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

@amir_asr so room treatments do nothing? All of the producers and sound engineers who record with them to create less issues and surrounding booths with it so the vocals are clean don’t know what they are doing?? You can hear the difference. It’s night a day.

No, room treatments do something. Just not what you think.  This idea of copying what "pros" do in the process of creating music is why we are in such a mess.  They forget the fallacy of appealing to authority and jump right in both feet.

You are taking it even a step further.  What a single microphone picks up in a tiny vocal booth has absolutely nothing with you sitting back to listen to music in a much larger space with two ears and a brain.  I am not a recording engineer but I imagine they want a dry recording of that vocal as to then embellish it with as much reverb in post as they need. That has nothing to do with what we do in our listening spaces.

There is this assumption also that if pros do something, it must be right.  A pro creating music has expertise in that field, not in science of acoustics.  They haven't gone to school to learn acoustics, not have they read massive body of literature on effects of reflections in room.  They hire joe acoustician which does what the poster said above: "we need to treat the room" or at least the front if in the form of LEDE or "Environmental Room."  Acoustic products are put all of the walls making the room look special.  This impresses the client resulting in higher billing per hour.

To be sure, at high level, an empty room is too live to be usable for enjoyable of a lot of music.  In that case, if you have a dedicated room like that, you do need to "treat" it.  That can be with acoustic products or in my case, ordinary furnishings that perform a similar job, are not ugly and often are much cheaper.

The research I post above shows that even when it comes to getting work done (recording/mixing), the notion that an absorptive room is right was shown to be false.  People in that space would do well to rethink what they are doing.

All of this was extensively discussed in the thread I linked to.  There is no point you can bring up that was not addressed there with volumes of research, not opinion based on stuff you have read online.  This is what we do at ASR.  We discuss the science contrary to people who think we only "measure."

BTW, if you were listening to that singer, there is a good chance you would want no absorption in that booth.  This hits on the proverbial person's voice sounding best in a shower!

You literally use a tool that mimics an anechoic chamber. You really have your head up your rear end. 

The tool is designed to characterize a speaker independent of the space it is placed in.  Otherwise, its measurements will be specific to that location so not transportable to others.  Research shows that we can use the anechoic measurements of frequency response in 3-D space, combine that with statistical mean of reflections in a number of listening rooms, and predict, with high accuracy, what happens in such a room (above transition frequencies).  I post this already:

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.

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.  Your "aunt's" furniture will do just fine in providing some diffusion and carpets and such (if thick) provide good bit of absorption.  Just get it to the point where talking in there is comfortable and you are golden (if you like, you can measure using RT60 and get in the range of 0.25 to 0.6 second for typical small room).

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

 

The snake in snakeoil bit you in the butt.  Wonder what kind of reception the above statements would receive over at ASR?

Snake oil?  No way.  Benefits of Room EQ is proven conclusively.  There is no snake oil involved.  Performing this across 8 channel 20 years ago was expensive.  Fortunately it is not today.   Here is a nice paper to read on power of EQ in fixing room response:

Three systems beat no EQ (dashed black) in controlled listening tests.  Notice the peaking in bass response of the no-EQ system.  If you care about high fidelity and you have that in your room, I don't know what to tell you.  You can get variations as much as 25 dB in bass without equalization!

Above is not a surprise by any regular menbers and readers at ASR as many deploy EQ just the same.  Yes, it took some explaining and repeating for even our crowd there to get it but it is the consensus view.

Bottom line: the first step in creating any performant audio system is to figure out how you are going to perform equalization. 

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.

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.

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.