Acoustic treatment for my living room - Page 12

No, it sounds like overwhelming defeat for people telling you to stare at sonar charts of reflections .

Or this:

"So when audible effects due to side-wall reflections exist, they range from negligible to positive, depending on the nature of the program material."


Everything is an option. You can put the speaker under a pile of dirt and listen to it and no one would come and fine you . If you are asking Dr. Toole which way to go, he will tell you that the preference is to leave the sides reflective. It is a recommendation backed by pages and pages of justification. He is very strong-willed there and no amount of reading the tea leaves will let you get clarity otherwise.

If you want to kill those reflections, by all means do so. Remember, both he and I are trying to free you from thinking that you must because some ETC graph told you. Or your gut. Don't do it for those reasons. Neither is backed by the data we have. Do it because you know the difference and prefer it that way.

So you are not about high fidelity, am I right? It's certainly not what you care and sell. It's all about personal preference. That would be considered no fidelity.

I don't understand. Our interior spaces have varying levels of furnishings which create varying levels of reflection, absorption, and diffusion. This is our natural setting.

You can measure these things and change them to meet certain measurements, but since that is not our natural interior space, shouldn't changes made be to something more preferable? After all, there is no standard room environment that is "correct," is there? If not, then what do we have but preference?

what on earth would put you up to recommending an anechoic chamber as some sort of "idealized" acoustical space?



who are you talking to ?


didnt i just call you out on making an attempt to speak for yourself and not others??? "you all"? just who are you referencing here?




why couldn't you find any of MY commentary to quote here?
why would you reply to MY statements with quotes from arny and ethan? quote ME if you're going to respond to MY commentary.




well what do you know --- another example quote that certainly is not by myself. why do you keep quoting other users? quote ME if you are going to respond to MY commentary.



we get it - you operate under the impression that you speak for toole - the rest of your audience can see right through your commentary.


preserved for ignorance.


commentary preserved -



commentary preserved -


commentary preserved -



commentary preserved -

^^that is what amir says that toole says --- because as you already know, amir speaks for toole. but let's see what toole actually says:

what tool are you using to make such measurements ?

He says more than that. You keep quoting that line that you took from a forum and ignore that it came from a full paragraph. This is the full context:

"The real solution, for professionals as well as consumers, is loudspeakers that deliver similarly good timbral accuracy in the direct, early reflected and reverberant sound fields. This can be described as a loudspeaker with a flattish, smooth, axial frequency response, with constant directivity (which together result in flattish, smooth, sound power). Then it becomes an option, whether the room is acoustically damped, or not. If reflected sounds are absorbed, the listener is placed in a predominantly direct sound field, making the experience more intimate, and the imaging tighter and more precise. If the reflections are allowed to add their complexity, the overall illusion is altogether more spacious and open, to many listeners, more realistic. In part, this is a matter of taste. In either case, a room-friendly loudspeaker will yield timbral accuracy. So, at middle and high frequencies, the proper solution to getting good sound quality, is to choose good loudspeakers to begin with."

That was what he said in 1999. This is what he says in his 2008 Book, Sound Reproduction, Loudspeakers and Rooms:

"The matter of side-wall reflections of L, C, and R loudspeakers warrants some discussion because of the widespread belief that these reflections should be eliminated as a matter of ritual. The ritual had its origins in recording control rooms—listening in stereo—encouraged by alarmist cautions about comb filtering (see Chapter 9) or degraded speech intelligibility (see Chapter 10) or masking of other reflections within recordings (Olive and Toole, 1989). When examined, none of these turn out to be problems.
[...]
So what does one do with them in a home listening room? If the loudspeakers have good off-axis performance, and especially if the customer likes to listen to stereo music, my recommendation is to leave some blank wall at the locations of the first lateral reflections from the front loudspeakers. An area with a small dimension of at least 4 feet (1.2 m) centered on the refl ection path is sufficient. Figure 16.6 shows reflected pathways for one room. Providing reflections for the front rows is probably sufficient."

And it is not just him that says this. If you ever have the privilege of hearing Allan Devantier, he will tell you the same thing.

Anyway, we have been around this block twenty times. I want to make sure the message is not lost: no one is going to chew you out for putting panels on the walls. The point is the opposite: don't let people bully you into throwing money here just because they think you should. Buy Dr. Toole's book, or better yet, attend his in person class. Then do with it as you like with the knowledge. Having done that, I can tel you with 100% confidence that little of what Localhosts says resembles his teachings.

and the very next sentence:

REW is the only tool I have. I'm here trying to learn something. I've read Toole's book and found it interesting, offering a point of view I hadn't seen on most forums (first reflections and all). It's a mess to see such staunch advocacy for one position or another in an area that generally comes down to preference.

REW is not a tool. it's a measurement suite but it in itself is not an individual measuring tool. what tool were you referring to in your previous post?

the only one with any "staunch advocacy" in this thread is amirm. who else is recommending one and only one position with respect as to what the OP should do?

Look up the meaning of "high fidelity" and understand what it means in sound reproduction.

I understand what you were saying. The room affects fidelity. There is no standard for how that room should be configured. When one measures, all one gets are measurements. Measurements need to be interpreted and correlated with user preferences in order to mean anything when it comes to listening. Much of Toole's work is about preferences. One may not agree with his methodology or conclusions, but he's out there with his well informed opinions. Your statement made it seem as though preference doesn't matter, but without astandard reference for room acoustics, preference is what it's about.

I've been reading these room acoustics threads for awhile, and I see very little clear agreement on what should be done in a given room. It just seems like a lot of opposition with little advice or real world examples.

I wasn't referring to a tool. I was trying to make the point that listening spaces should be set up to user preference. That's all. I'm reading this and other threads to try to learn how a listener should go about analyzing the room and the potential effects of any steps taken to improve fidelity. I'm not looking to debate. I just want to understand goals for room design.

What is your position on what the OP should do?

What made you think we are without a standard reference? Not to mention your use of the word "reference" in that sentence. Don't you understand what referencing is? The source to reference to is what standard is. Every reproduced sound has a reference.

I take the point that it is not *your* job to find *my*data, However, you at least seem to know what is there, I don't. So it is easier for someone who knows what they are looking for than someone who does not. But, as I said, point taken.

Listener sensitivity...to WHAT? It cannot be to 'the effects of stereo' when listening to mono can it. For sure, mono is fine for timbre and balance yada yada. Mono is not fine for stereo.

Howabout the test is for Comparison of Loudspeaker-Room
Equalization Preference for Multichannel,
Stereo, and Mono Reproductions, I don't see any test there for the effects of treatment in stereo.

At least I can run stereo in mono and whilst it might not be exact, I am reasonably certain it is closer to mono than mono is to stereo.




No, you missed my point entirely. That is, an FR sweep does not give any information about time. From that sweep there is no way you can tell from inpsection that one speaker is closer by a foot than the other. Of course it is simple set up, and you would have to do it. Because time IS important.

One of *your* planks is that eq fixes time, fix the graph with eq and you can forget all about time. Ok, I completely accept you know where that applies and does not, but you continually reduce it to the simple and wrong maxim of 'eq everything it will be ok'.

Even in the bass which is where I think you really mean, I have showed you a few times now that does not always hold true. I can't be bothered posting the graphs again as you'd probably ignore it once more.

Suffice to say if the subs are half a second behind the mains, no amount of eq (or how pretty the graph is) will fix it.

See below


Just a quick one on the right speakers and your assertion that out of the bass the speaker dominates (cause the graph does not vary as much up there, proving the room can be 'ignored')..what happened to the accurate speaker?



Above the transition freq the speaker does not look very accurate compared to it's 'real' measurements. Well not that true, +- 5db or so is not bad in room I'll grant, the point is that you can hardly make the claim that 'the speaker literaly sets the tone', the room clearly has influenced the response you hear.

Just btb.



You know what? Listening in mon, well I can readily accept that ANYTHING which increases LEV will be deemed desirable or beneficial.

Why? Cause it is in mono. No appreciable soundstage, width nor listener envelopment. Which by the research shown is exactly what listeners crave.

It is little wonder then that as it increases listener envelopment listeners were willing to add reflections having sound levels and delays that would cause strong image shift and broadening

The question is, in stereo (that can have lots of LEV that mono cannot) would listeners be willing to have 'strong image shifts'? Again, there would at least be a strong subset that most definitely would not, to them imaging is everything. One of the dreaded effects in stereo is the two foot mouth



I don't dismiss it at all, just question it's usefulness in judging stereo. Fine for timbre et al. The danger is that it can lead to erronous conclusions! (the only test in stereo you have mentioned involved 'heavy drapes' which I think would run counter to your own requirement that treatment be broadband if done)

However, I will admit a few things here haha. It has got me thinking today as I was bored mowing a few acres...there are a lot of 'accepted wisdoms' in audio...I too just accepted the wisdom of treatment. Don't get me wrong, I use it andit worked wonders, but as I said I was treating a different thing, slap echo as it turned out.

But also I don't think there are any sacred cows...and have been wondering how to do a controlled blind test on the 'general' preference on treatments in a normal listening room norally furnished (the other thing my experience does not cover...my room is not normal)

It would involve a bit of work (the challenge of which is appealing) but then again come oct I'd have about thrity guinea pigs which should proved a decent enough number.

I might ponder it a bit, but have been wondering what project I could take on to keep me occupied and today this popped into my head. Could even document it via video..

Ethan, coming back to a 'challenge/question' from amir....is there a reason you have not done blind tests? Does it pique your curiosity as it has mine? It is probably one of those things, we never think to question what we believe so it likely never occurs to us.

If *we* went ahead and give it a shot, would you guys be willing to work with us to nail it down as best we could prior? Things like what to test, how to gather the responses... things like that.

Anyway some ramblings just now.

EDIT though I should add, it will be tested in stereo natch!

I understand what referencing is. Is there a standard desired reference acoustic space against which to compare our rooms? One that will provide the most accurate, natural, and pleasing reproduction of all sources.

Should our listening spaces should have the same targets as a mixing studio since that's where the reference was created? Are there standards applied across all mixing and mastering environments used for the creation of music and movies?

My simple question is what should we be aiming for in the acoustic properties of our listening space regardless of the source. Is there something standard, where perfection can be measured or are there different approaches taken based on preferences for correction?

Harman's research is predicated on an acoustic space defined in IEC 268-13 (1985). In order to achieve a similar acoustic space, you may need to use acoustical absorption and diffusion panels depending on the configuration of your room and the acoustical properties of its furnishings. Good luck!


Harman's IEC 268-13 (1985) Room

and as stated many many times - a user does indeed have a choice whether they would like an accurate, critical listening space or a subjective pleasing listening space based on their own personal preferences or based on the research of what others "prefer".

no one is denying that.

nor is anyone insisting that a user MUST adhere to a critically accurate listening space - as they might feel such an environment is not personally pleasing to them. that is for them to decide. however, if you are interested in maintaining accuracy of the direct signal with respect to localization, imaging, and intelligibility, it certainly doesn't hurt to see what the "studio guys" are doing as those are the environments where accuracy is of the utmost importance. and those particular acoustic models have been around for decades...


yes - the user needs an "end-state destination" before receiving advice on the directions to take to "get there".

and im confused by your commentary insisting there are "no standards"

Would you mind providing a reference for that?

Here's one:

http://www.aes.org/tmpFiles/elib/20120416/13686.pdf

Here's another:

http://www.aes.org/tmpFiles/elib/20120416/5270.pdf

The room they built at the Canandian National Research Council facility, where most of their research was conducted, was an IEC 268-13 (1985) room.

To be honest, I've grown weary of discussing the subject with you. It's like trying to have a rational discussion about religion with a recently converted fundamentalist evangelical preacher.

The test talks about validity of testing one speaker versus many. I thought that was what we were discussing. It showed that in general we are less sensitive to artifacts with more channels than less as the scores of the control/reference went up just because there were more channels. This narrows the gap between different test samples even though no quality improvements were made. Yes, it did not fully address your point but did demonstrate the core aspect of "why mono."

BTW, did you see that I did find the specifics related to stereo testing? Here it is again:
""It was in this room that experience was gained in understanding the role of first refl ections from the side walls. The drapes were on tracks, permitting them to easily be brought forward toward the listening area so listeners could compare impressions with natural and attenuated lateral refl ections (see Figures 4.10a and 8.8). In stereo listening, the effect would be considered by most as being subtle, but to the extent that there was a preference in terms of sound and imaging quality, the votes favored having the side walls left in a reflective state. In mono listening, the voting defi nitely favored having the side walls reflective. See the discussions in Chapter 8, and Figures 8.1 and 8.2, which show that attenuating first refl ections seriously compromises the diffusivity of the sound fi eld and the sense of ASW/image broadening."



It is assumed in these discussions that you acoustically time align speakers. That is not under dispuate. If you put one speaker 10 feet back, it is not good . If you wanted that acknowledged, here we are .

The time aspect being argued about is analysis of the room response in time domain. There, the opposite of what you mention is in play, in that since you are only looking at amplitude of reflections and not what those reflections mean spectrally.


Absolutely not Terry. My "plank" was that time and frequency are interconnected. That is not at all the same as "EQ fixes time." EQ is a tool to fix frequency domain but it cannot fix important problems there. One is speaker directivity. If the direct and indirect sounds don't match, you can't fix that with something upstream of both of them. If you did apply EQ, both frequency and time response will change but not for the better (or necessarily so).


No I looked at it Terry. And I thought I addressed. I certainly have covered it in my article on subwoofer optimization using Sound Field Management. You can indeed use timing (phase) of one sub vs another to get lower seat to seat variation and smoother response.

Again, I think you misunderstand the nature of the disagreement. The dispute seems to be above the modal region and whether ETC is a good tool for that. Dr. Toole disagrees and does not use it. Your graphs were in the modal region where there has not been an argument for using ETC there.

BTW, JBL Synthesis Sound Field Management is a form of an "EQ." It both shapes the response of the subs and changes their timing and level to best optimize performance of multiple subs. The use of EQ in this regard though is not the classic use that I was referencing however.


Again, if you read my article you see that I did not try to use EQ at the first stage. Indeed, I made a point of it: http://www.madronadigital.com/Librar...imization.html

"It is important to note that we left electronic EQ to the last step, not first. It was critical to deploy multiple subwoofers and SFM to smooth out the frequency response across all the seats. "

SFM is performing the optimization you did manually although it is not a "time analysis." It is an iterative process attempting to find the optimal solution for three variables in reasonable amount of time. Its analysis is actually in frequency domain, attempting to get the smoothest response across all the listeners.


I will be covering what makes for an accurate speaker in the next article where I talk about response above transition frequencies. That graph is not meant to show what an accurate speaker does.


Actually, the "real" measurements are not there. To determine the reason for the dip, you need to have the 70 point measurement that shows how the response varies off-axis. I will include these in my next article discussing response above transition.


Well, to the extent you don't listen to a speaker in an anechoic chamber, the room does have an effect. The point of he article was whether you want to fix the 23 dB variation in the bass or something else. I would say start with the 23 db bass. For above transition, you can buy speakers that do very well and influence heavily what you hear in your room. Not so in bass frequencies.


At some point we have to agree or disagree with what I will call theory of integration for the sake of the discussion. Would you agree that if I took one of your speakers and replaced it with a plastic computer speaker that you will hear a drastic difference in fidelity? And that I can hear that better if you turn off the big speaker that I did not change? It is important to see the performance of individual items even if your application does involve using multiple.


Actually, Dr. Toole makes the case that reflections in a room are never enough to increase envelopment. He says that has to be in the recording as our rooms simply are not large enough. This is why he also likes multi-channel:

"As we adjust our focus to concentrate on sound reproduction in small rooms, it will be seen that various interpretations of ASW, image broadening, will be contributed by the room itself, but the sound levels and delays required for LEV[Listener Envelopment], envelopment, must be delivered through multichannel audio systems."


If LEV is in the recording as it must due to above, then it is going to dwarf "image shifts" that may be due to reflections in the room. One is distinct and strongly placed, and the other not. Again recall that LEV cannot happen in small home listening rooms due to reflections as it requires delays > 80 msec.


Those curtains were broadband. And it is not my requirement but Dr. Toole's.

You post a picture of Harman's reference room. Neither paper above covers that. Here is the AES paper on that:

Title: A New Reference Listening Room For Consumer, Professional and Automotive Audio Research

I did a search on IEC and did not see any reference to it in that article.

On the NRC rooms, there are references to it but not in your favor :

"The AES and IEC standards were intended for monophonic and stereophonic testing of loudspeakers in typical domestic listening rooms. Both these standards are now quite old and the recommended room sizes are too small to allow multiple comparison of multichannel systems.
[...]
The MLL's [his room] volume exceeds the IEC and AES recommended limits of 110 m 3 and 120 m 3 respectively because the standards were intended for small domestic stereo listening rooms."

Yes, they draw on some research they have performed in IEC style rooms. But in no way your implication is right that one must have an IEC room for their teachings to apply. Or that their recent room is based on that old standard.


Look, answering your argumentative and negative posts is not my idea of having fun either. You chase me from thread to thread with monocle focus on proving me wrong no matter what the topic or the position I am taking. Your goal is not to discuss the topic but to put the person in negative light. Your commentary above is prime example. I focus on the topic, you repeatedly focus on me. If your knowledge and data are strong, let them speak for themselves.

And show that you hold a consistent idea regarding audio no matter who you have to side with. Don't drag your feet when I ask you if double blind tests are good in acoustics just because it is me who says that should be the case.

Knowing that drapes are not a solution for fully attenuating reflections down to 250-300Hz range, one would surmise that these reflections would be "colored/eq'd" similar to what local and dragonfyr have been stating. What might have been the outcome of the listener's preference if only the high gain reflections were fully attenuated and not colored?

exactly! he copy-pastes all of his commentary (many times out of context) - and presents it as FACT to support his viewpoint (read: business model). and if you want to contest it, he conveniently side-steps and simply tells you to "take it up with toole" --- which takes the burden off of him...

how convenient it must be!

tantamount to someone copy-pasting something from the bible to present as FACT to support your viewpoint , and then if someone else calls out a contradiction, he simply tells them to "take it up with god".

how many times in this thread has his response been to "take it up with toole".

i can't wait for this to be presented. can we expect further misunderstandings of basic acoustics as are present in your LF article? eg, the complete misunderstanding of simple superposition vs that of a room mode?


those curtains are NOT sufficient to fully attenuate an indirect specular reflection due to the lower schroeder cut-off frequency.

oh look, another "don't blame me im just the toole messenger" response -

LOL, beautiful.

--Ethan

The notion that the effectiveness at all of acoustic treatment needs to be proven by blind tests as proposed by Amir is preposterous. Of all the things people can do to improve their system, adding acoustic treatment is as far from a subtle difference as it gets.

Now, if you're talking about blind tests to assess this type of treatment versus that type, that's something else. No, I haven't done blind tests, and I haven't even "tested" anyone other than myself and interested friends. But I've done a ton of listening and comparing, and again, the differences are so obvious that blind tests are not needed. Tell me if treated versus untreated is not blatantly obvious in this video:

Hearing is Believing

Where blind tests shine is proving to "cable believers" (as just one example) that all wires sound the same unless defective.

If this is not what you're asking, please clarify.

--Ethan

Let's be clear. They are not "saying" it. They are repeating Dr. Toole's teachings. In that regard, don't you think it would be strange for Dr. Toole to not be following his own understanding of the topic?

To wit, here is the larger quote on that point:

"Bringing in the rest of the furniture and some drapes finished the task. The drapes were chosen to be acoustically effective: heavy cotton with lining, pleated to less than one-half fabric length, and hung 4 in. (100 mm) from the wall so they would function at lower frequencies. The room sounded utterly normal; conversation was very comfortable, and reproduced sound, then in stereo, was excellent.

It was in this room that experience was gained in understanding the role of first reflections from the side walls. The drapes were on tracks, permitting them to easily be brought forward toward the listening area so listeners could compare impressions with natural and attenuated lateral refl ections (see Figures 4.10a and 8.8). In stereo listening, the effect would be considered by most as being subtle, but to the extent that there was a preference in terms of sound and imaging quality, the votes favored having the side walls left in a reflective state."

It is a fallacy to think purpose built absorbers are not going to color your sound anyway. It is not like they have ruler flat response. Here are some data from Ethan's web site:




Here is something to chew on . From Dr. Toole's Cedia course:

"When asked for their opinions in double-blind tests, listeners generally
preferred the sound from wide-dispersion loudspeakers that were wellbehaved
off axis, and that had the benefit of reflecting side walls. The only
listeners who expressed a dislike for reflective side walls were audio
professionals, when they are mixing recordings (generally in stereo).

Even some recording engineers, at home at home and at work, preferred
lateral reflections. So this is not a totally black and white issue. It depends
on the listener, what that listener expects to hear, and it depends on the
recording - some recordings clearly benefit from lateral reflections, in others
it makes little difference."

It is interesting to see how hard it is for you all to give up this notion of reflections = bad. It is amazing that Dr. Toole's teachings go back nearly two decade on this front, yet it seems for many to be hearing it for the first time. The forum chatter/noise is so much louder as to overwhelm expert opinions otherwise.

So again, do as you like. But don't be afraid of not treating side walls. Buy well behaving speakers that use that to their advantage to give you a more pleasing listening environment.

I showed, and you agreed, that acoustic material can color the sound of a speaker. If that is the case, you have some theory as to why that change is always for the positive?


Why not? You disagree with these findings on sighted vs blind tests of speakers showing different results? http://www.avsforum.com/avs-vb/showt...4#post21898894


No one is arguing that there is not a difference. But when there is, we still want to quantify it without bias. You seem to think bias cannot enter this area and that is not backed by research.


No, blind tests are important all the time. Your brain doesn't park placebo just because it is hearing acoustic products vs cables.

yes - it is quite strange.


am i reading this correctly? how much surface area did the drapes cover for this test? why would you coat such large surface areas with absorption? instead, for such a test, it would have been better to SURGICALLY attenuate ONLY the high-gain indirect reflections and not merely and BLINDLY cover the entire surface.


those are LF absorbers for the modal region - NOT broadband porous absorbers for the specular region.

notice how it says "in corner" --- tell me, why would you place specular absorbers in a corner? why would anyone care what the absorption properties are in the specular region of a LF absorber designed for the modal region? hell, we usually COVER the Lf absorbers with a REFLECTIVE membrane such that they reflect some specular energy BACK into the room and to LIMIT the amount of specular absorption within the room! and for the LAST time, absorbers do NOT have a "frequency response".



clueless - he STILL lumps all reflections together! there is NO getting through to this guy.

tell me, amir - are the first order sidewall reflections in Blackbird Studio C the same type of sidewall reflections in my living room?


lol - much of which was already understood well before toole began his career.