Axiom Home Page Forums General Discussion Home Theater Understanding Tech Specs on A/V Equipment

A lot of people are looking for the latest and greatest Home Theater addition and are always comparing different Speakers, Receivers etc... to other brands but are often mislead by the Tech Specs and other claims made by them.

I would like to discuss any questions people may have regarding the understanding of those Tech-specs and how to compare them to other various brands. To make the most informed decision possible before purchasing A/V Equipment. And getting the most bang for your buck as we all strive for the Ultimate Home Theater that we can afford.

Including:
S/N & SPL Ratio's
Power Output RMS WATTS
Freq-Response
THD (Total Harmonic Distortion)
Design
ETC....

For example: Onkyo TX-NR828 Receiver

This receiver claims that it produces 160Watts @ 0.7Thd
however upon closer review we see that this is with only
2-Channels driven Simultaneously. So exactly how much power
are you getting when driving All-Channels Simultaneously?

In this case Sound & Vision Magazine did a Test Bench and
shows you just how much power your really getting to those speakers.

5 Channels Continuously Driven, 8 ohm loads (.1 THD) 109.9 watts
7 Channels Continuously Driven, 8 ohm loads (.1 THD) 78.5 watts

That's a loss of over 80 Watts per channel.
This is why it's so important to understanding Tech-Specs

Look for companies that test ALL-CHANNELS DRIVEN such as Emotiva & Axiom
which make some of the finest Power-Amps anywhere for amazing prices.

Sources:
http://www.onkyousa.com/Products/model.php?m=TX-NR828&class=Receiver&source=prodClass

http://www.soundandvision.com/content/onkyo-tx-nr828-av-receiver-test-bench

[img:center]http://www.soundandvision.com/images/styles/600_wide/public/913onkrec.prmo__0.jpg?itok=IEBRcf8l[/img]

Hey Alaskan,

There's been many discussions of many technical subjects over the years on these forums.
Some are much like beating dead horses 15 lives over.

Aside from that, Axiom puts out a newsletter every so often and includes technical articles on, well, all of these things and has also done so for many years now.

People can (and have for some time), accessed this info at the Axiom pages dedicated to it.
You might want to have a look. Many folks on the forums are not new to these subjects.
http://www.axiomaudio.com/guides

Apparently not many have read them, so I created a discussion forum to discuss the Fundamentals and Industry Standards. As I found out on other Forums that not everyone is aware of as I do not see these Topics being discussed on a regular basis. And their points are contrary to these very Fundamentals.

So please if you have anything to add to the Forum Topic at hand please do so. It doesn't matter how much you know i'm an Audio & Videophile but we should still practice our Fundamentals because those that forget history are doomed to repeat it.

This is for Audiophiles & Newbs alike to help eachother out.

I know who you are !!!

You need only change your sig to
"REFLECT but verify"

YOU HAVE NO HONOR.

Settle down now Children were discussing: Understanding Tech Specs on A/V Equipment here only. Stick to the Topic.

I would give this about 1 more hour before the thread is horribly hijacked by beer speak and what the wife did to the kids today.

Just a heads up.

The wife gave the kids beer today!

I give Tom about 3 minutes to respond with the most likely following question:

Which beer was it?

No, really, i'm being serious.
I think he will.

Hey Alaska,

I don't understand what you mean by losing 80wpc?

When you drive more than 2 speakers, isn't the theoretical net Spl increase on more channels driven making more efficient use of the total watts available in each circumstance? Since the first few watts do most of the work I understand.

Even if it means only driving each channel with a max of 80w x7 vs 160w x 2?

The net output is much increased, no?

It was Sierra Nevada Torpedo. They liked it.

But I'm really the only one in the house that seems to like Belgian beer much. So, I need Peter and Ken to come over more often.

My wife has been making pulled pork in the crock pot (gasp!) and while it obviously doesn't have the smoke component, it's ease of preparation means I get to eat it more often. In conjunction, I've been tarting up bottled BBQ sauce with apple cider vinegar and whatever else jumps off the shelf. Satisfactory!

So far so good on the Bosch dishwasher, btw.

Recently viewed the Zeppelin Celebration Day video and was really impressed with the production.

Cheers.

Did i say 3 minutes to respond?
I meant 53 minutes.

Now ya gone and done it...

Hey Tom. You forgot to tell us what colour shorts you were wearing when you dropped the top on your car and drove about town with your hair blowing in the breeze.

OK, now seriously, what the heck would I do with 180 wpc all channels driven when most of the time my power draw is less than 2 watts to make my ears hurt? Well, if my name was Ian I could throw a party on my dock and play music for everyone on the lake, but its not and I can't.

I used to know all those numbers, but really, it doesn't matter. As long as I have a reasonable amount of power and I don't buy the cheapest receiver on the block I'm getting all the power I need for my system to sing.

Was it good beer?

EDIT: Shoulda read the second page first.

I HAVE NO HONOR.

I actually DID have the top down today. It was glorious.

Sorry I was tardy, Chess. Had to pick up the mower and edger from service. I'm still really happy with that Honda mower even though it only puts out 80wpc.

I'm still happy with my Craftsman although it's quite heavy, which prevents me from mounting it 2-3' above my head.

Heh heh heh... imagining a lawnmower hanging over someone's head makes me laugh.

Honor restored!

BRRRRRRRRRRRRRRRR

crunk


AAAAAAAAUGH!



hee hee hee hee hee

particularly if it's a self propelled one...

Now THAT'S funny!

WPC?
Weeds Per Centimetre?

AlaskanAVGuy, this topic is clearly of high value, and I'm a let you finish, but this thread derail is one of the greatest of all TIME.

Tom, did I tell you about Gail's recipe for crock pot pulled pork, with the Coca Cola as the secret ingredient? It has to be regular Coke and not diet because, you know, cancer.

Have you tried this with Root Beer? Not bad either!
Regular not diet-
/Jeff

We just made pulled pork in the crock pot this past Sunday. My wife used cheap-o root beer. I told her, "Come on, at least use Barq's. Then we can have some caffeine in our meat."

Y'all great.

Wow...this just makes me shake my head....having been on this board for a long time, it never ceases to amaze me when someone insists on being "correct" above all else.

Kudos for those who kept calm and worked to get this across in a rational manner.

If anyone has a serious question on the subject, I'm sure it will be addresses. We've been over this subject many times on this forum, though.

No, no, no.... We have not covered anything like this before. Or at least, never read any of the posts/information:



Ok, I *may* have added something to the end of that inside the ( )...

reflect!

WPC

Not sure my financial adviser would recommend, but if it has enough power for decent headroom, sure. I'm not sold until BobKay gives his input though, that guy seems awesome.

You are partially correct you can listen to a Speaker at a moderate volume with only 1 Watt of power, however you need far more power for Theater like volume levels that we hope to achieve ourselves.
for example:

Axiom M60
SPL Anechoic 1w/1m(db): 87 dB

This means that with merely 1 Watt of power this speaker is able to achieve 87dB which is pretty decent. However most people like to listen a little louder. Like movie theaters who typically have a maximum SPL around 105dB. But I personally prefer a maximum SPL around 112dB which as you know every 6dB is a perceived Doubling in Sound to the human ear.

You have to double the input power to produce a 3 dB increase in sound output
(assuming the speaker is not reaching its limits).

Now to get more than 87dB from the M60 for example you will need an EXPONENTIAL amount of Power Output that FAR EXCEEDS a mere 1-Watt of power. Which is why a big Power Amp then becomes necessary to supply a huge amount of power as cleanly as possible without any distortion which may damage your speaker.

To get all the way up to what most Theaters are capable of at 105dB we would need about 128 Watts, and with my preferred listening volume of 112dB I would need an Amp that can output 512 Watts (See Link Below which uses a speaker with 85dB SPL). So as you can see you need an Amp with a lot of headroom to get your speakers to Full Potential. Keep in mind that All loudspeakers have a maximum power handling capability so keep this in mind when shopping for a Power Amp.

The only thing that wasn't discussed in this quick look was how when you add more than one speaker you get an Exponential growth in SPL. But without knowing how many speakers a particular person is using in their Home Theater I stuck to the basics with just one speaker.

"The key here is that in most or our home listening, there are small amounts of distortion caused by a lack of dynamic headroom. 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."



Sources: http://www.digikey.com/Web%20Export/Supp...df?redirected=1

http://www.axiomaudio.com/power

Axiom M60
SPL Anechoic 1w/1m(db): 87 dB
Maximum Amplifier Power capability: 250Watts

So now we can see that the M60 has a Max SPL around 111dB in a Anechoic Chamber
when supplied it's Maximum Power capability.

This is why it's important for new people to the A/V world to understand Tech Specs, that way you can make an actual comparison to various A/V products and get the most out of your hard earned money.

This Forum is for educating newbs and going over the Fundamentals with the veterans so we can have a valuable discussion about A/V equipment.

I think it is rude and presumptuous for you to assert what this forum is for.

Now, *maybe* you meant "this thread is intended...".

I also think your incessant use of the word "newbs" is pejorative.

Look, if you've actually gone through the 300,000 posts on the Axiom forum AND you've actually used the Search feature and you still feel like you have something valuable to add, please go ahead. To me, your posts seem to have the sole goal of demonstrating your superior intellect. It is off-putting. Most people know this stuff, or can find it either here or elsewhere.

I strongly suggest you start a blog.

Disagree.

Alaskan teacher,
you wrote "and with my preferred listening volume of 112dB".

i thought that each music recording had its own realistic playback level ("live" level), and the volume must be adjusted accordingly in order to give a good representation, as if you were at the concert.

if i were to adjust for a max. vol. of 112 dBSPL at the MLP for my music or movies, then it would not give me a very realistic reproduction on the great majority of those discs.
some would not be loud enough and some would be much too loud.

i have some CDs or movies that need a vol level of 6 dB over Ref. Level, and others that need as little as Ref. Level -20 dB.

"just the right loudness" has to be found by experimenting and you know when you've found it because the instruments you're hearing sound exactly like they were just a few feet in front of you, or on the side...
the representation then is so true that if you close your eyes, you will think the performer is right in front of you in the concert hall, not in your A/V room.
not in your A/V room, because the acoustic ambiance in the recording helps in making one believe that you're not in your living room anymore, but in the concert hall.

that's what Hi-Fidelity to the original is: transport you to the best seat in the concert hall.

final notes: 1: you don't have to teach here, to an empty class, it's a lot of time lost for you. you would be better to wait until someone asks a question to which you have the necessary knowledge to give a good answer.

2: your mindset does not synchronize well with the type of forum we have here. Like Tom just said above, start a blog; that would surely help people more.

Alaska:

I agree that you can never have enough power; however, my wallet is just so big, ha!

I have a Denon 7.2 AVR that is completely adequate to drive my modest 5.2 speaker setup at -10 Db with most movies in my medium size room (2400 cu ft). Higher than that, it is just too loud & for me, unrealistic - distortion or not.

One way that modern AVRs sneakily gain headroom is through the judicious setting of the Channel Xovers that relieves the AVR from having to produce the current for bass frequencies. That significant load is carried by the LFE Channel & consequently the Subs' Amps.

While most use 80 Hz, I set 60 Hz for my L & R (M22s) & VP160 CC. Works great in my system...

TAM

Alaskan,
someone recently told me that the amps in my system total
around 9.4-9.5 Horsepower.
how can that be, and such low numbers too?

i thought that power was expressed in Watts for audio and HP for cars-trucks.

hope you can enlighten me!

You are wrong,
When you Double the number of speakers - increase of +3 dB
this is what's considered to be Exponential Growth,
because it is also the same increase as Double amplifier wattage - increase of +3 dB so by adding an additional speaker qualifies as such an Exponential Growth.

Source for newbs: http://www.globalrph.com/master_speaker.htm

Great point as I too use a 60hz Crossover for my Front Soundstage.

Apparently your not aware of Receivers which tell you the dB off set by the input source.

For Example: When switching over to Directv on my Onkyo receiver it will tell me that
their is a 6dB off set for the source.

So to reach 112dB adjust volume accordingly. These are the BASICS.

Second I started this Thread and clearly have stated what Topics were to be discussed.
I'm not off topic in the least, perhaps you can visit the water cooler if you wish to discuss other Topics.

i never had a teacher in audio/video, but i thought (stupid me!) that an increase in dB was logarithmic; never heard of +3 dB to be "Exponential Growth". the two are immensely different.

this article might interest you Alaskan:
http://en.wikipedia.org/wiki/Exponential_growth
http://en.wikipedia.org/wiki/Decibel

Because a +3dB can be attained if you double your Amplifier Power this is Exponential Growth which is defined as:
Exponential growth occurs when the growth rate of the value of a mathematical function is proportional to the function's current value.

***(And because it's the same effect as Doubling the Amplifier Power it is Exponential Growth. Because you are essentially adding TWICE the power just by simply adding an additional speaker)***

And therefore my statement is Correct as is the rest of the Scientific FACTS that I have clearly linked to for people who are unaware of the FUNDAMENTALS.

This is exactly why I started this Forum Topic because even seasoned A/V people can forget the very Basics. Thanks for proving my point.

As it's apparent what my statement was implied to say, it seems that you are just trying to stir up a controversy for the way in which it was worded. In the future I shall adjust my literary comments to conform with your level of understanding, so I apologize if you didn't understand what was conveyed in my prior comments.


Source: http://www.globalrph.com/master_speaker.htm

I feel I must point out that you are wrong. The ear perceives loudness of sound, i.e. the acoustic energy transmitted by a sound pressure wave, in a logarithmic fashion, not an exponential one. (Yes, there is a difference.) The decibel scale is a logarithmic scale.

In case it's not clear, here are two charts for you. The first shows an exponential increase. The second shows a logarithmic increase.





Now that I have shown your understanding of a basic tenet of audio is flawed, how can any of us be sure the rest of your knowledge is sound?

THAT wasn't an answer to my post.
what i wrote is at the heart of good reproduction, and you said nothing about it, and what you wrote isn't very clear; i still don't know how to set the volume level for a recording so the max. SPL will be 112 dBSPL.

do you check the offset and then compensate with the vol. level and bingo! you have 112 dB max somewhere in the recording?

please enlighten me, teacher.
as a teacher, you should make certain that your writings are short, precise and clear so the "newbs" will understand.

imagine for an instant that you're listening to a piccolo and the vol. level has been set so the max. will be at 112 dB. Phew!

As I have already stated above you must have missed what I was referring to. Which is Exponential Growth of Power, as it takes TWICE as much POWER to have +3dB gain.

Use reading comprehension to try and understand the point I was making as you too are trying to manipulate the manner and meaning of what I intended to convey to the reader. I thought that this was clear but apparently some need help in understanding my meaning.

Why would I say that adding another speaker would Double the output...It will only add +3dB.

But nice graph i'm glad you used this although it is pointless because it takes about 10 Times as much POWER to Double sound.

Next

Source: http://www.globalrph.com/master_speaker.htm

there are many errors on that site's page; same for your writings, teacher.
because it's written somewhere doesn't mean it's right.

this will be my last post on this topic, my cat is barking at the monitor.

;-)

If you are using a Signal Generator with Pink Noise then you can dial this in pretty close to the preferred SPL level if your equipment allows.
However trying to dial in a CD or DVD is more difficult if you don't use a signal generator because of the constant change in dB.
I don't calibrate speakers this way because it's not efficient.

Also to your original concern I have already addressed how to adjust for different Source Levels by using your Receiver which will tell you how much dB you need to adjust to find the correct Level.

If your maxed and still cannot reach your goal of say 112dB then this is a problem of your A/V Equipment and are out of luck.

So can you please explain to us how and why you adjust your Max Level when using various CD's to make Adjustments??? I'm curious about your methods and knowledge of adjustments which don't make sense to me, please explain yourself.

I see so your saying that numerous websites with the same knowledge are incorrect according to you.

Please tell us all what is incorrect on these Websites as you claim to know of mistakes apparently. I would be interested if you would make a list. thanks

Sources i've referenced:
http://www.globalrph.com/master_speaker.htm

http://www.rayfes.com/caraudio/power.php

http://www.digikey.com/Web%20Export/Supp...df?redirected=1

i told you just a few posts up on this page how i set the volume control.

you should read before you answer. a glance won't do.

Ya I noticed this and then you asked the question again so I assumed that you had just glanced at my reply without reading it. I thought that you were going because of your cat....I guess your words are not literal. I'll keep that in mind when reading your responses.

So to the topics at hand:

1. You seem to know of a way to calibrate a System for specific SPL Volumes using various Music Sources...please share your explanation as I use a Signal Generator and Spl Meter.

2. You claim that their are mistakes made on the websites that I have been linking too. Please make a detailed list of all mistakes they made because you are more knowledgeable than the Sources I listed so you have claimed.

I'll be awaiting your Explanations Thanks for adding to the knowledge and understanding of A/V buddy.

usually the protocol for this type of thing is to answer questions when they come up by others.

all you are doing is googling keywords and parroting other web resources.

can you level with us? what is your actual background or credentials?

I'm sorry I didn't realize I needed any credentials to have an open discussion here.

Do you have anything to add to the Topic at hand?

I'm trying to stay away from all the gossip and focus on just the A/V side of things instead of making it personal. So excuse me if I don't answer your question to lead away from the subject matter, which isn't about me it's about the information and discussion there of.

Your welcome to give us your credentials if you wish thou....feel free to cast the first stone if you like, but I'm not going to follow that distraction anymore.

You don't need credentials.

You need to be pleasant.

So none?

I see that my information must be correct then because you have switched from trying to misrepresent the info to insulting myself. Let he without sin cast the first stone.

However i'm here to discuss the Topic at hand your welcome to join in.

Also, it would be nice if you learned the difference between your -- as in "Your speakers are very accurate." -- and you're -- as in "I don't believe you're right about that." This is grade school stuff, and getting it right would really help us take you seriously.

Well, that and an improved personality.

I want to know what your teaching background is? Your sig.

It was JB on post #402848 who started calling me teacher so I
gladly accepted the title which he gave to me.

Funny is it not....uh oh should I have said isn't?

Anymore distractions that you have for us???
Or are you just trying to bully this forum further off topic...

You don't seem to understand exponents. Multiplying something by two -- i.e. doubling -- results in linear growth. Multiplying by 10 also results in linear growth. Exponential growth requires ... drumroll, please ... exponents!

An exponent is the x in the mathematical expression "2 to the x power," which translates to "2 multiplied by itself x times." The larger x is, the faster the value accelerates upward.

Great post you sure work hard to find fault where their is none as already explained above....this has already been discussed.

Next

I guess the point I would make is anyone can do what you are doing. Any newcomer to the hobby can find out the very basics that you are presenting with google.

Experience is worth something, whatever it is.

What experience do you bring to the table? What is your background? A hobbyist? Industry? Installer? Sales?

Why cant you act as an equal?

Can you link me to posts where you have already talked about this subject and explained it? As I have stated at the beginning of this Forum that I started. I'm here to discuss Tech Specs on A/V Equipment for newbs and veterans alike. Because talking about the Fundamentals is a valuable thing.

Just like when I was younger I played basketball in college and even in college we still practiced our Fundamentals.

If this topic is too simple for you then you dont have to waste your time by bullying those of us that like discussing this.

This is not a sport. Just because we're on your court doesn't mean you need to practice your pick-and-roll on us. You didn't start this forum. You started a thread on this forum. The forum is a collection threads, topics, and individuals. We, the individuals, give respect where it is deserved. Thus far your behavior has demonstrated that you are not worthy of our respect. This is why we hound you, don't let your mistakes (grammatical and technical) slip, and why we poke fun at you in the Water Cooler section. You are a source of entertainment, but we will grow tired of you.

You dismiss my attempts at correcting your obvious misunderstanding of certain mathematical concepts. I have not trotted out any credentials to show you that I speak from experience -- I shouldn't need to. You can check if I'm right or wrong and perhaps learn something in the process. Refusing to even consider you could be wrong is a sure sign of a stunted intellect.

You might be a cool guy who's relatively new to the "social media" thing and don't know how to get along with people in digital space. You have nothing to prove here. We don't want you to prove anything. If this is an act, you can stop. If it's not an act, is it a cry for help? For attention? You confuse me.

I see so I should shut up because you don't like to discuss A/V Fundamentals and I started this Thread for this very purpose. Once again you troll & bully your way around this thread and have yet to add anything meaningful to the conversation. I already understand everything you have posted. Your not teaching me anything new here. Just wasting space rehashing old topics...how about I follow you around and make snide remarks at everything you post? Would you be as polite as I have been. Putting aside personal differences.

Well i'm too mature and have to much respect to Troll you, you have no honor. And so your remarks have no effect on me at all. If you want to bring up a discussion about something on topic then maybe we can learn something useful about Tech Specs that's relevant, as i've never once claimed that I know everything. I came here to bring up this Topic in the hopes that I might actually learn something useful that i've overlooked or been ignorant of. If you can have an intelligent discussion without making everything you post personal and passive aggressive i'd love to talk with you. However if you want to blog about your personal problems go start one.

If you want and an apology then fine I Apologize for the way I discuss A/V equipment. Now back to the Topic at hand lets all grow up and act like mature men here. My children know better than to bully their peers and if they did I would explain to them that it's wrong. Just because someone's different than them. Which seems to me, to be your problem with me, which is that i'm very technical and love talking about A/V Equipment instead of how I feel about my setup. I use measurements not metaphors. Except in the case of the basketball analogy where I was trying to make a discussion that you could relate too. Which was that Fundamentals are key and never beneath discussion and practice such as anything you do in life.

AVGuy,
If you're willing...

I am curious to know, when measuring from the MLP 11' away, at what SPL do I run out of headroom/amp?
In my 7.1 screen room I have 3 V3 M80HP's with V4 tweeters. They are powered by an axiom amp, the ADA1000-4.
I don't plan on listening at the level you confirm but thought it would be neat to confirm its a non issue at the moment.
That said my sound proofing efforts really paid off. If I had confirmation I could increase the SPL while I was out of the room and confirm I had an appropriate amount of head room I probably would try it out.
I am not a math guy, this is a legit question. If you need more info just ask.
I need an excuse to buy a ADA1500-4. Please help.

anyone has ever seen "Father knows best", a 50s TV series?
i've seen a couple of episodes when i was a kid,
and it's starting all over again...

behave now, children...
daddy will be back!
if you're not nice, he will "correct" you. (The Shining)

(could not help it! lol)

Just don't forget, guys, you're wrong.

And I'll damn we'll post whatever I want within the forum rules in any damned thread I want.

I'm still pretty sure that this dude is one of our old buddies back under a different name. He knows all the buttons.

Ken.C,
he's listed under the same username in AVS and many others.

Oh fine. ;-)

on April 7th. last i sent the "teacher" this PM to which i still have no answer and see no change in behavior even after 5 days:

"i would like to suggest the idea that diplomacy can go a very long way.

have a good day! :-)"

How pathetic. It's time for YOU to be taught some BASICS my pompous new acquaintance. Your shallow apology isn't close to genuine in my view.

My experience here and the reason I visit daily is because in general people are respectful, kind, and informative. Regardless of the wealth of knowledge you claim to grace us with (some of which is incorrect), your approach is UNACCEPTABLE despite numerous attempts by others to enlighten you. You apparently are inexperienced as to how to treat others on the net. In this sense you are the NEWB.

YOU'RE acting more like a bully and troll here. I don't want to hear about staying on topic pal. You're no moderator, just some guy who started a thread. You're ATTITUDE has overshadowed the topic. My suggestion is to take others advice and start a blog elsewhere and see how you do.

If you stay much longer, find a way to ERASE your condescending tone.

You WILL NOT continue in this way and not be called out by me and others.

DO NOT PM me. It will become public.

It is YOUR maturity level that must reach ours. You are OUR student in this regard. It's been a while since someone like you has come along. Let us see if you improve.

Next.

Well, that says it all...

TAM

I'd still be curious to know a semi official answer.
To remove a few of the variables, please consider 2.0 or 3.0 with the M80HP's only.
I'm fairly certain the 1000 and HP's are a perfect match in this room. I know I have quite bit of head room but the movies I watch will chew through that fairly quickly in the instantaneous peeks.

Guys, just ignore the Alaskan a$$. He believes is like Khan a superior intellect and we all should bow to him. Don't feed him and he will go away. I for one will avoid this forum for a while as I am tired of this nonsense.

Anyone of you children would like to review their Alphabet Basics with me ?
- Remember! we start with the letter A...then B...then it's letter D...
- ...and, we finish with the 4 letter word.

Not sure if that was directed at me but...
I noticed I had an issue sometime around ohms law. Up till then I did just fine, then equations started looking like alien giberish.
Its a shame really. I know it should be easy.I think it might be dyslexia related. Seems to be the only time its an issue.

Hey brwsaw,

Someone check my math!

You can use an online calculator to find where your speakers will theoretically top out with spl within the rated output of your amp. Then add 3 db for every doubling of speakers playing simultaneosly.

Ie. 1 speaker 110db
2 speaker 113db
4 speaker 116db

Then you must subtract from this the decible drop from source distance. For this, each distance doubling drops 6db.


So if 1m is 110db
2m is 104db
4m is 98db. Etc.

Axiom specs the m80 in room at 92db@1w/1m. At 4m they should be around 80db.

So take 80@1w
83@2w
86@4w
89@8w
92@16w
95@32w
98@64w
101@128w
104@256w

Add 3db for a stereo pair.

All these numbers are purely theoretical. They depend on the listening axis, acoustic damping of the space, and listening material. We are also more sensitive to certain frequencies.

The best way for you to be happy is to listen to your source material in your space and ask how much more power does it really take to get to that next step? Probably lots according to the formulas.

Really, the only way to check this in a meaningful way is to play your reference material and measure peak and average levels with an spl meter. Buying a huge amp will add headroom and can make listening a more engaging and dynamic experience. The purpose is not to increase nominal listening levels, as your amp is likely already capable.

Nominal listening levels are nowhere near the 110db mentioned earlier. That dba is dangerous to hearing at sustained levels.

That's pretty interesting. By that model the 1000 is perfect for this room. I was pretty sure it was. Thanks.
FWIW I watched the first 2 episodes of Band of Brothers in 3.0 and episodes 3 and 4 in 5.0 last night and at no time did the towers seem strained. I'm pretty impressed by how well they handle extreme jumps in SPL while remaining clear and detailed.
I still need to work on the room but these towers were everything I was hoping they would be.
The second amp may still happen but only if I upgrade from my RX-A1010 to a dedicated 9 or 11 channel pre/pro.