Audio Expert Brent Tombari to find out what he recommends.

"Many people pair on wall speakers with large 40 or 60-inch displays.  My recommendation is to mount the speakers as closely as possible to the edges of the screen in order to fill the screen area with sound."

Basically, we are trying to create the illusion that you are in the action, and in order to do so you literally want the voices to come from where the picture is emanating.  By placing on wall speakers for the front left and right channels directly next to the TV screen, that illusion is more convincing.

"The same goes for the on wall center channel.  If possible, mount it as close to the bottom of your television screen as it will go.  This creates a more realistic sound experience."

(As an aside, we don't recommend mounting the on wall center channel above the screen unless that is your only option, since the center cannot be pointed 'down' toward the listeners.)

Brent refers to Axiom's on wall speaker series as a great option for Canadian and other colder-climate customers who have their televisions mounted on an exterior wall. "Drilling into an exterior wall to recess in-wall or on-wall/in-wall speakers breaks your vapour barrier and compromises your insulation factor," he warns.

Using on wall speakers for stereo instead of as home theater speakers?  Then the usual positioning rules apply:  start by trying to form an equal triangle between the main listening seat and the left and right channels.

Remember, these are ideal placement guidelines:  your ears will tell you what sounds best to you, in your room.  Don't be afraid to experiment: round up some friends to hold the speakers in place with music playing and move them to your ideal position.  See where they sound best to your ears, and then get out the drill.

Check out pictures our customers have sent in of their on wall speaker installations.

First Things First: The Classes

It's impossible to understand what the choice before us is without understanding the different classes of amplifiers.  We turn to our guru, Alan Lofft, who explains in an article elsewhere on this site entitled Ten Things You Always Wanted to Know About Amplifiers :

How Do They Work?

In looking at different amplifier designs, we need to consider the modes in which transistors can operate.  When a transistor is operated as a switch, it’s either fully off (cutoff) or fully on (saturation).  When the transistor is in either of those states, it’s very efficient – there are almost no losses in the transistor.  But if it’s operated in a Class A/B amplifier, in the forward active mode, the transistor is always conducting current, even when there is no audio signal.  For this most common of amplifier types, the output transistors are essentially always being used, and therefore giving up energy to heat.  The more current that flows and the more power that is delivered to the amplifier, the more heat that gets generated.

In a Class D amplifier, the transistors are never used in the active mode like a Class A/B  amp.  They’re used in a switching mode where they are always fully off or fully on.  This means you can theoretically get nearly 100% efficiency, because the losses are very small.

The problem is how do you switch a transistor or a couple of transistors on and off to create a sine wave?  Simply switching them on and off gives you a square wave.  But if you look at a sine wave, it goes gradually from zero to positive, then back to zero, and then gradually becomes more and more negative, and then back to zero again.  So we need to get the transistors to create a sine wave instead of a square wave.  How do we do that?  We turn them on and off at a constant rate, between 300,000 and 400,000 times per SECOND.

Next, we have to somehow make those transistors that are switching on and off at extremely high speeds  recreate a sine wave or a music signal.  To do that we use a technique called Pulse Width Modulation or PWM.  All that does is look at the input signal – the sine wave, for instance – and depending on how positive or how negative the signal happens to be, we change how long the transistors are on and off.  If there is no signal coming to the amplifier the wave is steady and regular, like a clock.  When we send a signal through, though, what happens is the amount of time the positive or negative transistor is on changes with how positive or negative the input signal is.

Here is an image showing how pulse width modulation reproduces sound. Original image is borrowed from http://en.wikipedia.org/wiki/Pulse-width_modulation and slightly enhanced.

Let's look at the image to the right. In the top part you can see a sine wave in red.  In the lower part of the image, the purple series of rectangular sections, the little rectangles are changing in a manner that perfectly mimics the sine wave. We then use this PWM modulated version of the audio signal as the control signal that varies the timing of the output transistors turning on and off.

So we now have a signal at the output of the amplifier that contains the information about the sine wave that went into the amplifier.  Next, we apply a filter to get rid of all that really high frequency stuff that happens beyond the limits of human hearing (that fast 300-400,000 times switching signal).

Even though the output stage is not directly tracking the input signal, those transistors are always operated either fully off or fully on.  Because of this they’re always operating in their highest efficiency area, unlike a traditional amplifier.

In effect, we’re just operating the devices that produce the power in an area where they are far more efficient, and hence the whole amplifier can be more efficient.  It’s generating less heat and it wastes less wall power. At its most basic, we can illustrate efficiency by taking the example of drawing 100 watts from a wall socket. In a Class A/B amplifier we can get about 50 watts from the amplifier to deliver to the speaker.   As you know from your high school physics class, the other 50 watts has to go somewhere, so it becomes heat.

With a Class D amplifier, you draw 100 watts out of the wall and you get 90 delivered to speakers.  The importance of this goes far beyond the obvious savings of electricity: it adds greatly to the performance of your system.  We all seek a dynamic performance without distortion and the way to achieve it is to have enough power in your amplifier to reproduce those dynamic peaks, which require large amounts of power for short periods of time, without limiting or clipping.  An efficient amplifier with a large power supply can do exactly this, and that was the design goal of our Axiom amplifiers.

Now, since most of us have to pay for our electricity, and since most of us don't want to go to the expense of adding a 20 amp circuit to our house to get more power to our home theater speakers, a more efficient amplifier means you can maximize the power to your home theater system by using as much of the power coming from your wall socket as possible to move the drivers on your loudspeakers.

Hopefully this long explanation helps you understand the different amplifier designs and why Axiom has chosen a Class D design for its new home amplifier lineup.

Elsewhere in his home is an on-wall M22 system with an on-wall VP150, and two pairs of Algonquin Outdoor Speakers. Read his impressions of his in-cabinet home theater system on our message boards.

Some of you may already know this about me from chatting on the phone or via email: when it comes to music, I love the blues.  And when I choose blues speakers, I choose Axiom :)  Recently I had the opportunity to offer a pair of Algonquin Outdoor Speakers to a member of the Sault Blues Society, an organization that I'm a member of.  I also sit on the steering committee.

It's a great club.  If you live near Sault Ste. Marie or are planning a visit our way this summer, mark your calendars. Our First Annual Blues Festival is June 8 & 9.

The Sault Blues Society is an incorporated not for profit organization that has been established for two years.  The objects of our organization are:

• to organize a Blues festival,
• to create additional performance opportunities for local musicians
• to provide a venue to have listeners and musicians of the Blues to share their knowledge and experience
• to educate the people of Ontario about the diversity of the Blues,
• to partner with other organizations and associations to support and further common goals

We will be holding our First Annual Blues Festival at the Algoma Water Tower Inn on June 8 & 9, as well as one other fundraising event on May 5. The Algoma’s Water Tower Inn has been one of the Sault Blues Society corporate sponsors since our inception.

We currently have 98 members, I have been a member for 2 years and joined the steering committee the last year. You can learn more about us here:   http://www.saultblues.com/index.html

Our next fundraiser we will have Al Wood and the Woodsmen an Ottawa Based Blues Group performing at the WaterTower.

Our first annual event will be a 2 day venture, June 8th & 9th, at the WaterTower Inn, featuring Steve Strongman, a gifted blues guitarist out of Hamilton and The David Rotundo Band , a vocalist/harmonica player based out of Toronto.

Any other blues fans out there?  Post your current favourite artists below!

Another thing has had my curiousity piqued about the LFR1100 omnidirectional speaker . . . what's with the angled backs? Granted, the angle is slight, but the rest of our speakers have straight backs. What gives?

I tracked (okay, hunted) Andrew Welker down and asked him the question. His reply:

Well, basically any sound coming from the back of the speakers is going to reach the listening position as a reflection of some sort. (The front section, by contrast, has a high proportion of direct signal pointing directly at the listening area). So we're relying on reflections off boundaries for the sound, and for the most part boundaries mean a back wall.

If you imagine most people's home theater set up, what would be between the two speakers in their home? Probably a TV, a credenza, an equipment rack, and so on. If, for example, you were to place your speakers without toeing them in at all, we have a situation: the signal is firing directly at the rear wall, and will create reflections bunched up between the two speakers where the TV, credenza or whatever may be.

By angling the back, even if you have the fronts set up firing straight ahead, it's forcing the reflections to fire to the left on the left speaker, or to the right on the right speaker, instead of bunching up between the two speakers. By spreading out the reflections in terms of width, we get a larger, more open soundstage from which to work. And after all, that's one of the main reasons we have drivers on the back of the speaker to begin with.

Although we're not the first to do it, it is still fairly atypical in speakers, and a first for Axiom's line up.

I hope that helped you as much as it helped me! Do you have other questions about the design and engineering of the LFR1100s? Post them in the comments below!

Axiom's Audio DSP

The DSP is an integral part of the LFR1100, and why we sell it as part of the set. It serves two main functions:

1. The first function is applicable to any speaker - to the LFR1100 or any of our products. When you use a traditional passive crossover network (not wall-powered but rather passive in that it uses capacitors, inductors and resistors), we are limited in how precise and how detailed we can get with those passive crossover networks. We can do a good job of getting the overall frequency response linear, both on-and off-axis, to get the Axiom Listening Window to look the way we want; however, the problem in a passive crossover is that you can’t correct every area. The idea of the LFR1100 is to correct every little peak, dip, hump or null to create our most accurate speaker yet, with the added benefit of an expansive, yet accurate, soundstage.

So the main thing the DSP allows us to do is to take a speaker with a passive crossover and go the extra mile with the DSP to correct all those things which we can't make absolutely perfect, particularly when we go off-axis and we want the family of curves to look a certain way. Because we're dealing in the passive world we're dealing with part restrictions. There are not an infinite number of parts available, and to attempt to address this level of sound detail passively it would take well over 100 parts to get it right. By way of contrast, a normal passive crossover has 4-15 parts.

Using an audio DSP makes all of the curves look textbook-perfect on- and off-axis. It takes a good design and makes it that much better. (Aside - we'll be making it available for the M80 and the M60 in time).

We're applying that correction to both the front and back sections of the LFR.

2. Additionally, in the case of the LFR, the function of the DSP is also to make the rear drivers 'play nice' with the front drivers.

The LFR1100 speaker pictured front and back

Let’’s assume that you have the front section of that LFR system measuring the way you want it to and sounding really nice. Now we add in the rear drivers. Even though on their own the rear sound is as accurate and flat as a good speaker on its own, (in fact, in the case of the LFR it would sound quite similar to the M22 bookshelf speakers – note the configuration), when you add the front section of the speaker to them, you get some pretty bad interaction between the front and back sections.

Part of the reason is that they are separated by a distance - the depth of the cabinet in this case (17 inches) which creates a bit of a delay in the sound that comes from the back drivers compared to the sound coming from the front drivers. You'll not only hear it in your living room, but it is also clearly seen in the anechoic chamber.

This cancellation has been the major issue with the majority of bipolar-style speakers. At some frequencies, the sound from the back of the cabinet wraps around the side of the cabinet and combines with the sound from the front of the speakers. This cancellation phenomenon gives the speakers the really big sense of space that is the biggest feature of that family of speakers. However, those same interactions tend to distort the tonal balance, which can be especially heard in the midrange, making them not very focused and somewhat distant.

Where that cancellation typically takes place is also in the particular frequency range which helps us in our mind create the 'image' - a location of where the sound is coming from. In a typical bipolar with these cancellations, the image gets very washed out and indistinct.

Also, a point of clarification for those of you who have been asking: Bipole is defined as the front and rear sections are operating in phase with each other. A dipole, by contrast, means the front and rear sections are out-of-phase with one another, and that is not what we're doing with the LFR1100.

Unlike what we can do with a passive crossover, we have far more freedom with the corrections we can do digitally. In the case of the LFR, we want to adjust the frequency response of the back section so it’s no longer actually flat. If you were to look at graph of just the back drivers, it would look strange: but that’’s because it is specifically designed to avoid those cancellations from taking place. Instead, what we’re trying to do is to tailor the frequency response of the speakers so you don’t get those cancellations. We’’re making the character of the front section sound the same, with or without the back drivers.

It’’s a complex piece of engineering and coding – hundreds of hours in all – that you simply couldn’’t perform with a passive crossover: the sheer volume of parts would start to negatively contribute to the sound of the speaker and waste a significant portion of your amplifier’’s power.

I hope that helps you understand just what the LFR1100 audio DSP is doing as well as it helped me! Stay tuned (pun intended) for more posts on the inner workings of our latest speaker.

Home Theater Shack has just released their review of the Epic Grand Master On-Wall Home Theater Speaker System.  The system earned a Home Theater Shack Reviewer's Choice Award!

Reviewer Dale Rasco critiqued the system, saying:

"In my opinion, the Axiom on-wall series provides a rich audio presentation combined with a sleek and modern look without sacrificing overall fidelity. They are the perfect blend of fit, function and finesse while still being financially viable for the average enthusiast."

Also included in the review are direct comparisons between the sound of the on-walls vs his larger Epic 80 - 800 set up, and what happened when things really started to get rocking, during a listening session with Symphony X.

The system was reviewed in Vermont Maple Custom Vinyl, earning Rasco the coveted "Better Half Approval Vote".  To see pictures of the system, click on the images below.

Read the full review here:  http://www.hometheatershack.com/forums/speaker-reviews/56820-axiom-grand-master-5-2-home-theater-system-review.html#post513860

Andrew's brother-in-law Tim Nadeau kindly provided us with photos from the show to share with you.

Here's a quick video of the room we were in:

And an interview we did with James Tanner of Bryston on the BDP-1 Digital Player

When you measure a loudspeaker in the anechoic chamber, he explained, you will see a certain frequency response when the front baffle is facing straight-on to the microphone. As you rotate the speaker in degrees - for example, 15 degree increments - the amount of reduction in energy from the tweeter should remain consistent. An angling of x degrees and a reduction of x decibels, as it were.

In a conventional speaker, however, by the time that angle reaches 60- 90 degrees, there is a very rapid reduction in upper midrange and high-frequency energy. So it might appear nice and even to 90 degrees, but as you go further than the 90 degree angle, the highs really begin to disappear. Ideally you'd like for this energy continue reducing in level in an even fashion, but this is nearly impossible to achieve with drivers only on the front of the speaker.

So how to compensate for this problem? Well, the theory is that if you put tweeters and mid-woofers on the back of the cabinet, you can keep the energy consistent across a wider frequency range, increasing the spectrum of sound being radiated throughout the room.

But the challenge has always been that if you put identical drivers front and back, you introduce some nasty cancellations between front and back. If you heard early versions of omnidirectional speakers, you know what we mean.

Enter the DSP. By using a digital signal processing chip, you can code the exact response of the speaker to eliminate these cancellations, and create what we like to call the Axiom Listening Window - smooth frequency response across the family of curves. What that translates to is even energy in the highs and midrange, along with the detail and image focus that Axiom speakers are famous for. Got a home theater with 6 seats across? How about a big sectional couch? Imagine if everyone heard the same wide soundstage that you enjoy in the sweet spot.

The goal of the new Axiom Omnidirectional speaker is to create our most realistic, enveloping speaker to date. Applying the latest developments in DSP technology to a solid foundation of research in loudspeaker design has created a truly unique speaker worthy of being called Axiom's new flagship speaker.

A recent article in the San Diego Union Tribute said that among the most frequently-requested features in a new home are home theater rooms. The article speculates that it is because there is so much technology now that we need a place for all of it to converge. I think it's so much more than a convenient place to store gadgets and gizmos, though: for most of us, it's our own portal to another place and time. Think about it: how many other rooms in the house are there exclusively for pleasure, and for relaxation?

How do you make your home theater rooms appealing to future buyers? The article suggests you hide all your wiring, and you choose 'less' furniture over 'more' to make the space look bigger.

I'd like to add a few more tips:

• Have several lighting options available. Although perfectly dark cave-like home theater rooms are ideal during a movie, what about when you're getting settled in? What if you need to pause the movie while someone refreshes the beverages or takes a bio break? Do you have to throw on full overhead lighting, or can you take advantage of the numerous rope lighting or under-counter lighting options, or even just good old fashioned dimmers, to give you plenty of options for your media space.
• Consider all the uses of the room, not just movie-watching. Is there a social space like a wet bar or counter with stools for people just looking to sit and chat and listen to music? What about enough space in front of the seating area for active games of Kinect or Wii? Can people easily come and go from the room without having to trip over other movie-watchers (although admittedly, this would provide authenticity and increase the 'movie theater' feel of the room!)
• Take advantage of today's high-end home theater offerings to choose in-wall or in-cabinet speakers where appropriate, or if you have a lot of space, look at custom matching options or paintable speakers to create a really unique and personal home theater look. If black boxes don't inspire the decorator in your home, don't despair: there are plenty of options out there!
• Although glossy home theater magazines are fun to look at it, search out other pictures of home theater rooms to give you real-world ideas for your special space. You'll be amazed at how creative people are, and you may just be inspired to try something unusual in your room, too!

It's exciting to see the growing interest in home theater rooms. With all the technology currently available to us, it's great to have a place in our homes where we can experience the pleasure of a truly interconnected experience.

---

Source: San Diego Union Tribune, March 5th: HOME THEATERS: DESIRED BY HOME SHOPPERS

Coming soon to a salon near you . . . Axiom will be demonstrating its 'top secret' new stereo and home theater speaker at the 25th annual Salon Son et Image in Montreal, Quebec, Canada, March 23-25th.  The speaker, over 10 years in the making, is a combined effort of Axiom president and founder Ian Colquhoun, and engineer Andrew Welker.

Also at the show, Axiom has been invited to participate in a panel of six of North America's best speaker designers.  Andrew Welker will represent Axiom on the panel on Saturday.

Axiom will be co-exhibiting with Bryston, makers of industry-leading professional and commercial specialty electronics.

The show average around 8000 visitors each year - more than Axpona, RMAF and TAVES all combined together - and it brings together some of North America's most discerning customers and reviewers, both home theater speaker enthusiasts and stereo-only audiophiles.  It will take place at the Hilton Bonaventure Hotel Downtown Montreal for the third year in a row.

For tickets and more information on the show, please see: http://www.salonsonimage.com/EN/index.html or http://www.salonsonimage.com if you speak French!

Introducing the latest Axiom Home Theater Speaker System: The Epic 60 600 160. Oh yah, that's a lot of numbers! Take the award-winning M60 floorstanding speakers, add the deep-as-the-ocean EP600 dsp-powered subwoofer, the critically acclaimed QS8 surround speakers, and then add our new commanding VP160 center channel. Theresult? A home theater system so perfectly matched and deeply powerful that you'll be forgiven for not leaving your house all weekend!

The new system is custom-configured for dedicated home entertainment areas. The advantage of larger speakers over smaller ones is immediately apparent when you hear the system: suddenly sound becomes spacious, and a new dimension is added to your movies and music. You are immersed. You are surrounded. You are part of the experience.

"We relentlessly pursue the most exciting audio experience we can provide," said Axiom founder and chief engineer, Ian Colquhoun. "Bigger speakers mean more emotion, more thrills, more explosions, more romance, more excitement. The bigger the cabinet, and the wider the range of frequencies you can provide to the home theater listener, the more realistic their experience will be."

The home theater speaker system can be ordered in standard Boston Cherry or Black Oak, or it can be customized in any of our hundreds of finish, stain and grille possibilities. Custom painting to match your walls is also available on this system.

We can't wait to read your reviews of the new Epic 60 600 160!

1. Power: without enough of it, your gametime audio is like a quarterback who forgot his Wheaties. Make sure you you have enough amplifier power to do justice to the speakers. Not sure how to tell? Most manufacturers publish at least a maximum amp power - try to get as close to that as possible. Axiom publishes a minimum power as well, so make sure you have at least that much power going in! Tip from the Secret Playbook: The bigger your room, the closer to the maximum amplifier you should be to get that won't-watch-the-game-anywhere-else-every-again experience.
2. Play: Make sure you're not using a stereo receiver - or worse, your TV speakers - when the big game is being broadcast in Dolby Digital. The National Football League led the sports charge with the first high-definition surround-sound broadcast with the 2000 Superbowl. All NFL games and most other sporting events are now being broadcast in 5.1 surround sound - don't miss feeling like you're right in the audience. Nothing is as authentic as hearing a heckler coming from right behind you with Superbowl audio providing the calls.
3. Positioning: Is your home theater set up properly? Have you taken the time to do the subwoofer crawl? Ensure that your front speakers form a triangle with the 'sweet spots' on the couch: your front left and right speakers should be the same distance from the seating position, and slightly forward of the center channel. The distance from the right and left speakers should be equal from the center channel. Tip from the Secret Playbook:If your center channel has gotten shoved to the back of a shelf, pull it slightly forward over the lip of the shelf for the big game (really for every time you listen, but I understand the wife vote!) to get the clearest dialog. Need to invert your center? Check out our center channel placement video here.
4. Proper Balance: Make sure all your speaker levels are balanced properly. Sometimes curious fingers get playing around in the menus and suddenly one channel is turned way down. Check the on-screen display and if you have SPL meter, run pink noise through your speakers. Check out this great superbowl sound must-have app if you don't.

One of the best parts about the holiday rush of speaker orders is reading the feedback on our message boards, Facebook page, Twitter Account or emails from new owners. The descriptions are sometimes an echo of exactly what we've felt but never been able to articulate.

When Message Board Member SocketMan got his M80s installed, he made a great post entitled "My Condolences", and posted "I have to say i truly feel bad for anyone who has not had the opportunity to hear the M80's. I have only listened a little bit,but i can say i have never heard Pink Floyd , the wall like this before. Dont even get me started on metallica,im hearing things i didn't know where there."

His talk of the first songs he listened to made me curious: what songs do you immediately use when testing loudspeakers?

At Axiom, it's hard to drop in for even a minute without being plopped down in the listening room and being handed a switching box and a clipboard. I always go for what I know: a little Holly Cole with beautiful high notes and the satisfying thwang of a stand-up double bass in "I Can See Clearly Now", some Bob Seger with soaring nostalgic notes, and if I've had notice that I'm going to be listening, the soundtrack for Master and Commander featuring Yo-Yo Man's incredible cello playing.

When Alan Lofft tests loudspeakers, he also starts with Holly Cole:

"I usually start with the Holly Cole CD in the listening room, Don't Smoke in Bed, and use "I Can See Clearly Now" and "Every Day Seems Like a Holiday" tracks.

Then I switch to a big orchestra/choral work, "Sea Symphony" by Vaughan Williams, a great test of choral and orchestral detail and spatial presentation.

I follow up with a one or two tracks of Harry Connick Jr trio, soundtrack of When Harry Met Sally, "Love is Here to Stay" and "Let's Call the Whole Thing Off". Great neutral male vocal and jazz trio recording.

Sometimes I play Dire Straits' Brothers in Arms, "Ride Across the River", an excellent rock recording with very deep bass."

For Brent Tombari, testing loudspeakers means cueing up "Ascent/Also Sprach Zarathustra" from Time Warp- Cincinnati Pops Orchestra; "The Panther from The Well" - Jennifer Warnes, and "Cha Cha Loco" from Focal 3 - Joe Jackson.

And for engineer Andrew Welker, it's "Hello City" from Barenaked Ladies’ Gordon, "Don’t Let the Teardrops Rust your Shining Heart" from Holly Cole’s Don’t Smoke in Bed and "Isn’t It a Little Late?" from Eleanor McEvoy’s Yola.

What are your go-to tracks when you're testing loudspeakers? Any surprise notes in a song you'd listened to hundreds of times before?

Choosing the best front speakers for your room can seem overwhelming at first. There are so many variations of the traditional stereo speakers that you can't be blamed for yearning for the early days of one-size fits all brown wooden speakers with bright orange woofers.

Don't despair: help is at hand! Here's a guide to today's loudspeaker formats and how to choose the best ones for your room.

First, the big boys: floorstanding speakers. Also called tower speakers, these larger models don't need stands and they don't compromise on sound, either! The large array of drivers (woofers and tweeters) mean that the full spectrum of sound is reproduced, and the larger cabinet means larger volume and that translates into more sound at high levels. It's a matter of physics.

If the room you're placing the speakers in has vaulted ceilings or is open to other rooms in the house (say a combination living/dining/kitchen area with no walls in between) then you'll want the power and volume available in floorstanding speakers.

Next, bookshelf speakers, the all-arounders. These much smaller speakers can be placed on stands, in bookshelves or mounted to the walls. There are almost as many variations of these speakers as there are kinds of apples in the supermarket! At its most basic, a bookshelf speaker has a tweeter and a woofer, designed to reproduce high and low notes, respectively.

Bookshelf speakers do best in rooms under 2,500 cubic feet (length x width x height of the room). If you have a medium-sized closed off family room, den, or bedroom, this is a good choice for you. A great all-rounder you may want to consider is the Axiom M3 front speakers, which reproduce the full sound range without the need for a subwoofer.

But wait - they don't only come in stand-alone models! Compact bookshelf-sized speakers also come in in-wall, on-wall, in-wall/on-wall and outdoor configurations! Here's brief rundown of which to use where:

In-Wall Speakers: these speakers recess into the wall as their name suggests, and normally includes a paintable grille so that you can literally make the speaker disappear into the room. The best ones are sealed off so that the sound output is completely controlled.

In-Wall / On-Wall Speakers: If you'd like your speakers to still look like speakers, but not to extend past your flat-screen display, an in-wall/on-wall front speaker is the way to go. These speakers have a narrow box that goes into the wall and lock into a bracket to keep the speaker in place while it's playing.

On-Wall Speakers: If you're renting your space, or if the material you're mounting the speakers on is not conducive to cutting holes into the wall, consider on-wall speakers. These small front speakers are entirely enclosed on the outside of the wall, allowing you to connect them with flat speaker wire which can be painted or papered over for an invisible look.

Outdoor Speakers: As their name suggests, these speakers are designed to be used outdoors and can be left out regardless of the weather. Don't be fooled by novelty enclosures: the laws of physics hold true and you need a speaker that has enough physical volume to transmit sound that can be heard over traffic, swimmers, or other outdoor noises. Axiom's outdoor speakers can be custom-painted to match your home's siding, your patio furniture, or whatever you like.

I hope this article gives you a good overview of all the possible configurations and when to use which ones. To get started choosing your front speakers, visit our products page or contact us.

Guru 3D has finished their review of the EP125 8-inch 125-watt Powered Home Theater  Subwoofer and given it a Guru Recommended Award!

Reviewer Steven "ROBSCIX" Wall recently added the EP125 to his two-channel computer speaker system (see an earlier review of the M2 Bookshelf Speaker on Guru 3D here) and he was impressed at the musicality of the subwoofer.

Wall has long been an advocate of upgrading your computer speakers to match the quality and potential performance of your computer, and employing proper home audio speakers to add realism to gaming and online movie-watching.

"The EP125 sub impressed us with seemingly effortless ability to produce clean, clear, accurate bass that doesn’t muddy or blanket the rest of the spectrum while performing at relatively high volumes.

If you are looking for a high quality entry level product for your bedroom or smaller rooms, we suggest having a listen to this sub and decide for yourself after hearing this unassuming unit muscles up some great bass!"

Read the full review of the EP125 Powered Subwoofer here.

We're thrilled!  SoundStage has announced their annual Product of the Year Awards, and the Axiom Epic80-800 Home Theater System won for Outstanding Performance!

Announced annually at the Consumer Electronics Show in Las Vegas, the awards are given out to products in each of four categories:

• Outstanding Performance
• Exceptional Value
• Aesthetics and Sound
• Pioneer Design Achievement

Axiom's Epic 80 - 800 was reviewed by long-time  SoundStage Network  reviewer Vince Hanada, who said "Its level of performance was intoxicating, and left me shaking my head in disbelief."

See more about the awards here:  SoundStageNetwork

photo courtesy SoundStage! Networks