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Did Amir Change Your Mind About Anything?

It’s easy to make snide remarks like “yes- I do the opposite of what he says.”  And in some respects I agree, but if you do that, this is just going to be taken down. So I’m asking a serious question. Has ASR actually changed your opinion on anything?  For me, I would say 2 things. I am a conservatory-trained musician and I do trust my ears. But ASR has reminded me to double check my opinions on a piece of gear to make sure I’m not imagining improvements. Not to get into double blind testing, but just to keep in mind that the brain can be fooled and make doubly sure that I’m hearing what I think I’m hearing. The second is power conditioning. I went from an expensive box back to my wiremold and I really don’t think I can hear a difference. I think that now that I understand the engineering behind AC use in an audio component, I am not convinced that power conditioning affects the component output. I think. 
So please resist the urge to pile on. I think this could be a worthwhile discussion if that’s possible anymore. I hope it is. 

chayro

Showing 7 responses by britamerican

britamerican
52 posts
 

@amir_asr ,

 

 

Quick, tell me what frequencies in this graph are room modes, and which are boundary issues? Hint, there are some obvious ones that the Lyngdorf was not able to do anything with that are the boundary issues and those absolutely can be improved significantly with proper use of acoustic panels. That is simple physics. You are correct that multiple subs won’t get rid of your room modes completely, but they will soften them considerably and present more consistent bass across a larger listening space whereas room correction improvements will be more localized.

 

 

As a point of information, what Ansi-CTA-2034 uses for Front Wall and Rear wall is opposite what most audiophiles will call the front and rear wall. In 2034, for instance, the front wall bounce is the spatially average 0º, ± 10º, ± 20º, ± 30º horizontal responses and 0 degrees is pointing forward from the speaker, so when looking at the speaker, it is what most would consider the back wall. The Rear Wall Bounce is what most audiophiles call the front wall reflection, hence why it declines rapidly at high frequencies due to the directional nature of the speaker at higher frequencies. The rear wall bounces is the spatially average horizontal responses at ± 90°, ± 100°, ± 110°, ± 120°, ± 130°, ± 140°, ± 150°, ± 160°, ± 170°, 180°.

 

Due to precedence effect, the on-axis sound, and not the reflections rule predominantly what you hear. And this is naturally not impacted by the room (above transition frequencies). What reflection there is, gets attenuated due to much longer path length of that front wall.

This is of course correct.

Also correct is that the early reflection graphs are spatially averaged over a large number of angles and hence both masks acoustic interference, both constructive and destructive and provides no weighting for angles that may be more or less relevant in a given room, speaker position, listener environment which can impact acoustic interference as well as timing and intensity as it relates to early arrival reflections that may interference with the precedence of the direct sound.

A case in point is the room response curve you posted which has clear boundary interference, however, that would not show in a 2034 report. Nevertheless it occurs, it is audible, and it can be addressed.

The second issue not readily evident in the room response though there are some indications is the strong reflections from the very close side walls that will arrive both close in time and relatively high in power compared to the direct response. Yes it is correct that your speakers are well designed with smooth off axis response hence this won’t cause any weird tonal issues making assumptions about your wall materials, but back to the precedence effect, it will affect imaging, and while side wall reflections can make the image seem more expansive and the result pleasurable, when the wall is that close the result is invariably negative. You may not trust audiophile listening reports, but in similar situations, almost without exception where an audiophile was required to place their speakers near side walls, the addition of appropriate acoustic panels resulted in a significant perceived improvement. Anecdotally, you will not find a large professional studio with speakers placed that close to a side wall without use of acoustic treatments.

I won’t say it is universal, but it is almost universal that treatment of first reflections in a small rooms is recommended by professionals. Unfortunately, there has not been extensive research on this topic to draw on and what does exist is mainly around speech intelligibility, however, Brett Leonard in his PhD dissertation did some excellent work showing effects of a rather early intense reflections on perception and even the variability of that perception across music genres. Your position does not appear to be based on the fundamental science, available research, or professional recommendation.

britamerican
52 posts
 

Quick, tell me what frequencies in this graph are room modes, and which are boundary issues?

The mere question indicates you don’t know what you are looking at. Hint: look at the measurement again. It says right there.

 

Oh really now. You mean this graph? I know exactly what it is showing. Do you? There are clear room modes in the response. There are clear boundary effects in the response (and not low frequency reinforcement which can be corrected). Do you know which is which? Can room correction fix this? No. Can acoustic panels fix this? Absolutely.

 

The graph below shows that the total number who preferred absorption or diffusion exceeded the number who preferred reflective. The only other conclusion is those that preferred reflective used a higher volume. After adaptation (3rd trial) the diffuse group referenced to a lower volume and worked faster than the other two groups.

 

Here is the thing, though, referencing this paper was a bit of a intentional trap. The only condition in that paper that applies to your side wall situation well is the baseline. The relative path distance of your first reflection off the side wall (at least on left) is probably at best 2 msec (and looks like less) and those speakers have wide dispersion. I do commend you on using different left/right toe-in to balance the sides, made possible by a speaker with good dispersion.

The majority of the Brad thesis looks at a much different scenario, where "first" reflections are 4 and 8 msec, not to mention large reflections from both left and right speaker from the safe reflecting surface. Those times are more indicative of speakers far from a side wall and also would never occur in a home environment. The primarily lateral reflections would also not be a case for a home environment and would behave differently upon interaction with torso/head/pinna. This is the problem when trying to apply the result of experiments with drastically different conditions. The results of the experiments indicate the potential for preference in a more reflective environment when the first reflections are larger in time, but given the primarily lateral reflections, even that conclusion is suspect. You know, science.

I know you are a fan of Toole. Most of us are. Review specifically what he said,

Chapter 6 shows that in normal rooms the first lateral reflections in rectangular rooms of normal listening and control room dimensions are above the threshold of audibility. They can be heard, but are below the threshold at which the precedence effect breaks down, so there is still a single localized image. They fall into a region where there are varying amounts of "image shift" - the image is either perceived to move slightly or to be stretched slightly in the direction of the reflection. I, and others, spent hours in anechoic chamber simulations of direct and reflected sounds and can confidently state that the effects, while audible in direct A vs. B comparisons, are rather subtle. Was it ever unpleasant? No, the apparent size and/or location of the sound image was just slightly changed. The effect was smaller than tilting the head a small distance left or right of precise stereo center. The dramatic change happened when the precedence effect broke down and two images were perceived – that was a problem. The strength and spectrum of any reflection depends on the strength and spectrum of the sound radiated in that specific direction by the loudspeaker, and by the frequency-dependent acoustical performance of the reflecting surface

I could quote more and reference his book, but in summary, nothing is perfect, use what you want (at first lateral reflection). That use what you want is critical, as not all listeners, or even audiophiles listen with the same goals and may not even listen with the same goals all the time. In a music space targeted at casual listening or for the more casual listeners in the household, a space with more side wall reflections has a high likelihood of being preferred. For those who are into critical listening, muting the sidewall reflections can sharpen perceived imaging leading to a higher preference. Are you a casual or critical listener Amir?

In terms of throwing out those "professionals", I would have to throw you out as well for your insistence on only your way when your luminaries don’t even say what you claim.

What is unfortunate is I agree with you far more often than not, but you like so many here let your ego get the better of you and you let that drive a need to be right to the point that you make poor use of the available science, drawing conclusions that are beyond what the science is able to reliably claim.

Toole (with others) did do testing on reflections, but even those had limited scope, and they were done in anechoic conditions which may have either amplified the effect or muted it. I personally would lean towards the former, but I can only lean, not state, as the data is not there.

One thing is clear, there are not volumes of research on this very specific topic of acoustic panels of diverse properties with the diverse speakers, or even on speakers with good dispersion properties, in listening rooms of diverse proportions. There is some research, sometimes somewhat related, the rare bit closely related and some that is only loosely related.

 

See the title? "Estimated in-room response" which we formally call PIR (Predicted In-Room Response). This can even be used to predict listener preference although the formula can misfire.


- This is the steady state response

- This is a spatially average response, not the response at a particular spot, in a particular room, with a particular set of speakers, placed in a particular spot, and with the listener at a particular spot.

 

Bottom line, don't go slapping mattresses all of your everyday room.  It is not necessary and will uglify your room and likely not have the effect you think it will have. 

Bottom line few are recommending that. As well, carpets only treat the floor and are narrow in absorption no matter how thick

 

britamerican
52 posts
 

No.  The graph cannot be used to determine modal response or SBR.  It is absolutely the wrong presentation for that use.  Again, it says so right on the graph what it is for.  I only post it because that is the shot you were seeing on the computer monitor, not because it is suitable for the purpose you are asking about.

The graph on its own cannot, but we also know the speakers and with enough accuracy the speaker placement as I noted we had your system image. Look at that graph, now go do a bunch of measurements on your speakers and their relationships to the walls and your room dimensions, calculate 1/2 and 1/4 wavelengths then start relating multiples of those numbers to your graphs. Science, not conjecture.

 

britamerican
52 posts
 

Nothing transformed my audio system and ideas more than that processor.  My jaw fell on the floor in the way it seemingly removed the walls from my listening room!

What kind of subjective audio-foolery statement is that?

Does that say more about the processor or more about your room?

britamerican
52 posts
 

@mapman easy to slay when many just act in bad faith.

@prof , your arguments are mainly sound, but one of Feynman’s points you keep referencing, The first principle is that you must not fool yourself, also applied to Amir.

Amir keeps quoting that there is extensive research showing reflection and no treatment other than regular furniture is not only good enough, but that it is superior for home listening. This is not true. There is very little research specific to home listening and room treatment across a range of other variables including what treatments, what speakers, etc. There is some modestly direct research with limited variable adjustment and limited listening panel. There is some anechoic work on specific properties. There is adjacent but not direct research that cannot be directly applied unless the conditions are similar.

As I noted above, that research indicates that specific application can result in specific improvements that can be interpreted as technically superior, even if not as preferred. A bit of cognitive dissonance to insist on electrical purity (absent evidence to prove preference across use cases and type of deviation) while accepting subjectively superior based on what is limited direct research and use cases.

That is furthered with the straw-man argument about mattresses all over the walls and other hyperboles about acoustic treatment as if the only binary options are no treatments and bad treatment. That is further illustration of bias.

I made the point of the Lyngdorf graph and system photos together indicating boundary issues which was casually dismissed though clearly there to someone who has experience with room measurements and the causes. This is something that can be addressed with specific implementations. Not stapling mattresses to the wall.

As concluded by Toole and others (not so much specifically researched), controlled lateral reflections can be better or worse, depending on the person, music, use case, etc. While anecdotal experience is not research, there is strong indications from professionals not prone to hyperbole that dynamic monopole speakers close to the side walls will produce a result that many audiophiles, including those who prefer critical listening, will likely not prefer and that this can be addressed with acoustics.

Even hyperbole about massive amounts of velocity absorbers will not fix deep bass in a small room while correct, is not helpful, as no acoustic professional would even attempt that (nor would most audiophiles) as they are well aware it will not. They will use other products and means to reduce the peaks and valleys of room modes and may or may not include room correction, though professionals would almost as a rule recommend it as it not only corrects level issues but can assist in time (reverb) issues depending on implementation.

There are enough misconceptions in audio based on either no science or limited science. I don’t think we need any new ones.

 

It was what led to Room EQ eventually becoming standard in every AV processor or Receiver you buy today. 

This is probably hyperbole. It was a great product for its time, but pioneering work at B&W is probably what kick started room correction.

britamerican
52 posts
 

Amir keeps quoting that there is extensive research showing reflection and no treatment other than regular furniture is not only good enough, but that it is superior for home listening. 

We have hardly discussed room acoustics so the claim that I "keep quoting" research is obviously wrong on the face of it.  The other bit is what you are manufacturing on my behalf and then complaining about.  Really, the plot is lost.

 

Whether I paraphrase what you said or waste time quoting you absolutely have referenced research or existence of (without quoting), and used that to promote a particular view that is very much due to variability subjective.

 

 

 

We got here because someone claimed I must not have good enough equipment to hear the difference between cables. 

Since you are responded to me, at least initially, we did not get here that way. You made claims about rooms and acoustics that were inaccurate.

 

And that the focus must be to deal with the modal response first and foremost as that is a constant in every room. 

Why do you have your speakers far out from the front wall (front from an audiophile perspective, not 2034). Was that modal, or to minimize boundary issues?   Are those boundary issues gone completely, the ones that DSP cannot correct?

 

Importantly, I made no statement about superiority of furnishings relative to acoustic products. 

Paraphrasing because I don't feel like going back and cutting and pasting, but pretty much yes, you did state that furnishing and natural reflection was superior, though your responses had an air of arrogance as you later made the assumption the acoustic implementation would be haphazard at best. I will state at this point, that unlike some other audiophile additions which likely are inaudible, a couple acoustic panels will make a readily audible and measurable change. While controlled listening would be preferred, it would be near impossible in this case, hence accepting preference ratings is valid. That is furthered by the reports of many who would less susceptible to expectation bias. The result is not always positive.

 

I quoted from the very research you put forward that it had nothing to do with listening for enjoyment but that it was a test of recording/mix engineer productivity.  And even there, a reflective sidewall as preferred by majority so quoting that was totally inappropriate and wrong.

Therein was a bit of an intentional trap. For one, the majority did not prefer the reflective sidewall. Go read it again. The sum of the diffuse and absorption preferences exceeded the reflective wall. As I previous noted, the conditions in this test were not at all like what would be experienced in your room or probably any typical listening room. The trap is that research like this is used to make conclusions that cannot be made due to vastly different usage conditions. The only part of that test that was like sidewall reflections in your setup was the baseline.  Trap are effective at illustrating bias formed through incorrect usage of information.

 

3. The path of treating all reflections with absorption will inevitably lead to people slapping absorbers over every surface they can find.  After all, if a little bit is good, a lot is better. Soon the room is deader than the steak on your plate, sounds lifeless and the room ugly as heck.

This is very rare in practice and would go against most recommendations from acoustic professionals and most of the audiophile community who recommend absorption and diffusion, being careful not to over deaden a room, that preference plays a large part in what is done, and hence accept you may or may not like the results and will have to adjust.

 

Bottom like, get speakers that are well designed, do some EQ for low frequencies where acoustic products have little prayer of fixing issues there

You should probably qualify low frequencies. However, as noted by Mahgister, Helmholz resonators work at low frequencies and while narrow band, that can be good. So can diaphragmatic absorbers. So can multiple subwoofers. EQ is absolutely beneficial, but effectiveness is localized and EQ will work even better if acoustic methods are used first.

 

And certainly don't let them shame you into throwing blankets on the wall or else your system sounds like "crap." 

Would this be akin to someone shaming someone buying, owning, and using an amplifier that has poor distortion measurements, highly likely to be audible, even though they prefer the outcome?

 

Mainly what I see is audiophiles, from their own experience, and that of acoustic professionals, is that they have added a limited number of panels to fix a perceived problem, usually caused by limited space, and that the majority have been happy with the results. That is not to say there is over use of panels in some particular ways, but those are likely not doing harm, they are just not doing anything.

 

There is more to audio life than proving 1+1 = 2. You have that part down pat. Think harder problems.

britamerican
52 posts
 

@amir_asr 

 

I hope you will take this to heart what I am going to write here, and why your approach is too dogmatic and hence stuck with no potential to move forward.

Last night you argued vehemently that reflections in a room MUST be better, that it MUST essentially be more pleasant, but, using the research that allowed you to reach that conclusion, you must also accept there is reduced clarity of the image (as the research indicates) and that at least for first lateral reflections there is no right answer for all rooms and all people.

Stated another way, you vehemently argued that a less accurate approach would absolutely result in a better listening experience, to the point of claiming that anyone who suggested doing otherwise was incompetent. Your words, not mine. Paraphrased but still your words.

Today, you posted this:

The Mola Mola Tambaqui DAC shows again that just because a DAC is designed from ground up, it need not perform poorly. It is actually the opposite with it performing at the top of the class with respect to distortion and noise.

Effectively you are stating that the only correct way to design a DAC (or any piece of electronics really) is for it to perfectly reproduce / amplify a signal. Do you not see the issue?  On one issue you are advocating, literally insisting on a provably inferior technical solution, while on another issue, you are insisting the only correct way is a perfect technical solution, and you leave absolutely no room, except at best cursory, that a non-perfect solution could be more pleasant. It is a irreconcilable position.

I understand what has likely lead to this point in time. Both scurrilous marketing coupled with a group of audiophiles insisting that equipment has properties beyond the understanding of science. You know that is not the case. I know that is not the case. Many know that is not the case. So what is the possible benefit of measuring yet another DAC, or now yet another amplifier that performs well beyond any ability of humans to detect the faults?  There is not. It does nothing to advance the science or art beyond identifying new price points. That is at best consumer protection, not science. Ditto for exercises in debunking product claims. While valid it is not science, it is consumer protection.

 

So I will challenge you. Turn the ship. Stop proving 1+1 = 2. Use your reach and platform to do something useful for the industry, both for your followers and detractors, and put effort into understanding or debunking as the case may be, the audibility, and audible impact, negative or positive of less than perfect signal construction and amplification. Just like that those less than technically perfect reflections can create a superior experience, it is possible that less than perfect on the electrical side can do the same. It is already done on the music creation side for improved preference so the evidence is there to support it conceptually (even if not on all music).

Are you up to the challenge?

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