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.

Click to enlarge the subwoofer amplifier

One look at the back of a subwoofer amplifier and your first thought might very well be “Yikes!  What did I sign up for?”  But relax – while each knob, gizmo and switch does have its own job, it’s easy to understand what they do once you hear an expert explain it to you. Listen as Andrew Welker, Axiom Design Engineer, explains the Axiom subwoofer amplifier settings.

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.

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.

http://www.youtube.com/watch?v=xTlGrydWAcA

Today, Axiom Engineer Andrew Welker discusses how to hook up dual (or multiple) subwoofers.  We often recommend that customers who are looking for a smooth, even bass response at every point in their home theater room look at adding a second (or more) subwoofers to the room.  What this does is even out any peaks or nulls in the room that can occur at seats other than your own.

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!

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If One Sub is Good, Are Two Better?

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.

The stands are 40″ tall, and easily hold his 10-lb speakers without wobbling.  He suggests that if anyone was worried about wobbling,  ”One idea would be to use that quick-release picture frame stuff by 3M to attach the top section to the wall.”

Check out the custom speaker stands here!

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