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Side Wall, Floor and Ceiling Reflections - Page 2

post #31 of 135
Quote:
Originally Posted by amirm View Post

The relative importance for ALL reflections pales in comparison to optimizing the low frequencies. If you want priority, that is where you want to focus.

That may be true, however the question at hand is reflections (which are still important) so hopefully we could stick to that topic only here smile.gif
post #32 of 135
Quote:
Originally Posted by diomania View Post

You brought it onto yourself with your intentional deflection, redirection, complaints and making things up as you go (a k a dance).
As a person who practices their style, I am not surprised that you sanction what they do. As I mention, I am perfectly cool with it. Let them insult me. I don't become stupid just because they declare me so. Your point is wrong anyway as I don't think these people deserved the insults:

Here is a response to poor Bigus:
Quote:
Originally Posted by dragonfyr View Post

Yeah, and it is available where? Look bigus toolus, the qualification regarding both minimum phase systems was mentioned how many times? And the relationship of modes to minimum phase as well as to modes specifically was mentioned how many times? I'm tired of ms. congeniality constantly following me around like one other lost puppy dog some may know and trying to make points that simply do not exist had someone actually bothered to read the entire post for meaning. I am tired of this. I hope he explains the remaining issues regarding the ETC and its use regarding issues involving specular reflections, for which Audyssey and similar 'room correction'(sic) devices simply cannot - despite spurious assertions of systems that can overcome fundamental limitations of physics...
Then this one later:
Quote:
Originally Posted by dragonfyr View Post

blah blah blah. More social commentary from one who has yet to offer any contribution to the subject of acoustics. Yet you CONTINUE to falsely accuse me of calling people here "idiots", when my reference was clearly to how the marketeers of OmniMic conceive of their intended market! And I OBJECTED to that characterization! But just as with acoustics, don't let facts confuse you! ...But just keep repeating the Big Lie as you posture as Mr. Congeniality. What would be a radical change would be if you spent just one fraction of the time you spend sanctimoniously criticizing others delivery and actually attempted to pursue some of the information that has been presented that you claim to want so badly. JUST ONCE.

To our own sdurani in this thread:
Quote:
Originally Posted by localhost127 View Post

you can dance around the topic all you want. you are simply incapable of answering even relatively simple questions with regards to acoustics.....what does that even mean?
so - you are not able to provide any polar responses? ...i thought so. more vauge commentary with little to no substance.
Did you say "dance?" Here he is:
Quote:
Originally Posted by localhost127 View Post

dance dance dance - you completely ignore the effect that the boundary's acoustical impedance has on the spectral content of the reflection (until brought to your attention) - and i have yet to see you promote or recognize in any of your commentary the significance of the boundary on preserving such spectral information. and now, you continue with such vague commentary such as "it doesn't look too different" .... "similar" ... etc. and you've yet to present any responses to my questions regarding the ideal early arriving energy...
And more....
Quote:
Originally Posted by localhost127 View Post

reading comprehension 101. keep dancing. looks like it is not possible to extract any more information from you regarding the questions that have been proposed...

To another poor soul, alittletank:
Quote:
Originally Posted by dragonfyr View Post


Yawn...Local, why bother? You have folks here whose primary reason is not to learn the actual acoustical physics - as we are told repeatedly that such is far to difficult for the average Joe, who can't be bothered to read 76 pages of Sound System Engineering. Instead their purpose is validation. They have had much fun reading copious marketing brochures full of miraculous promises, or copying something they saw elsewhere (regardless of the actual purposes that may have been designed to remediate - but hey, it looked cool!), or repeating what someone else did based upon their 'interpretation' of what someone else did based upon their reading of what someone did on another Internet site - actual behavior be damned. And regardless of how objectively valid the actual behavior, since the result is "different" from that which they started, it is necessarily defined as "better". What could be simpler - or more enjoyable.

So why try to upset their world of enjoyment based upon a myopic ignore-ance of the larger world of acoustics. Just because you have taken some time to actually read and learn from primary sources and current models and research, why do you persist in upsetting he good folks who have some Luddite notion that one cannot find enjoyment in identifying ACTUAL behavior, noting ACTUAL problems, and surgically using the appropriate treatment to effectively treat, and verifying the effectiveness of such treatment in order to achieve a coherent acoustical response model that is appropriate to their intended use?

You see, the real problem is that in the absence of such awareness, and the refusal of folks to make an attempt that is commensurate with the stated importance of the response of their room, all you are doing is reminding them that their oh so enjoyable efforts are in most cases less than optimal. And of course the cry is to burn the witch! And these folks have spent much more time assembling torches and pitchforks from some Internet page claiming to offer the latest greatest most effective torch and pitchfork design than they have actually trying to read some readily available texts on current models, tools, or acoustics pertinent to small acoustical space acoustical spaces.

And don't worry, there are plenty here with a commercial vested interest who will chastise you as well, as rather than advancing an understanding of actual current acoustical models and concepts, they have a vested interest in cultivating the cult of personality as they sell services marketed not on objective performance that translates to subjective experience, but they sell the 'image' and the enjoyment of casting their worries to the side as long as they only employ their services or buy their magical products guaranteed to solve everyones' problem - regardless of what they are - based on the foregone conclusion that if you have already justified spending that much money, OF COURSE you are going to hear the desired difference as you have already decided it is worth it - regardless of whether it actually exists or not!

If I am not mistaken, the last paragraph was a shot at Dennis Erskine. He fires back with this:
Quote:
Originally Posted by Dennis Erskine View Post

So, why is it you are so defensive about a statement you didn't make. Odd. What hit home? The fact that you want us to take you at face value with no objective proof you have the creds, experience, expertise and 20 years of playing with neat toys? It don't know what "legal standing" has to do with anything; but, it seems you just aimed that gun at your own foot. Where's your objective proof? And, btw, third party objective proof for that specific room does exist.

All of this and then some in one thread! And unlucky for your point of view, devoid of my participation wink.gif.
post #33 of 135
Quote:
Originally Posted by amirm View Post


Or did you sit in an anechoic chamber and simulate what happens when a reflection is there vs not?

If so, you are smarter than the rest of us combined..

We'll let the rest of the folks enjoy a laugh as they ponder the illogic of the completely absurd statement above...

Yup...sitting in an anechoic chamber analyzing reflections...

It is statements of substance like the above that lavishly illustrate the extent of one's acoustical knowledge when they dare to venture away from posting content limited to material consisting solely of parroted word searches and cut and paste exercises and attempt to speak extemporaneously.

And to add insult to injury, who is it making pronouncements about who is "smarter"? At least that is one question that has been summarily answered.
post #34 of 135
This will be the only warning about petty bickering before long-term bans are handed out...
post #35 of 135
Quote:
Originally Posted by dragonfyr View Post

We'll let the rest of the folks enjoy a laugh as they ponder the illogic of the completely absurd statement above...
Yup...sitting in an anechoic chamber analyzing reflections...
One of the most common methods to analyze the psyhcoacoustics of what we hear is absurd? The goal of such analysis is to isolate the effect of say, a single reflection. This is done by using two speakers. One as the primary speaker and the other, simulating the reflection. The latter speaker is put at the target location of the reflection to be analyzed. Then using electronics, the signal going to the primary speaker is also sent to the one acting as the reflector except that its level and delay is adjusted as desired to test for the desired effect. This was the nature of such testing which Dr. D'Antonio quoted in his presentation:

i-45H4Xpv-X2.png

Here is the setup that was used by Dr. Olive to generate the bottom two graphs there per my description:

i-QJKMz48-XL.png

From his AES Journal report:"The majority of the experiments were done with this listening configuration set up in anechoic chamber, but certain experiments, as noted, were set up in a normal room."

As you know, the journal papers go through peer review. So if there is some major lapse of protocol, that causes experts to laugh at the work, you would think it would have been caught.

Similar set up was used in the earlier report on reflections which was published in the Journal of Acoustic Society of America (ASA): Echo suppression in the horizontal and median sagittal planes: "The subjects were tested individually, in 3.0 m (wide), 4.3 m (long), 2.4 m (high) anechoic room (IAC #107840)."

As with AES Journal, ASA Journal papers are also peer reviewed.

Would you please educate us on what these researchers are doing wrong? And how they still managed to get their results published and quoted by respected researchers that you often reference, i.e. Dr. D'Antonio?
Quote:
It is statements of substance like the above that lavishly illustrate the extent of one's acoustical knowledge when they dare to venture away from posting content limited to material consisting solely of parroted word searches and cut and paste exercises and attempt to speak extemporaneously. And to add insult to injury, who is it making pronouncements about who is "smarter"? At least that is one question that has been summarily answered.
I don't think I described anything profound here to be a sign of being smart or stupid. Logic says if you want to analyze the effects of a single reflection across many levels and distances, then the above is a very effective and logical method. Logic also says that for consumers, testing these individual variables is very difficult. Hence the reason we draw on research such as ones mentioned. But again, happy to be educated.
post #36 of 135
Just occasionally words have meaning. It even happens in acoustics on occasion... Despite the penchant by so many to use so many precisely defined terms as slang and to fail to properly recognize the implications of the imprecise use of such terms. We have variously seen "reverberation", the ETC, and various other response models, etc. similarly characterized with the result being not an increase understanding, but rather the exact opposite, the expansion of many folks coming here to learn either being more confused or being misinformed, with many of the efects being such that applied actions based upon such information may be in error.

You have not posited the study of any reflections in an anechoic chamber, which by practical definition is designed precisely to eliminate any such behavior properly defined as a "reflection".

Thus, practically speaking, there are NO reflections in an anechoic chamber, and your examples utilize none. They utilize delayed signals in order to SIMULATE reflections.

But there are absolutely NO reflections in their experiment as structured nor in the anechoic chamber. Thus no "reflection" can be, nor was, evaluated.

Now, if you want to correctly posit that delayed signals assumed to be incident upon an ideal reflective surface and as such defined to be identical to the originating signal (which deviates from any real signal in terms of both reactive and real components) defined within the scope of the experiment to be the approximation of a "reflection", as well as another identical signal defined within the scope of the experiment to be equivalent to a "direct" signal, and the relationships of these variously delayed signals evaluated, you would have come close to describing what actually transpired.

They made no errors, as their write up correctly and appropriately described the variously delayed direct signals designed to simulate reflections. They did not make the mistake of characterizing them as actual reflections. The problem is not in the AES paper,but in the misrepresentation of what they actually did.

But, as stated, and as modeled, NO actual reflections were present nor evaluated. ...But they did evaluate various direct signals featuring differing delay times in an effort to simulate the interaction (in some manner) of direct and delayed signals that makes what actually happened in the anechoic chamber and in the experiment easier to accurately understand.

Similarly this is a rather curious experiment for one to be holding up who also feels that one must use a bandwidth limited ETC in order to evaluate reflections that would necessarily assume that a broadband signal, incident upon a boundary, would necessarily be so modified as to have to necessarily examine the spectral composition of the reflected energy under the assumption the the reflected energy would be significantly altered from that of the incident source.

Now for the rest of us very familiar with the ETC and with best practices dating back at least 40+ years, a bandwidth limited ETC was a very handy diagnostic tool by which to evaluate heretofore unknown boundaries in existing spaces where one was charged with effecting the acoustical response. And if a boundary exhibited a non uniform broadband spectral response, either modification or replacement of the boundary, or modification via the application of a complimentary treatment would be in order to remediate such a condition.

Thus it was best practice to 'begin' with a uniform broadband specular response, as well as to use treatments that likewise behaved in a broadband manner in order to avoid coloration of the direct signal. (The only special case deviation from this would be accepted in the extremely unusual case if a source could be definitively demonstrated to exhibit a non-broadband character, and to this it was matched with a similarly performing complimentary treatment.)

Thus one wonders why, when those following the best practices where specularly broadband boundaries and treatments are utilized, and the resulting reflected energy was essentially equal to the incident energy, that it is improper to utilize a broadband ETC. But in your structured experiment, no provisions are made to modify the reflected energies to modify the spectral content of the reflected energy in order to comply with your assumed behavior for which you fault others who have been aware of such potentialities and who have addressed such issues as a prerequisite to proceeding with a project. And no fundamental provisions are made to evaluate said reflected energies in terms of a bandwidth limited manner.

Or is it that only others are so bound by such criticism and such measurement policies? And in order to accurately model and simulate such behavior such alleged fundamental issues are able to be conveniently ignored. It would seem that if one is going to make the rules, that they would also play by them.

The fact is that when Toole published his paper delineating the concerns over ignorantly applying a broadband measurement in the late 1980s, some 20+ years after the broadband and band limited ETC measurement has been introduced, all those using it were already long aware of any issues - seeing as the broadband and band-limited capabilities of the tool had long been used precisely to analyze and identify such anomalies for 20+ years already, were literally met with a yawn. While perhaps profound to those yet unaware, it was old news to those already familiar and using the tool...which interesting as the tool was only available on at most 3 or 4 (with only a handful of the B&K model having ever been produced) platforms. As such concerns were already well understood and the diagnostic capabilities of the tool well understood and presented by Dick Heyser even prior to the release of the technology under license from the Jet Propulsion Lab managed by Don Davis. What is ironic was that at the same time as the release of Tooles paper identifying the 'obvious', the 'big' debate in the pro SR world and AES was of Don Davis' assertions, the same person responsible for the first 1/3 octave equalizer while with Altec based on the acoustic and psycho-acoustic research of Dr. Boner at UnivTXAustin, that one could not effectively EQ non-minimum phase signals - in other words, negating the very technique that ost of the entire industry had pretty much embraced as THE way to address locally variable speaker-room and speaker-speaker interactions! And that debate over the fundamental limitations of what an EQ could do and what it could not would dominate acoustical world for about 3-4 years until about 1991-3, when as quickly as 50-60 channels of EQ had appeared in traveling pro SR racks, they disappeared on all but a few direct channels....well, except for in the audiophile world where such a suggestion still raises squeals of objection!

And as far as the utterly ignorant claim that he ETC is frequency blind, that is simply FALSE. The basic display is constructed specifically as a time versus gain display, but the information contained within is the complex representation of both the impulse and doublet response - and as anyone familiar with the mapping of topological spaces from one to another, frequency is a 'simple' matter of the convolution of the signal via the use of several transforms.

Whereas the ETC allows both the 'contents' of the real and imaginary domains constituted by the impulse and doublet response respectively to be practically shown in a 'summed' manner, it is no more frequency constrained than the impulse response itself.

One has simply chosen the manner in which they wish the information displayed that is most useful. It is a rather trivial mathematical process (or, given the platforms, the push of a button) by which to convolve the measured data into the frequency domain and to display the frequency analogue in terms of the frequency domain and to display the real domain coincident and imaginary domain quadrature response.

And this should be readily apparent to anyone ACTUALLY familiar with the B&K Domain map that has been around for at least 30 years since I was first exposed to it. And the people I know actively employing such tools not only understand the use of the tool, but they understand the relationship of but one useful display of information along with the other available responses that display other complimentary perspectives of the same raw data.

It strikes me as a bit of hysteria when someone shows up whose sole authority is that they have read some hearsay source and tries to discredit a measurement on the basis that is does not effectively supplant every other convolution or perspective. I wonder, is that why most platforms, and certainly all of the major 'serious' platforms, include the full array of responses as defined in the B&K Domain map... I mean, who is silly enough to make that mistake and not be as smart as the tools and know how to convolve results into whatever perspective most adequately shows one the information needed on the basis of one's understanding the role and utility of each measurement?... I wonder....

So lest anyone panic, a thermometer will not generally tell you time of day or the date. So, on the basis of allegations made earlier, you might want to throw out your thermometers. It also will not think for you.
Edited by dragonfyr - 6/30/12 at 10:28pm
post #37 of 135
Quote:
Originally Posted by amirm View Post

I don't think these people deserved the insults:
Bigus:
sdurani
alittletank:
Dennis Erskine
"redirect" rolleyes.gif

I wasn't talking about them:
Quote:
Originally Posted by amirm View Post

My arch-nemeses? I love those two guys! Without them we wouldn't have these discussions. Someone has to play that role. Sure, we could all do with less insults and more constructive discussion but please don't confuse this as some kind of personal fight for me.
post #38 of 135
Quote:
Originally Posted by dragonfyr View Post

Just occasionally words have meaning. It even happens in acoustics on occasion... Despite the penchant by so many to use so many precisely defined terms as slang and to fail to properly recognize the implications of the imprecise use of such terms. We have variously seen "reverberation", the ETC, and various other response models, etc. similarly characterized with the result being not an increase understanding, but rather the exact opposite, the expansion of many folks coming here to learn either being more confused or being misinformed, with many of the efects being such that applied actions based upon such information may be in error.
In other words, you misunderstood my reference to a very common testing method for reflections. It happens. Next time please ask for clarification before making fun of it. If I still said the same thing, then you can laugh smile.gif. As it is, it made it look like you are unfamiliar with the basics of how this research is done or else, the reference to anechoic chamber would have made sense.
Quote:
You have not posited the study of any reflections in an anechoic chamber, which by practical definition is designed precisely to eliminate any such behavior properly defined as a "reflection". Thus, practically speaking, there are NO reflections in an anechoic chamber, and your examples utilize none. They utilize delayed signals in order to SIMULATE reflections.
I have made this point many times so I don't know why it keeps getting lost. "I" play no role in this. I didn't run the tests. I quoted tests by top researchers in the industry. Your beef is ultimately with them. But yes, they are simulations. But extremely good ones in that they let us control one parameter at a time and with very high precision. Since the test room is otherwise anechoic, we can test a single reflection and only hear its effect and not the rest of the reflections which would occur in a real room.
Quote:
But there are absolutely NO reflections in their experiment as structured nor in the anechoic chamber. Thus no "reflection" can be, nor was, evaluated... They made no errors, as their write up correctly and appropriately described the variously delayed direct signals designed to simulate reflections. They did not make the mistake of characterizing them as actual reflections. The problem is not in the AES paper,but in the misrepresentation of what they actually did.
I am using identical terminology as is shared by researchers in this field. From the JASA report:

"Experiments were performed to measure two kinds of suppression threshold for running speech:
echo threshold, defined here as the minimum level at which it was possible to detect that an echo
was present, and masked threshold, defined as the minimum level at which it was possible to detect
that a lagging sound was present at all. Both thresholds were measured using a geometry in which
sound sources and reflections were distributed over the horizontal plane (left, front, and right
locations) and a geometry in which they were distributed over the median sagittal plane (front,
overhead, and rear locations)."


And from Dr. Toole's paper:

"A review of the scientific literature reveals that natural reflections in small rooms are at levels where they are perceptible, and their subjectively judged effects range from neutral to positive."

See? They call it a reflection. In the research paper they describe how they measured that and that provides the context so that people know if it was a simulation in anechoic environment or not. So while I hear what you are saying, it goes against the grain of the language and research conducted in this area. The use of the term reflection in simulated environment is absolutely common and causes no concern among the experts communicating such concepts. You are welcome to have a contrarian view. Please share with us what listening test data you have involving single reflections that are not done in anechoic chamber and disagree with this finding. If you have none, please excuse us for using what is in front of us smile.gif.
post #39 of 135
You really would do well to take some time to study formal acoustics and acoustical measurement concepts and methodologies.

Apparently you are under the impression that in order to make anechoic measurements that an anechoic chamber must be used.

The irony is that most multi-stimulus measurements do NOT require the use of an anechoic chamber.

A far as "any listening or test data involving single reflections", if I simply count those performed at the various SynAudCon functions, those alone would amount to more than you have even read about. And if you want to "see" the results of many of them, go read Sound System Engineering, or Everest's Master Handbook, as Don published many of them and Everest sourced almost ALL of his measurements from SynAudCon functions!

But to the point of anechoic measurements in a non-anechoic space, I will leave it to you to do more searches regarding the use and advantages of TEF and TDS specifically in doing exactly that. Ironically, 'almost' the same thing can be done with FFTs by windowing the results, although with a lessening of the effective resolution.

And in so researching this, you MIGHT also discover that there is a large group in formal acoustics who DO expect one to mean what the say and to say what they mean, or at least to clearly explain the proper use in context before one devolves into substituting terms as slang in place of properly defined and utilized terms but only withing the context of a group who is clear as to the meaning and use of formal definitions..
post #40 of 135
Quote:
Originally Posted by dragonfyr View Post

A far as "any listening or test data involving single reflections", if I simply count those performed at the various SynAudCon functions, those alone would amount to more than you have even read about. And if you want to "see" the results of many of them, go read Sound System Engineering, or Everest's Master Handbook, as Don published many of them and Everest sourced almost ALL of his measurements from SynAudCon functions!
Did you say "measurements?" I was not talking about measurements. We are talking about how humans hear the effect of reflections. You are honestly telling us that a meter measurement does the same thing? What meter measurement shows results like these posted earlier:

i-cd4h8QV-X2.jpg
Your meter measurements show non-linear behavior like those? if so, do you think these people are too stupid to have gone to these extremes to test these effects using people instead of sticking a meter in there and following the books above?

You do accept this is ultimately about how we hear sound in our rooms, yes? Not what a meter thinks of the sound. Yes?
Quote:
But to the point of anechoic measurements in a non-anechoic space, I will leave it to you to do more searches regarding the use and advantages of TEF and TDS specifically in doing exactly that. Ironically, 'almost' the same thing can be done with FFTs by windowing the results, although with a lessening of the effective resolution.
What do you mean "back to point of anechoic measurements?" There was no such discussion per above. The discussion again is how we hear. How could that be missed in such a short thread? Or are you are replacing a human with TEF and TDS? It would be amazing revelation that we can replace humans with TEF and TDS analyzers. Would you point me to the page in the books you cited that explains how we have obsoleted listening tests and that meters are now just as good at telling us what distortions are audible and by how much?
Quote:
And in so researching this, you MIGHT also discover that there is a large group in formal acoustics who DO expect one to mean what the say and to say what they mean, or at least to clearly explain the proper use in context before one devolves into substituting terms as slang in place of properly defined and utilized terms but only withing the context of a group who is clear as to the meaning and use of formal definitions..
I already addressed this Dragon. You are reliving the fact that you are not familiar with the use of the language in this domain and protocols used for human testing. That is not an issue with me or the researchers in this field but your familiarity with anything to do with psychoacoustics of sound. Why else would you now think we are talking about measuring reflections when I even explained the topic in detail? It is like us discussing crash test results for cars and you still telling me the thickness of the metal in the hood. The latter may have something to do with crash test results but there is a long way between that data and how the car performs in the crash. A simulated one of that is miles ahead of your thickness measurement of said hood.

So please, if you are going to come back again, please post relevant data on listening test results that don't use anechoic chamber but arrive at different conclusions than the ones cited. Don't ask us to do the homework for you by giving us book names that don't even cover this topic and ask us to go and search for them to data that doesn't exist. It is your case to make, not our job to do your homework smile.gif. It should not be beneath you to find the relevant sections and quote them for us. If you can't or are unwilling, please say so crisply and we will continue the discussion without you.
post #41 of 135
Quote:
Originally Posted by amirm View Post

Did you say "measurements?" I was not talking about measurements. We are talking about how humans hear the effect of reflections. You are honestly telling us that a meter measurement does the same thing?

amirm,
do you have documentation on how they are able to simulate diffused reflections from a single source (loudspeaker) like they have with respect to sparse reflections in the anechoic chamber? eg, dense diffused Broadband reflections like that of Blackbird C? is there no published data on anechoic-chamber Broadband diffused (simulated) reflections - the very type of broadband (non-colored) that toole insists if on such treatment is utilized?
post #42 of 135
i-QJKMz48-XL.png

well i sure hoped they utilized the ETC to measure the ACTUAL signals at the receiver (mic) in the anechoic chamber. just because your electronics insist that you're delaying the signal by X ms, doesn't mean the signal received at the listening position is automatically delayed by the same amount. surely they utilized the ETC to verify their equipment was functioning correctly based on how the signal ACTUALLY arrived at the receiver in the anechoic chamber vs blindly assuming.
post #43 of 135
Quote:
Originally Posted by localhost127 View Post

i-QJKMz48-XL.png
well i sure hoped they utilized the ETC to measure the ACTUAL signals at the receiver (mic) in the anechoic chamber. just because your electronics insist that you're delaying the signal by X ms, doesn't mean the signal received at the listening position is automatically delayed by the same amount. surely they utilized the ETC to verify their equipment was functioning correctly based on how the signal ACTUALLY arrived at the receiver in the anechoic chamber vs blindly assuming.
"Receiver?" "Mic?" How can you also lose the plot? As I just explained, there is no "mic." There is a *person* sitting in a chair whose ear is located precisely at X distance to the speaker generating the sound. And yes, they were anal enough to force the subject to stay at that position: "A metal guidebar rested atop the subject’s head and helped the subject maintain a fixed head position."

Now if you pay attention to the graphs, they horizontal scale is in milliseconds. To compute what that means in distance from a reflection, we can use the speed of sound. If you are saying in above that the speed of sound changes when I change the delay up stream of the speaker, then that would be a wonderful explanation for us to see! It would also be wonderful to see why the "energy" in the room, i.e. the first letter in "ETC" measurement, is necessary to determine such delay times. You think the timing of sound changes when I apply ETC integration to it than if I don't? If so, do you have a measurement to show that?
post #44 of 135
Quote:
Originally Posted by localhost127 View Post

amirm,
Local, smile.gif
Quote:
do you have documentation on how they are able to simulate diffused reflections from a single source (loudspeaker) like they have with respect to sparse reflections in the anechoic chamber? eg, dense diffused Broadband reflections like that of Blackbird C? is there no published data on anechoic-chamber Broadband diffused (simulated) reflections - the very type of broadband (non-colored) that toole insists if on such treatment is utilized?
As I post from the Dr. D'Antonio presentation slide, they commissioned perceptual tests of that room. Yet, I have seen no published results. Maybe they are having a hard time because said diffusers now have curtains in front of them! http://www.avsforum.com/t/1413173/does-sound-sounds-better-in-a-room-full-of-furniture-and-stuff-or-without/90#post_22155366 smile.gif. Heck, we don't even have measurements anymore of that room with said curtains. So there is really no "there there" anymore.

I am glad however that you brought up this point at it absolutely is the job of the people selling such products/room configurations to produce data showing their efficacy for the intended purpose, i.e. to improve the sound fidelity. Unfortunately if you go to any of these company web sites, you only see measurements of their alpha (absorption/diffision coefficient) as opposed to any listening tests showing whether they improve what we hear. They like us to believe a graph and not our ears. Now if listening tests showed data proportional to those graphs, that would be cool. But the listening tests portray a picture that is very different.

But sure, if you want to present us with listening test data you have that shows the efficacy, let's see them. Otherwise, I hope you are not relying on absence of data on your part to prove anything.
post #45 of 135
Quote:
Originally Posted by audiophilesavant View Post

The issue should not be which we should prefer, but rather how to achieve that which we do prefer.

I can't argue that people should be forced to listen the way so-called "experts" tell them to, but there is something else to consider: People sometimes change their mind, and listeners can become more sophisticated over time. A well-treated listening room can be an acquired taste, and appreciated fully only after you live with it for a while.

--Ethan
post #46 of 135
Quote:
Originally Posted by amirm View Post

I don't know how you could say that Sanjay.
500 pages into his book he suggests a few treatment plans. Each of the diagrams leaves one area blank: the side-wall first reflection points of the L/C/R speakers. I'm 90% into his book, he's explained about human hearing, recordings, rooms, speakers, reflections, treatments, etc, but he doesn't tell me how I should be treating the most important reflections. After arming me with a lifetime's worth of research and collected data, he still leaves the decision of whether to absorb, diffuse or reflect completely up to what I prefer. That's how I define 'directional'.
Quote:
Originally Posted by amirm View Post

If you sit through a presentation with him, or speak to him, you see that the case he presents is anything but directional.
Then you and I have simply had different experiences with him. Nothing more complicated than that.
Quote:
Originally Posted by amirm View Post

He will demonstrate his case to you with extreme conviction. He will tell you in extremely direct manner how many of the current assumptions about acoustics are flat wrong. ...He allocates considerable amount of time to this topic in his presentations and frankly, you can't leave the room until you concede smile.gif.
No offense Amir, but you're describing your posts, not Toole's writing.
Quote:
Originally Posted by amirm View Post

And why the resistance?
Human nature. People will sometimes resist the best of advice if they feel it is being rammed down their throat.
post #47 of 135
Quote:
Originally Posted by amirm View Post

That is true. Kevin does disagree. As I noted, once you know the science and then disagree, all is well. But please don't skip that step.
What science is necessary in order to decide that one prefers either sidewall absorption or reflection? That's an empirical choice.
post #48 of 135
Quote:
Originally Posted by sdurani View Post

No offense Amir, but you're describing your posts, not Toole's writing.
Writing? I thought I was clear in saying that I was expressing my experience in talking to him and listening to him in person. And not once but multiple times across many, many hours. And not just him but other researchers at Harman who have worked with him for years. You can call me a liar but please don't change my answer to something else as to say we both are talking about a book and for some reason, your read of said book is more accurate than mine. It is wonderful that you are reading the book and I have no qualms about your views about Dr. Toole's book be different. Just not the same as actually listening to him and having him lament about all the myths that are talked about in these forums.

Even in the case of his writings, you are walking away with a very different conclusion than me. This is a graph from his AES paper on effects of reflection on speech:

i-VKC5CNZ-XL.png
In what way this is not instructive and only directional? How could someone take that conclusion and say, "he is saying both alternatives are fine." That is not what the graph says. The graph says you can't put speech and "reflections being bad" in the same sentence. You can certainly choose to absorb those reflections and with it, lose your amplification power and intelligibility. He is not going to call the police on you and he will even mention that if you insist, you can go there. But that is a far cry from him providing "directional" advice.

Now, this is the type of "color" that you will hear if you spoke to him in person. From his CEDIA course:

"Sometimes these (modular bass absorbers) are called "bass traps." The problem with the name is that some of them don't "trap" much of anything excpet cash from unwiiting purchasers."

You see this style of discussion and disdain for common practices and advice on this forum in his book? No. There are things we can doubt. But this point is not one of them. The man has conviction for certain things after 40 years of doing this and this is one of them.

For your proof point, you seem to be saying that if he doesn't give you precise answers on what to do, then what he is saying is not definite and instructive. Dr. Toole addresses this in his into to the book:

"It is hoped that the presentation style and language serve their needs. This book is not a cookbook. Sadly, such simplifications—and several have been attempted— end up being oversimplifications."

His goal is to teach you how to fish. If with that knowledge you still can't catch fish, well, go back and read it again smile.gif. If that fails, then take an in-person class with him. The CEDIA class while still full of theory and science, is more instructive. Even in his book, Chapter 22 comes very close to handing you a fish by give you two complete set ups in Figure 22.3. Perhaps you have not reached that far in the book.
Quote:
People will sometimes resist the best of advice if they feel it is being rammed down their throat.
True. But I am not going to reposition the man's true teachings as being wishy washy as to get more people to listen. That will be a disservice to the compelling case he makes for his point of view which by the way, he will readily admit to be an "opinion." To be clear, I don't write these posts for the obstinate few but for the many who are reading them but don't have the time or inclination to go through the learning exercise that I went through. And to offset the bludgeoning that has been going on as of late to force people to run ETC and "surgically" deal them as someone mentioned in the other thread. Hope that's alright with you smile.gif.
.
post #49 of 135
Quote:
Originally Posted by RUR View Post

What science is necessary in order to decide that one prefers either sidewall absorption or reflection? That's an empirical choice.
That "choice" in this context is infinite in nature and quite involved in scope. You are going to try all of those permuations and combinations? Why not rule out some based on research? For example research says that if you are going to absorb side reflections, you want to use a broadband absorber. This usually means 4+ inch thick fiberglass product. Why go and spend time testing 1 and 2 inch devices? And the cost of acquiring all of the products? Diffusers for example can be expensive to buy.

I think folks come here thirsty for knowledge as to avoid the aggravation of performing their own extensive research. We don't go designing five different speakers ourselves to then decide what we like. Yet folks in this space tend to want to do that with acoustic solutions. Why not read the research and accept some of it as goodness that has consensus and focus your energy on what has two good choices?

But sure, in that case, I was expressing my personal opinion/preference which is to understand what I am trying to experiment with smile.gif. It tells me that certain data is wrong and hence, there may be a problem with my experimentation. It also lets me judge other people's explanation of science. If I know that power = volts * amps and someone says they doubled the voltage and power only goes up by 20%, I would know it and won't listen to them.
post #50 of 135
Thread Starter 
Quote:
Originally Posted by dragonfyr View Post

And as far as the utterly ignorant claim that he ETC is frequency blind, that is simply FALSE. The basic display is constructed specifically as a time versus gain display, but the information contained within is the complex representation of both the impulse and doublet response - and as anyone familiar with the mapping of topological spaces from one to another, frequency is a 'simple' matter of the convolution of the signal via the use of several transforms.

Whereas the ETC allows both the 'contents' of the real and imaginary domains constituted by the impulse and doublet response respectively to be practically shown in a 'summed' manner, it is no more frequency constrained than the impulse response itself.

One has simply chosen the manner in which they wish the information displayed that is most useful. It is a rather trivial mathematical process (or, given the platforms, the push of a button) by which to convolve the measured data into the frequency domain and to display the frequency analogue in terms of the frequency domain and to display the real domain coincident and imaginary domain quadrature response.

This definition is from the Rane website:

ETC (energy time curve) Originally a three-dimensional graphical plot of acoustic response where frequency, energy and time represent the three axes. Today it is more commonly seen as a two-dimensional graph with energy (in dB-SPL) and time being the axes. In simplest terms it is a plot of the envelope, or instantaneous amplitude decay of the test signal.

It seems like you can show frequency, time, and dB at the same time. Is this type of graph ever used any more?
post #51 of 135
Quote:
Originally Posted by amirm View Post


As I post from the Dr. D'Antonio presentation slide, they commissioned perceptual tests of that room. Yet, I have seen no published results. Maybe they are having a hard time because said diffusers now have curtains in front of them!

Heck, we don't even have measurements anymore of that room with said curtains. So there is really no "there there" anymore.

LMAO!

Blackbird is considered to be the finest example of the reflection rich environment in existence. PERIOD.

It was designed to be such and the results were indeed achieved!

And yes, SOME of us, to the notable exception of the one who seems to do the most talking, have indeed heard it. And it works VERY WELL INDEED for a reflection rich environment. Ironically it seems that ever he who does so much talking has even been able, through searches, to cut and paste George Massenburg's comments to that effect.

And apparently (apparently???) our learned friend who has invested "several days" becoming familiar with this 'stuff' is not familiar with the best practices proof of performance procedure and how Peter D'Antonio and others of his caliber operate. ...As if they would simply declare it finished as soon as the polyurethane dried and walk off. One really could have benefited substantially by allocating 1 or 2 more days to the effort...

But as is so common here, the original intent of the room has, BY VIRTUE OF THE PREFERENCES OF THOSE USING THE ROOM, been effectively rejected. Toole's proffered response that we are told is SO completely preferred , not by a unanimous tally, but by a majority of listeners, has been REJECTED by the trained ears of both engineers and performers operating in the room and effectively converted to a quasi-LEDE response by the conversion of the lateral diffusors to absorbers by the application of blankets placed over the diffusors (and if one are not familiar with this technique of using quadratic diffusors as absorbers, please read chapter 9 of Acoustic Absorbers and Diffusors and spare us the repeated astonishment at how such devices operate).

Apparently what most confuses our friend is that - instead of generating panels and surveys and all sorts of listening preference survey results in order to support their preference, that the professionals have simply covered the diffusors, converted them to absorbers, and then upon listening decided they prefer the response - all without setting up panels and surveys boards and conducting formal listening tests. In stead they have had the unmitigated audacity to simply do it and to trust their own ears, and have, to the chagrin of a few, rejected what they and Toole maintain they should, will, must prefer.

And I think it is understandable that those who have made the case that one WILL and MUST prefer a reflection rich response, that some , for what must be very confusing reasons, have freely chosen an alternative response. The heresy!

The fact that continues to be confused and misrepresented is that while a Toole consistent reflection rich environment was indeed designed and delivered, that the preponderance of the "professional trained ears" REJECT the large amorphous imprecise image that we are repeatedly told folks will , and in fact, must like, and they have instead rather soundly REJECTED such a response and in converting the lateral diffusors into absorbers, reduced the early reflection rich response and effectively achieved - contrary to the designed goal - imposed their taste upon the room - to the chagrin of the Toole disciples who are having one heck of a time accepting this rather dramatic real life case of professionals taking a exception to their claims!

For let's review the situation and choices one has as is well described by Toole himself:

The Acoustical Design of Home Theaters
By Floyd E. Toole, Ph.D.

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.
(p.4)



So, it is indeed a mater of choice, as to the degree that the timbral accuracy is maintained, BOTH are acknowledged to be valid choices which are in fact a "matter of choice".

And thus the ONLY REAL point of actual contention here that sticks in the craw of Toole's disciples is the FACT that the trained professionals have REJECTED the assertion that the reflection rich environment will be found "by many, (to be) more realistic".

Which is really not surprising at all when you think of the response that is being generated by each approach.

Toole is playing to a crowd listening FOR PLEASURE to SURROUND music and movies. Here they like BIG FXs and a Large image. Things seem larger and they feel a sense of greater envelopment, which I can imagine would be a great way to experience a star exploding of if you are on a ride at 6 Flags.

However, is it really a surprise that trained professionals might prefer an "experience (that is) more intimate, and the imaging tighter and more precise"?

You see, it IS a matter of preference. And what may be considered optimal by some for SURROUND music and movie watching, may NOT be the preferred response for all.

The fundamental difference between the party advocating the Toole reflection rich response and myself, is that I acknowledge the matter of Preference, taste and choice. And I, in particular, understand the preference for an "experience (that is) more intimate, and the imaging tighter and more precise",

I also acknowledge that many may actually like the more amorphous 'large' imprecise image as well. (And I would encourage them to pursue the realization of such a response in their establishment.)

I am just not here berating you with survey results and cut and past charts in an attempt to coerce you into freely choosing the preference that has apparently already been made FOR you by others and by virtue of some surveys.

Instead, as with the additional available responses, we are here with the idea that one does have choice and that one is free to choose among a variety of vetted acoustical responses. And to my mind it then seems incumbent that one, instead of being berated and bullied into deciding what they MUST prefer, that they should avail themselves of the opportunities to become familiar with the array of response choices, and after THEY freely decide upon which response they prefer and which is most practical to achieve given their particular circumstances, to understand the mechanics by which a desired response may be achieved, and to employ the available tools and techniques in order to best achieve such a response.

The fundamental difference? Ironically Devo captured the concept well. I advocate an informed freedom of choice, where others, citing the tyranny of surveys and what they maintain is the incontrovertible preference of the majority, advocate a pre-ordained one size fits all 'freedom From choice'.







Oh, and as far as the ETC, YES, the available manner in which the information may be graphically displayed is, to my mind, rather remarkable. And to cite a rather arcane addendum, I spent too many years as an undergrad and grad student manipulating 'imaginary' numbers, memorizing that which we were told they corresponded and NEVER receiving useful clarification as to what in hell an "imaginary" number really was, or to what it corresponded in a "real" world.

The moment I saw a 3 space depiction of the Analytic complete with its constituent parts displayed the lights went ON and what had previously been rendered "imaginary" became apparent to be anything BUT imaginary, and their significance was instantly not only rather obvious, but, and feel free to doubt this, useful!

I have quite a bit of information and there is more in the 3rd edition of Sound System Engineering.

If anyone is serious to pursue what I personally find to be a very useful and interesting topic (no, sorry, I do NOT have any surveys conducted by others with which I will attempt to tell you that YOU MUST also find the subject fascinating...) but you are welcome to PM me with an email address and I can send you some additional info as I am able...)

Also, for another view of but a tip of the proverbial iceburg, may I suggest folks query Dick Heyser's review of the Klipschhorn published in Audio Magazine. It is able to be found online, but if you can't , PM me... You will see that the information that is able to ascertained from the Analytic goes FAR beyond what many imagine and which has been even alluded to here. The amazing aspect is that so many are still so ignore-ant of both the measurements and what they are able to render understandable. (And for the benefit of the few here still confused over the role of measurements - they provide additional information in, ideally, a form that augments one's ability to make informed decisions. They are NOT,as some imagine, a substitute for the experience, or of listening, or, as apparently is the case with many, thinking.)

In fact, I wouldn't mind there being a thread where the measurements can be presented in a more thorough manner, from theory to some of the more common, and even uncommon, applications...but if another forum is an indication, such attempts quickly become dominated by those who lack any understanding of what it is who assert that there is no place for such nonsense and the thread simply devolves into another typical thread.
Edited by dragonfyr - 7/1/12 at 2:50pm
post #52 of 135
Quote:
Originally Posted by amirm View Post

I thought I was clear in saying that I was expressing my experience in talking to him and listening to him in person.
To which I was clear in replying that "you and I have simply had different experiences with him". Apparently you've been privy an "extreme" version of him that I haven't.

The 'you can't leave the room thread until you concede' approach is something you're projecting onto him, evident from your posting history. The reason I mention your posts is because I don't know you personally, so I can only go by what you've written.
Quote:
Originally Posted by amirm View Post

In what way this is not instructive and only directional?
It tells you what general preferences are, not what you must do; i.e., it gives you direction, but doesn't provide you with the destination. That's up to you. See the earlier example of Kevin Voecks (just don't lean against the side walls of his room).
post #53 of 135
Quote:
Originally Posted by amirm View Post

That "choice" in this context is infinite in nature and quite involved in scope. You are going to try all of those permuations and combinations? Why not rule out some based on research? For example research says that if you are going to absorb side reflections, you want to use a broadband absorber. This usually means 4+ inch thick fiberglass product. Why go and spend time testing 1 and 2 inch devices? And the cost of acquiring all of the products? Diffusers for example can be expensive to buy.
Although we disagree about the complexity involved in selecting and applying sidewall treatments adequate to an informed choice, I take your point. I thought you might be referring to Toole's preferential research.
Quote:
Why not read the research and accept some of it as goodness that has consensus and focus your energy on what has two good choices?
That depends. If you're now referring to Toole's research regarding sidewall absorption, consensus does not a universal fact make.
Edited by RUR - 7/1/12 at 3:37pm
post #54 of 135
Quote:
Originally Posted by kromkamp View Post

I don't think the relevant question is what priority to assign treatments on different surfaces (like if your budget is limited or something) - rather the question is what type/quantity of treatment is appropriate for each surface. I apologize if my statement of "relative importance" suggested otherwise (as I could see how it could, perhaps a poor choice of words on my part)
Thanx for clarifying; as you guessed, I took "relative importance" to mean some sort of hierarchy.

As for the type/quantity of treatment, I think that has more to do with what's appropriate to your goal rather than what's appropriate for each surface. If you look at the quote that audiophilesavant posted earlier, you'll see that dampening a room will give you a more intimate experience with tighter imaging, while allowing for reflections will yield a more spacious illusion that many find more realistic. Since our human hearing senses spaciousness primarily from lateral reflections, the choice of how whether to absorb side wall reflections or not comes down to the experience you prefer. Same surface, different treatment decisions; based on goal, not surface.
post #55 of 135
Quote:
Originally Posted by RUR View Post

That depends. If you're now referring to Toole's research regarding sidewall absorption, consensus does not a universal fact make.
It is not just his research. It is the culmination of research by many. That aside, you live with consensus all the time. The psychoacoutics model in MP3/AAC encoder is built that way. Heck, the entire design of the codec comes that way. You are throwing out a lot of science if you want to ignore consensus.

I was once in Las Vegas doing email and the TV was on the casino channel and they were running educational clips. A segment comes up and the guy who is in it starts with: "you are not special!" I am thinking what is that about? He goes on, "if a pretty girl comes up to you and smiles, don't think she has fallen in love with you because you are that good looking. She is either a prostitute or is going to rob you later! You are not special!" smile.gif So sure, if you want to consider to be unique such that research that is specifically performed to characterize human being preference doesn't apply to you, by all means, conduct your own personal tests and report back. I am sure we would all learn from that. The data here is compelling but not absolute.

BTW, your reaction is a natural one to Harman research. People read the word "preference" and automatically think this is like tasting food and that you may not like Sushi like I do. Then one day you are fortunate enough as I was and sit through one of their (blind) listening tests and you find yourself voting just like the others! You think this is an exception. So next time you are there you take the test again. And once more you vote like others. Then you realize, well, that you may not so special biggrin.gif.

As to Kevin, he is a speaker designer. He has training that you and I do not have. I am sure his ears are forever analyzing the sound of the speaker. I am trained in compression systems. There are things there that drive me off the wall and most people won't even notice them. So please be a bit cautious in following Kevin. He indeed, is special. And a very good friend smile.gif.
post #56 of 135
Quote:
Originally Posted by dragonfyr View Post

LMAO!
Blackbird is considered to be the finest example of the reflection rich environment in existence. PERIOD. It was designed to be such and the results were indeed achieved!
And yes, SOME of us, to the notable exception of the one who seems to do the most talking, have indeed heard it. And it works VERY WELL INDEED for a reflection rich environment. Ironically it seems that ever he who does so much talking has even been able, through searches, to cut and paste George Massenburg's comments to that effect.
Please let's have the facts straight. I found the comment from chasing where Localhost cut and paste George's opinion, only to find that he had left the sentence where they have put curtains in front of the 4 foot deep diffusers. So you have a beef about folks cutting and pasting info, especially when they leave out critical parts of the quote, Localhost is your man smile.gif.

As for me, I have no criticism of that room. As you correctly state, I have not been in it. I am however highly critical of you two constantly posting it. For one thing, it has no relevance to anything people do here as no one is going to put 4 foot deep diffusers on the walls. Second, the customer who had the room built, has since modified it with said curtains. So whatever you think of the sound is dwarfed by the customer who has to use it everyday. Third, Dr. D'Antonio and his company that built it for them says subjective testing is required to know if it is a good design. And for proof of why that is necessary, quotes Dr. Toole. So all in all, it is the worst example you could put forward for whatever case you are trying to make. Which frankly is clear as mud per my first point.

Looking online here is another point of view on the room: http://www.gearslutz.com/board/7007412-post7.html:

":And just to add to the original question; a dead (anechoic) room is not considered pleasant or “neutral” by most people (although some enjoy dead rooms) and this is where the fun begins, how to keep a room accurate and neutral but still not “dead” sounding (when listening to the speakers). This has been the challenge and so far, and LEDE/RFZ and perhaps CID are some of the concepts available to achieve this. The room at Blackbird, although interesting and completely wild, is still considered relatively dead by some of the people who has been there. Since there’s nothing above -30 dB after the direct sound, it is obviously a very accurate reproduction but still quite dead sounding because the lack of reflections of significant strength."

So maybe RUR is right and you are special and like the room and others do not. smile.gif
post #57 of 135
Quote:
Originally Posted by amirm View Post

BTW, your reaction is a natural one to Harman research. People read the word "preference" and automatically think this is like tasting food and that you may not like Sushi like I do.
Because that's exactly what it's like! Or is Kevin's preference for absorption "incorrect" in some way?

pre·fer: to like better or best

Because it's better.
To me.
Not others.

To paraphrase Sanjay's apt analogy: Simply because Billboard has a consensus #1 song doesn't mean that it's everyone's favorite.
Quote:
As to Kevin, he is a speaker designer. He has training that you and I do not have. I am sure his ears are forever analyzing the sound of the speaker. I am trained in compression systems. There are things there that drive me off the wall and most people won't even notice them. So please be a bit cautious in following Kevin. He indeed, is special. And a very good friend smile.gif.
I'm sure Kevin is extremely talented, but no special training is required. Floyd's characterization of the differences is spot on:

"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"

and those differences are not subtle.
post #58 of 135
You still seem to not fully get it.... You seem stuck on the fact that others have not embraced such reflection rich environments on the basis that some mistake must have been made or that some other anomalous behavior must be to blame.

And you seem a bit 'intimidated' by the mega diffusors...

One, they are large enough as to have an effective bandwidth down to ~120 Hz.

The treatment insures that any incident signal above 120 Hz is diffused to a maximal degree possible with the technology we have at our disposal.

...Actually to a much greater degree than anything Toole has proposed.

You see, Toole is NOT the only one who has proposed early reflection rich environments. And while you mention that others ignore aspects, you too ignore the fact that this response is yet another manifestation of the same attempt made by Bose with their direct-reflecting series of speakers. I know, I know, but I am associating "Bose" with this response. Yes, I am, as it SHOULD be. I am sorry that you have problems with the rest of their associated baggage. Its a shame you are not familiar with the REAL source of much of the Bose legend that resulted from Dr. Amir Bose's encounter with Don Davis in the University of Illinois after EV, Altec and Bose demonstrated their mid, high, and no Q SR systems and had them measured and listened to. And yes, I do have the measurements, and yes, there were lots of folks there to participate, witness and listen. Needless to say, two systems were VERY intelligible and exhibited what might be called 'hi fidelity'. One failed to do either. And only one company objected to having the resulting comparative measurements published (for 'internal' educational purposes among members and participants regarding a comparison of approaches - not marketing) and attempted to exert leverage by mentioning that they had contributed to the organizations activity underwriting, to which the response was rather swift in the form of receiving a refund in full of said 'donations' on the spot.

But in any event, the Bose direct reflecting series is an electromechanical attempt to create a broad uniform power response from a speaker as well as to stimulate an early reflection rich environment. And ironically it works very well. And the results , amazingly are quite consistent with the response preferred by Toole and the other proponents of early reflection rich environments - a LARGE amorphously defined image. Unfortunately in such environments, there is NO accurate precise image. But yes, it sure sounds 'big' and distributed for many listeners, and all the other things that some find attractive. It simply lacks an accurate defined image.

What you don't seem to get is that there is more than one way to very adequately achieve the same response.

And the applications of blankets over the difusors was not done by D'Antonio or George or any of the folks associated with the design team. The room works/worked GREAT as a reflection rich environment! The part of the equation that did not is the 'user's preference'. They just do not share the same unbridled enthusiasm for the large amorphous imprecise image as do you and your fellow survey participants - at least, those who similarly preferred it. They prefer a more accurate, precisely defined image rendered as a result of greater control of early arriving reflections - just as Floyd very accurately described - complimented by the rich diffuse 'later arriving' - in terms of milliseconds - diffuse soundfield creating a rich sense of space and envelopment. a quasi-LEDE response.

You see, there is no misunderstanding on the (most) part by any of the various participants. Each response model works just fine for its intended purpose and goals.

The continued misunderstanding seems to be simply that some refuse to acknowledge that more than a statistically insignificant number of people might prefer the alternative response models.

And while I can easily sit in such a room and listen to music or movies, I too find that I prefer the more accurate precisely defined image. Call it a result of many years exposure and familiarity, blame it on the humidity or the water. But nevertheless many do. As is reflected (sorry, couldn't help it) by the professional response in Blackbird.

The solution to this rabid proselytizing is simple. Toole, along with the other early reflection rich advocates, present and advocate another acoustic response model in addition to the other existing vetted acoustic response models. It is not a 'replacement'. It is another option better suited to some applications than perhaps others, but possessing no monopoly.

Now, you can cite all the marketing surveys regarding how many preferred it, but ultimately the surveys are no different than Ford or Chevy or Toyota waltzing out their statistics about how many trucks are still on the road, or what JDPower 's surveys say, or for that matter, what the results amortized over 30 years are for the Pepsi and Coke taste tests. According to each of their stats, they should be dominant, without the need to post such results if they were indeed as indicative of preference as the say, as they simply would not have much of an audience that was not already part of the choir.

But the bottomline, and the point you miss, is that it does not matter what someone else likes. It only matters what 'you' like. And if the response is one you like, then employ it.

Meanwhile the rest of use are more concerned with understanding the mechanics of how such a response is achieved/constructed and of the various underlying psycho-acoustic aspects that contribute to the response that some may or may not prefer with the primary interest in understanding the overall response model - just like we have with the other vetted response models.
Edited by dragonfyr - 7/1/12 at 7:25pm
post #59 of 135
Quote:
Originally Posted by amirm View Post

"Receiver?" "Mic?" How can you also lose the plot? As I just explained, there is no "mic." There is a *person* sitting in a chair whose ear is located precisely at X distance to the speaker generating the sound. And yes, they were anal enough to force the subject to stay at that position: "A metal guidebar rested atop the subject’s head and helped the subject maintain a fixed head position."
Now if you pay attention to the graphs, they horizontal scale is in milliseconds. To compute what that means in distance from a reflection, we can use the speed of sound. If you are saying in above that the speed of sound changes when I change the delay up stream of the speaker, then that would be a wonderful explanation for us to see! It would also be wonderful to see why the "energy" in the room, i.e. the first letter in "ETC" measurement, is necessary to determine such delay times. You think the timing of sound changes when I apply ETC integration to it than if I don't? If so, do you have a measurement to show that?

so you blindly trust the electronics with respect to the delay of the signal?
it's a simple question - did they utilize ACTUAL measurements at the listening position to CONFIRM their "electronic delay" was accurate? eg, not Blindly assume the electronic delay is doing its job and to verify that the simulated reflection arriving at the listening position was Truly X ms delayed (as to what the electronic delay was set to)?

it's quite a simple question. and look how defensive you're getting on about it.

if i apply an electronic delay to simulate (!) a reflection, i would at least utilize actual measurements at the listening position to verify my electronic delay was accurate. i don't need an entire paragraph of your commentary - a simple yes or no would do.
post #60 of 135
Quote:
Originally Posted by amirm View Post

Local, smile.gif
As I post from the Dr. D'Antonio presentation slide, they commissioned perceptual tests of that room. Yet, I have seen no published results. Maybe they are having a hard time because said diffusers now have curtains in front of them! http://www.avsforum.com/t/1413173/does-sound-sounds-better-in-a-room-full-of-furniture-and-stuff-or-without/90#post_22155366 smile.gif. Heck, we don't even have measurements anymore of that room with said curtains. So there is really no "there there" anymore.
I am glad however that you brought up this point at it absolutely is the job of the people selling such products/room configurations to produce data showing their efficacy for the intended purpose, i.e. to improve the sound fidelity. Unfortunately if you go to any of these company web sites, you only see measurements of their alpha (absorption/diffision coefficient) as opposed to any listening tests showing whether they improve what we hear. They like us to believe a graph and not our ears. Now if listening tests showed data proportional to those graphs, that would be cool. But the listening tests portray a picture that is very different.
But sure, if you want to present us with listening test data you have that shows the efficacy, let's see them. Otherwise, I hope you are not relying on absence of data on your part to prove anything.

that's strange - i didn't ask anything with respect to blackbird c's perceived response. i simply asked about toole's testing procedures regarding diffused simulated reflection(s), and whether they were done and How they were done.

here's my commentary again:
Quote:
Originally Posted by localhost127 
do you have documentation on how they are able to simulate diffused reflections from a single source (loudspeaker) like they have with respect to sparse reflections in the anechoic chamber? eg, dense diffused Broadband reflections like that of Blackbird C? is there no published data on anechoic-chamber Broadband diffused (simulated) reflections - the very type of broadband (non-colored) that toole insists if on such treatment is utilized?

im simply looking for any data on if and how toole simulated Diffused reflections in his anechoic chamber with a single (or multiple?) loudspeaker. did he simulate diffused sidewall reflections, or merely sparse reflections (via a single loudspeaker via a delayed signal). and if so, how did he simulate Broadband diffused reflections like that found in Blackbird C.

and just a side note, blackbird C's diffusers are nothing special other than the fact that they are BROADBAND - specifically the type of treatments toole calls for. basic physics - sound has size.
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