Acoustic treatment for my living room - Page 19

ignorance preserved. an anechoic speaker-listener response means exactly what it says: the speaker to listener response is anechoic and there is no indirect signals (generated from the speaker) that impede the listening position. the direct signal from the speaker is all that is heard at the listening position with no contributions from the room. eg, absolute accuracy of the direct signal (no room masking with respect to intelligibility, localization, imaging, or frequency response anomolies due to superposition of direct + indirect signals). the direct signal is all that is processed.

however, the epiphany you'll have (if you ever manage to comprehend the copy-paste commentary you're presenting) --- is that an anechoic speaker-listener response DOES NOT INDICATE the ROOM is an anechoic chamber - as you continually attempt to present!

some here seem to be completely oblivious to what "perspective" means; eg, speaker-listener response vs listener-room response.

so, the speaker-listener response in an NE room is indeed anechoic. but the reflective front wall and floor mean that the listener is NOT in an anechoic room as his discussion and actions within the room are reflected back by the reflective front wall and floor - such that the user is NOT uncomfortable as one generally is in an anechoic chamber. while he still MAINTAINS an anechoic speaker-listener response!!





yep - an anechoic chamber is not a pleasant space to mix music or enjoy - but an NE room (or equivilant design) has an anechoic speaker-listener response while NOT being an anechoic chamber.

oops! such fundamental mistakes with regards to vocabulary...something that happens easily when the user has zero real world experience with respect to the topic and instead relies on google, AES search field, etc.




for the record, amir (who has zero experience in the recording world) - is attempting to discredit Hidley/Newell and the NER design. he, who wasn't even aware of what NER was until he googled it, is attempting to call NER "flavor of the day". now that's bold.



solidiying your complete lack of experience, understanding, and knowledge on the subject. what on earth do you think the mixing board/desk blocks? could it be the floor reflection?




are you attempting to discredit Hidley with your statements?

what experience do YOU have in control rooms - what types of control rooms have you been in, worked in, etc?

or are you all copy-paste parroting with no real world experience?



so the mixing engineer has a choice in what they want, but the people who just want to enjoy music do not?

even toole says "it is a matter of taste",

How low and how do you know this?

Can you just answer this in "former" or "latter" term? Is reference undefined or it is defined but it is too often just plain garbage?

http://lmgtfy.com/?q=vocal+frequency+range


The "reference" (as a singular definition) is undefined because there are a myriad of references, depending on the artistic intention and the system the artist used to sign off on that intention. In addition, the "reference" might be of poor quality, or subjectively unpleasant. These are not contradictory statements.

And what did it have to do with my reply to amirm, "To deal with vocal frequency range, shallower absorbers can do the job so it doesn't have to be recorded in an anechoic chamber looks like that."?

Post #516, I replied, "Undefined..., which means there's no way to tell what is or isn't reference sound."
Post #517, you replied, "Thats not what undefined means."
Post #518, I asked you, "But what I'm wondering was, how did you become aware of this and how long did it take?" and some more questions which you didn't reply.

Then post #527, you claimed that you think you have explained your position. Whatever that "position" may be is unclear however, you didn't respond to post #518.

So, you've switched the subject from "reference" to "recording" and now back to "reference"? Did you say something about moving target?

history is fun -

Thanks for the response. I noted the same said differently in your other forum post. The issue is not what you have said, but the accuracy of your statement relative to response being anechoic even though clearly reflections are allowed in Non-envrionmental rooms and contribute to listener pleasure/comfort. If they are there for our ears to hear and perceive, surely they exist for a measurement tool to see them too. And hence, the reflections are above noise floor of the room and not anechoic.


I am going by your language. The industry term anechoic is very specific: absence of echo. The term you are using, "anechoic speaker-listener response" is not used by others perhaps for good reasons: it is not correct use of the term.


You seem to be saying there are two parallel universes for me as the listener sitting in that room. There cannot be. If I am there and I hear reflections due to those reflective surfaces, then there is no such thing as anechoic response. The sound arriving at my ear is a combination of direct sound of the speaker plus reflections from other surfaces. Ergo, nothing is anechoic. Echos exist.


Nope, it is not "anechoic." It is approximately so. They have dialed back from anechoic enough to make the room pleasing yet satisfying their goal of hearing direct sound of the speaker. Instead of having all the surfaces blocking sound, they leave some to reflect. Nothing more complicated than that. There is clear admission here that psychoacoustics plays an important and non-intuitive role here.


But it is flavor of the day. Had you not moved to crown Blackbird studio? How similar are those rooms? One with 4 foot diffusion everywhere and the other with mostly absorbing room? How are they not flavors of the day? Folks are experimenting. Tell me when they are done with subjective listeners who buy that music and then we can see if we should follow their lead. Otherwise, despite their qualifications in recording music, I do not follow their path in design of home listening environments. I listen to people have researched what surface should be reflective and not a choice like the floor, or the back wall, or this other wall.


Thanks for the larger letters. My eyesight is not where it used to be.

So now there is a pathway from the speaker and it is "blocked" by the mixing board/desk? What blocks the reflections from the surface those instruments? And if a desk/mixing console is necessary, how is that possibly relevant to a home situation?

Let's hit the literature a bit. AES Paper: A Proposal for a More Perceptually Uniform Control Room for Stereophonic Music Recording Studios, by Newell, Philip R.; Holland, Keith R. (1997):

"Except for the floor, and any equipment placed within the room, the monitors face something approximating to an anechoic chamber. "

So first of all, your statement of "anechoic speaker-listener response" is invalidated. The speaker clearly sees the floor and equipment as reflective and hence nothing is "anechoic." The article goes on:

"From the monitoring direction, the reflexion problems from recording equipment can be dealt with by angling the equipment such that reflexions pass away from the listener and into an absorbent surface. If this cannot be done directly, then the offending surface can be protected, either by anabsorbent shield, or by a streamlining devices that will deflect the incident waves around or away from the object, and prevent them from, in particular, returning to the front, reflective wall and thence back to the listener."

Seems like fair bit of countermeasures are being put in place to deal with reflections. Clearly not anechoic. And clearly the equipment blocking the floor reflections wasn't enough to render it such.

We can document this quantitatively as the paper above shows impulse response of the room:

We see that the room is ringing up to 50 msec and past. Last time we discussed accuracy, you put this extract of the image I post earlier from you:


Clearly the two graphs do not match. One is true Anechoic with an impluse and nothing following it, and the other, having ringing past that. They also post the frequency response:



I see 10 dB variations above the transition frequency, and that is dismissing that dip that they say was a crossover problem. If this room is anechoic, and that speaker has such wild anechoic response, it should not be something you spend money on.


I don't talk about people but the topic. And the topic is the one you put forward: a fantastical notion of a room that is not anechoic but somehow is. You used the room style he developed as proof point. Research tells us that if you are going to use reflections to good use, the floor is not it. That he would come up with that as the solution means his work in this area is not instructive for what we like as consumers in our homes. New research has invalided his approach as being the valid one. But maybe you show me half a dozen home room acoustic experts that advise leaving the floor reflective and blocking them with tables....


What experience do I need to find the definition of the NE Room? Isn't it as the research says it is? It is not like you have provided your own personal data, designs, research references. So what I have, is the best thing in front of us .


Everyone has a choice. Please don't keep posting this slogan. What people are searching for in these posts, are best practices. We have discussed Dr. Toole's. You don't seem to like that. Now we are discussing your best practices as coined in that phrase. You gave the example of NE Room as such. We dug in, realized that your understanding that it is somehow is anechoic is not right. No one in the industry uses your phrase and data shows that the room clearly deviates from an anechoic response. And that aside, the model came out years before research showed us what consumers prefer.


This is what he says at the start of that paper: http://www.harmanaudio.com/all_about...ience.pdfAudio

"Audio products must sound good. That is a given. However, the determination of what constitutes good sound is a matter that has been controversial. Some assert that it is a matter of personal taste, that our opinions of sound quality are as variable as our tastes in wine, persons or song. This would place audio manufacturers in the category of artists, trying to appeal to a varying public taste. Others, like the author, take a more pragmatic view, namely that artistry is the domain of the instrument makers and musicians and that it is the role of audio devices to capture, store and reproduce their art with as much accuracy as technology allows. "

:lol:

he still doesn't get what speaker-listener response means and how a signal generated from the speaker is measured anechoic at the listening position, while the room in itself is not an anechoic chamber.

his article quotes even invalidate his own commentary...

how grand such a display of perpetual ignorance! ah, to be an overnight expert on something you were only made aware of its existence a few hours prior...

here - im going to re-use his quotes to restate what i've already stated for anyone who may be confused,


so before modification, the floor and equipment are the only objects or surfaces in the room that reflect indirect energy to the listening position. but do they leave it as is or do they address the floor and equipment? let's find out -


so now, no indirect energy generated from the speaker impedes the listening position! anechoic speaker-listener response! direct signal is the only signal processed! how grand a concept!
--- while still maintaining a reflective front wall and floor such that the LISTENER does not feel like they are in a completely dead/anechoic room (which may not be comfortable to work in for extended periods of time).

this is such a simple concept!!! oh, but apparently he also has issues with what speakers were available in 1982 - im curious to know what he was using back then?



for the 4th time (!!!!) - blackbird is a SURROUND SOUND control room! not a 2channel like NER/LEDE/RFZ. how popular was surround sound in 1982?

is he ever going to address his ignorant commentary regarding singers and the environments they apparently don't like to sing in? is he going to invalidate vocal booths of which have been a staple in recording studios or home studios for decades? is he finally going to show us how the rt60 (NOT the ETC) is the tool for the job for identifying how much and where to apply treatment?

"You seem to be saying there are two parallel universes for me as the listener sitting in that room. There cannot be. "

nope! no fancy voodoo universe magic going on here! just simple perspective.
two scenarios. two perspectives.

in scenario 1, the speaker is the source. it generates a signal and the only signal processed at the receiver (listening position), is the direct signal. all other indirect signals are attenuated (absorbed/redirected). the speaker sees an anechoic room with respect to receiver (listening) position. none of the speaker's indirect signals (first-order reflection, 2nd order, etc) will impede the listening position. it is an anechoic response as the direct signal is the only signal processed when the loudspeaker is the source and the listening position is the receiver. this is the speaker-listener response.

in scenario 2, the engineer at the listening position is now the source. so, as he communicates to other humans in the room working on the task at hand, reflections from the floor, front wall, equipment, etc - reflect back into the room such that there is a sense of "environment". as such, to the engineer, it does not feel uncomfortable like if he were in an anechoic chamber.

speaker-listener response vs listener-room response. not parallel universes, just difference perspectives on response.

i hope that clears things up for you, amir. i know you're struggling with the basic concept of different perspectives and relativity. this confusion of not being able to understand the view from another perspective is probably also why you're having such a hard time comprehending the time-domain and what the ETC provides. tunnel vision =

You asked me how low and how do I know it - that was the answer.

If you ask me why it is relevant, I ask you - how can a shallower absorber "do the job" if the job requires dealing with the vocal frequency range which ranges below 100Hz?


No "switching" - both statements are true. The reference can be garbage if, for example, the mixing engineer is not competent, or the mixing room has gross deficiencies. The recording can be garbage if, for example, its horribly over compressed or the volume is way too hot.

I admitted above that the latter is not a room acoustical issue and so is perhaps not relevant to this discussion. It is, however, absolutely true.

Are you still confused? I don't know if I have the patience to explain myself yet another time....

A room with partial coverage of thin foam on its walls does not achieve reflection-free status even for voice. But I am happy to be convinced with measurements. Do you have any?

Meanwhile, let's make sure the plot is not lost. This is what I said which Arny responded to: "How many singers do you know that like to sing outside where there are almost no reflections? Have you tried to sing yourself there? Fact is that some of these effects are totally non-intuitive. We think a reflection is a bad thing. But clearly no singer thinks that. I know it is hard to let go of these notions but let go we must."

Showing me where they are recorded for final release after processing is not the answer to that. Here are a random set of pictures from the listening booths on google search that have people in them:








Notice something? They have headphones on. They are not hearing the room they are in. As I said, a dry recording is being made for later mixing and processing.

I have been in anechoic chambers. I assure you, a reflection-free place is not where you want to sing. On the other hand, I am pretty sure if I were put in a tiny box/vocal booth with no treatment, I would not like that either. So folks treat them to get them down to an acceptable level for recording ("tracking" to make Local happy ), and then process it later to make it something the talent likes.

first, acoustic treatment and now vocal booths. you realize you have a habit of finding improper ways of deploying the vary thing you're attempting to discredit?

re: LF absorbers, you chose a thread where someone poorly applies LF porous absorbers (no where near large enough / surface area coverage to be effective). yet you presented this as global statement that porous LF absorbers are not effective - "see! no frequency response change!"

now, you choose some poorly designed vocal setups (some even made me chuckle) - as some sort of global statement regarding vocal booths. vs what's done right.

it's poor deception at best. step your game up.

oh, and they use headphones so the background track doesn't get picked up in the microphone they're singing into and also so they don't get off-pace with respect to the rest of the instruments (you know, the track theyre singing over??)

Thanks again for explanation. You did not address the measurements I provided though. Fact remains that the listener is not just hearing the direct sound. So if they indeed meant to create an anechoic path, they failed at that. If you don't believe that data set, here is another from the multi-channel implementation of said room style:



So once again, the impulse response is not anechoic even though this room has partially non-absorbent floor. And the frequency response pretty poor for anechoic chamber measurements.

Here is some relevant text:

"Early reflections are defined in the recommendations as
those that arrive during a time interval up to 15 ms after
the direct sound, and should be attenuated by more than
10 dB in the 1-8 kHz range. In our case, the impulse
responses from loudspeakers L (left), R (right) and C
(centre) show early reflections which are attenuated by
far more than the 10 dB suggested by the standards.
This attenuation is due to the highly absorbent
properties of the rear and side walls and ceiling, which
are also responsible for the adequate behaviour of the
reverberation tail. For this measurement, the floor area
between the front wall and the listening area has been
covered by foam mats, because otherwise the floor
reflection would impede the fulfilment of the early
reflections requirement. Note that, at 1 kHz, there is a
significant sound radiation towards the floor, that is
about 40º off axis. At this frequency, that coincides with
the frequency of the crossover, the radiation towards the
floor is only around 3 dB below axial output for the
woofer, according to the manufacturer data, and less
than 5 dB for the tweeter, regarding the horn directivity
characteristic [8]. The thickness of the mats, 8,5 cm,
was chosen to provide a reasonable absorption above
1kHz. Note that 8,5 cm is approximately one-fourth
wavelength at 1 kHz, which means that the absorbent is
still present at the distance to the floor where the particle
velocity has a maximum. "

So clearly this is not a room model which achieves anechoic response. For sure it is an attempt at highly attenuating reflections of any sort. But anechoic response is something else. Use of it here is an exaggeration, not statement of fact backed by measurements. As soon as you allow reflective surfaces, as the line in the movie Jurassic Park went, "life [sound] finds a way" to bounce around there. Even your body act as a reflector. So do the backs of the equipment, the chair, etc.

So much was said in the article: ""Except for the floor, and any equipment placed within the room, the monitors face something approximating to an anechoic chamber. "

Approximating something is not the same as it being that way even if one excludes the other major contributors to reflections as the author did.


Understood. Thank you for clarification. Wish you had provided that when the question was asked of you the first time . That aside, we are not working in our rooms so that is not a consideration for music enjoyment at home. For us, research that shows that we like reflections and that they improve intelligibility and enjoyment of music overcomes any intuition we might have in taking them away when designing recording studios.


On it being a struggle, it is sometimes with your posts. Not because I can't follow the technical topic. I certainly can. But because you had coined a term here that even the people who had designed the room had not used. Nor had anyone else that I could find. You provide no measurements to prove your point. Nor any references to papers to read. So it ends up being how loud you can shout that you are right.

As to ETC, that is a losing proposition for you in this case. After all, they did not start with an empty room, ran ETC and then proceeded to treat the reflections as you mandate. The threw out the tool and padded the whole room! Clearly they had no use for any analysis in that regard. What did I say about your posts being difficult to parse . Your prime example scenario calls for blind treatment of almost the entire room sans the floor and front wall, going against every accepted practice for design of home listening space.

That's right. So the example should have never been put forward to prove singers like their voice in there. It was an orthogonal example to the topic being discussed.

My reply to amirm was, "To deal with vocal frequency range, shallower absorbers can do the job so it doesn't have to be recorded in an anechoic chamber looks like that." What relevance does your reply have? The term"shallower absorbers", what did you think it meant that made you want to reply with "Vocal range can be <100Hz!", especially with exclamation point?


I was asking you about "reference" sound quality but all of a sudden, out of blue, you bring up "recording" sound quality, which by the way are two different things. Why?

You said "reference" is undefined and yet made a claim about "reference" sound quality. I pointed out that you can't have both. You either don't get it or don't want to admit your own contradiction to yourself. How can you evaluate "reference" sound when you don't know if it's "reference" or not?

and a surround sound implementation of NE is relevant to this conversation how? just because someone made an attempt to fit such a design into surround sound --- that's not what the original implementation of NE was for (which was 2ch stereo). blackbird C, as discussed, is one particular example of a control room model that is suited for surround sound. LEDE/RFZ are 2ch stereo models also - and unlike NE (which is anechoic speaker-listener response), LEDE/RFZ allow ample time for the brain to digest the direct signal (ISD-gap; the effectively anechoic time period) - before terminating (sharply delineating) via a laterally arriving (think about that! laterally arriving!) dense, exponentially decaying diffused soundfield. so you hear the direct signal which is accurate with respect to localization and imaging within the haas interval, and then for a sense of space to the room, specular energy then impedes the listening position in a diffused manner, laterally arriving for a sense of spaciousness.

that's the primary foundation for those concepts. each has their own approach. and different engineers like working in different types of environments, just like there are subjective preferences for home listening. BUT, the point is - they are Concepts of which the criteria (response) can be emulated and repeated! such that an engineer who is used to working in one NE room can then work in another room and should feel right at home with respect to his workflow.



hmm, it's too bad we don't have a measurement tool for such a scenario; to determine whether indirect specular energy is impeding the listening position via such reflections. isn't that what the ETC is for ??

if you see a high-gain spike on the ETC, you know the time arrival. working backwards via the (speed of sound * time arrival), you know the total flight path. then you can work backwards to identify which boundary the indirect reflection is from and treat it as required - then remeasure to verify it is attenuated.



i went over it at least three times in the "Freq vs Time" thread - your commentary there in response was thus, unwarranted (as it was here since clearly the misunderstanding was on you) -- but at least you hopefully you understand what i imply when i say "perspective".


that "accuracy vs realism" graph was MORE than sufficient to get the point across (now i think you understand why i presented it) based on speaker-listener response as measured at the receiver (listening position). it is not to be taken literally, but is a statement of concept. placing a mic on the floor is not going to magically turn any speaker into one with a flat response --- it's a statement of concept that since the direct signal is all that is processed with respect to speaker-listener response, then the frequency response will be the response of the speaker in an anechoic chamber (no indirect signals causing constructive/destructive interference).


are you implying there is no "planning" stage of a multi-million dollar control room design? and today, there are plenty of modeling software tools available that can do the bulk of the work (http://www.afmg.eu/index.php/products.html) -- but these become less and less relevant when dealing with small acoustical spaces. the ETC is the tool for the job, used to measure the ACTUAL acoustical behavior (specular region) of the room once in place --- and it is ESPECIALLY useful for identifying edge diffraction from speaker cabinets or nearby boundaries/objects, speaker alignment in time, etc. it is useful for identifying how ALL of the indirect specular energy impedes the listening position. but it is NOT an end-state goal! it is merely a measurement tool. YOU decide what the end state response is - the ETC is simply a measurement of the acoustical space with respect to the specular region. Gain vs Time of how specular energy impedes the listening position. and once you think about Time in terms of "Distance the Reflection Traveled", as time = distance (due to speed of sound), then you can visualize better what the tool is telling you.


NER was an example of an anechoic (direct signal) response while NOT being in an anechoic chamber. what's comical about your statement is it is actually ME who preaches to these guys to STOP blindly coating entire surfaces/boundaries with thin porous absorption and to only surgically place broadband absorption within the room at the ACTUAL problematic reflection points based on measurements and the response THEY wish to achieve. why do you think i recommend the ETC measuring tool so much? - for ACTUAL identification not BLIND guesswork with a mirror. and providing such a tool for the job does NOT mean that i am blindly RECOMMENDING that ALL USERS make the decision to absorb such reflections.

but it doesn't matter as those guys will do what they want anyways or what the 'herd mentality' is - go take a look at the dedicated home theater sub-forum and see how many people are literally jumping at the opportunity to completely damp their room with absorption!!! and worst of all, they apply THIN absorption which merely attenuates the mid-HF band and allows the lower specular region energy to persist! coloring the reflections! exactly what's stated NOT to do if a user decides they prefer the reflections absorbed!


whether one is working in an accurate listening space or listening to music in an accurate listening space makes no difference! it's the user's choice! some people want a critically accurate listening space such that even poor recordings (or bad masterings) are OBVIOUS -- even if they are NOT pleasurable! other people may want a room of which may not be as accurate, but maybe makes all types of music sound good (and makes the defenencies in poor recordings even less obvious and thus, more pleasurable).

some car enthusiasts may want an accurate suspension geometry of that in a formula 1 car. you wouldn't drift around a corner in a formula 1 car because it is slower and thus, less performance. but - another user may think drifting around corners is more subjectively pleasing to them - so that's the route they go. it's the user's choice!

The measurement was from the front channel so the fact that it was multi-channel was immaterial there. And at any rate, you ignored the last set of measurements I showed from one of advocates of that room style which was 2-channel.


Again, the first set of measurements was from Newell for a 2-channel system.


Funny you should bring that up. Because when I went searching for that phrase you use, I landed on this post about that room:

"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. 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."

Doesn't sound too complimentary to me .


I was hoping you would mention that. Let's have a show of hands. If you had a choice of "realism" or "accuracy" which would you choose?


No, I am saying the obvious: any room model that is based on a formula to treat the walls is by definition devoid of a need to run ETC to figure out what to do. So none of these room model references back your suggestions to this forum.

Ironically, Dr. Toole's method follows a similar system in that he classifies what is a good reflection relative to speaker and listener position and then provides the necessary treatment. Same is true of Keith Yates.


Or maybe it is just a waste of time. You are much better off looking at your frequency response variations which immediately tell you what is wrong. I showed that in my summary post: http://www.avsforum.com/avs-vb/showt...2#post21937322

I then suggested it to the OP in that thread and he now has an immediate course of action to improve the sound of his room. The sonar display was not remotely helpful to him, nor was able to demonstrate the massive frequency response errors.


As a concept, it was never anechoic. It cannot be with two reflecting surfaces or we would build anechoic chambers that way.

I am sorry if I missed some other point you made. I am trying to not make this a full time job any more than it already is .

quite a large sample pool you've based your conclusions room. does the mix/mastering translate well in NE room? that's the whole point, isn't it?


so you ignore the usefulness of the ETC to identify sources of edge diffraction? even from that of a speaker cabinet? or other non-obvious sources of 2nd/N-order indirect high-gain reflection?

tell me, earlier in this thread you said you wanted to absorb front and rear wall reflections. what tool do you use to verify they are attenuated?


what measurement tools are utilized for this process?
what is the process?
do you have any documentation that shows how and why they placed all those absorbers and diffusers in the harman room?

anything anyone here can emulate? the treatment-application process like the harman room?

im dying to see this 'rt60' measurement to determine what types, where, and how much treatment to place in a listening room.


did you see my editing?
http://www.avsforum.com/avs-vb/showp...&postcount=469



so tell me, he has a window at the left sidewall reflection point which breaks spectral symmetry with the right wall. what do you do?




NER is not described as an "anechoic chamber". it's a direct signal only response with no indirect room contribution. where are you seeing NE room described or advertised as being an anechoic chamber or anechoic room?

does the signal from the headphones contain room reflections, or is it direct signal only?

and they don't always wear the headphones over both ears

care to imply whether you've tracked vocals before?

How many sample points did you provide? You only provided one from George who was part of the project to create that room. In that regard, the comments have more validity from Jen. Good to know you accept them as not being complimentary .


Yes, I completely ignore it. So does Dr. Toole. What on earth are you going to do after you find out you have cabinet diffraction? Cry or take a file and start rounding the corners? As I said, buy good speakers. If you start with bad ones, you are on the wrong course already.


It is all explained in my summary post.


Fully documented by Dr. Toole in his classes, presentations and book. Same from Allan Devantier.


I have provided that reference multiple times. It even includes the answer to your question above which I have quoted here and in the other thread. here it is again. AES paper, A New Reference Listening Room For Consumer, Professional and Automotive Audio Research", Sean E. Olive (2009)


Sure. It is very easy to do. I have been in that room a number of times and it is very easy to duplicate. All is extremely well documented and logical.


I explained it in my summary post and Dr. Toole is your ultimate reference.


As I said, no. You made such wrong commentary in the first response that the rest did not merit a read. Anyone who sees those measurements and thinks that the room impact is not in low frequencies and that we must fix that first, is honestly barking at the wrong tree. While you go after figuring out the diffraction in speaker cabinets, the rest of us are after fixing 40 db frequency response variations with simple yet powerful techniques such as multiple subs, SFM, EQ, appropriate speaker selection.


Wouldn't be my first worry. I would first try to fix the bass. He is a movie guy with multi-channel sound so by your own statement, your NE, etc. room models don't apply. And I am pretty sure he is not putting 4 foot diffusers on the walls .

I would ask him to orient his speakers toward the couch so that he is hearing more of the on-axis response.

I would ask him to run the tests I suggested for how reflective his room is. If it is too reflective, then he should put more furniture and such in his room to tame that.


And that is the aim in an anechoic chamber. We want to measure a speaker with a mic. If an NE room provides only the direct sound from its speaker, then it can be a replacement for an anechoic chamber. Why is it not that? Why do anechoic chambers have floors that are that way as with front wall? Why not stick a table there and put the mic above it?


From your statements per above. If the ear is only hearing the speaker and no reflections, then I can replace it with a mic and perform anechoic measurements of the speaker.

It is taking a ton of time to answer these long posts. Just want to feel the pulse of the members reading the thread. Are you finding these things useful? If so, what interests you and what doesn't. I am personally out of interest to go much further but if there is value, I will continue .

Man, I have no choice now but to respond! (given my earlie comment about these surveys)

I tend towards them being different sides of the same coin...have always found the more accurate I make it the more real i sounds. Lot's of wiggle room there of course, I might have to raise or cut bass on any given track as an example, but as that is based upon 'accurate initial starting point' (smooth extended bass say) then that salting to taste does not carry with it the baggage supplied by the inaccuracy.

If that made sense.

While I continue to check in to rubber neck at the trainwreck, its mostly a pissing match at this point, and has long since gone off the rails as far as what the OP started with. I'd personally like to see some self restraint where when we start going well off topic, a new thread is created and linked to, but the original thread is left to stay on topic.



That said...I know it won't happen...carry on.

so you believe the only sources of edge diffraction within an acoustical space are from the cabinet? what about mounting surfaces if soffit mounting? or other nearby objects within the room/living room?

oh, and toole does discuss the ETC as he has with Nyal Mellor and Jeff Hedback --- you can view their paper here: Nyal Mellor, Acoustic Frontiers LLC & Jeff Hedback,

http://blog.acousticfrontiers.com/st...ist.%20Rms.pdf

you'll also notice some example rooms at the bottom - eg, a "typical living room" that has been treated without simply relying on existing furniture within the room to achieve the desired acoustical response.

they both have pretty extensive backgrounds in room design and acoustics. curious how many rooms you've designed for your customers?

and while we're on the subject, do you have any issues with how the Erskine Group designs their rooms and the treatment they place at sidewalls? kromkamp does the same (currently absorption; soon to be absorption+diffuser combo). they seem to prefer treatments at the sidewalls. erskine's has quite a portfolio and documentation of highly pleased customers. hmm, why would *he* treat the sidewalls?


no, i asked YOU how YOU utilize the rt60 to decide how much, what types, and where to place measurements. why do you keep referring to other people's work? why can't you speak for yourself based on your past experiences? it should be a relatively easy solution and workflow for you to put forth. why must you constantly rely on the work of others?



i think that harman room is too much of a padded cell to be honest. there are some good % of surfaces coated with thick broadband absorption. padded-cell variety. no thanks. and why such sparse utilization of RPG diffusers in the harman room? why not coat more of the flat surfaces with diffusers? if harman is designing a custom room, why wouldn't they design their own diffusers based on their own bandwidth and sq area requirements? why rely on conventional off the shelf products for a custom room? are your company's reference room diffusers designed from scratch - custom for the room? or are they purchased/off-the-shelf products? i see some auralex and RPG products there - care to elaborate?



ultimate reference? nah, no where near enough meat in his publications, book, etc to be considered an ultimate reference. i do think you have a man-crush on him, though...



no one has ever contested that LF issues is not a priority. and what does the modal region have to do with other important factors like: localization, imaging, spaciousness, envelopment? you insist it is all based on speaker selection. are good room and good speaker mutually exclusive? can a good speaker cure the inherent issues in ANY room?

tell me, how many more subs can the OP fit in his living room? does he have the capability to place them in the ideal locations? or does furniture arrangement dictate sub placement (eg, typical living room design constraints).


sidestepping the question. i dont care what "priority" order you assign tasks - the window at the left sidewall reflection point is going to alter the spectral content and break symmetry with the right wall. are you saying this isn't a priority? where would you put solving this issue in the priority chain? once he has LF addressed, how would YOU then go about addressing this?

and you can mock 4ft diffusers all you want - that's your ignorance. sound has size and my recommendations do not change physics. if you want an object to be 'seen' by a particular wavelength (frequency), then the object (reflector, absorber, diffuser) needs to be large with respect to wavelength in order to be effective. this is physics 101. don't tell me you didn't learn such information in your 'two-day become-an-expert-in-acoustics' training class?


so that will eliminate the colored reflection due to the window? what's the off-axis response of his speaker? turning the speakers is going to solve this problem you say?


what tests would you use for this? how do you determine which surfaces are too reflective and which are not? what is YOUR work flow?



it is not a replacement for an anechoic chamber unless the listener-room response is anechoic as well --- which it is not. didn't i just explain this to you? have you already slipped back into misunderstanding what 'perspective' means?

anechoic chambers don't have a design requirement to have an anechoic response at one location (listening position) like with NER. the requirement is to be anechoic from any source-receiver location. do you not understand customer design requirements?



sidestepping again --- do you or do you not have any experience tracking vocals? building vocal booths? working with singers and what THEY prefer? any experience at all?

So is it your assertion that an anechoic speaker-listener response (to use your terminology) represents accuracy?

IMO this thread has so jumped the shark from the OP question.
(mod, below for humor)


Reminder of post #1.

For the record, I 100% support taking objective, fact based data measurements for directing location of acoustic treatments.
Local and Dragon, while at times may seem "gruff", simply give good advice like that in thread after thread.

Specifically for the non-symmetrical situtation the OP (Skylinestar) has, taking measurements seems only way to truly identify the need to apply acoustic treatments, and where to apply.

Open challenge:
amirm/Local/Dragon (MIA?)/et all;
Start a thread titled "xxx" focused on that subject, etc.
Another titled "yyy" focused on that subject, etc

I'd then suggest locking this thread.....

I am not following you. What does that mean? What subject?

You say we are not on topic but we are. We are all still debating the right advice to OP. Problem is that we can't seem to agree. OP has a set of speakers in the room and one camp says go and do time analysis and put purpose built material on the walls, while the other says perform frequency response measurements, do consider that typical furnishings work as acoustic material and that listening tests show that two ears and a brain are different than a mic and graph. So be careful when you look at spectrum-free graphs like ETC. And jump the gun and automatically think that the problem is above transition frequency/specular region.


Please don't. I don't understand why people suggest such things. It makes it pain in the neck to then quote posts from this thread once it is locked. What good comes out of locking a thread?

BTW, you asked me to write a summary. I did. It had answers to OP in addition to providing a full picture as you had requested. Yet, I saw no feedback from you. It takes time to compose such things and seeing the person who asked for them ignore it, is disappointing .

I went ahead and created this thread on deep dives one way or the other on room acoustics: http://www.avsforum.com/avs-vb/showthread.php?t=1407637

Hopefully we can use it in the future if threads on this topic get long and argumentative.

Worth a shot, thanks Amir

Sorry, I took a new position at work effective 4/1/2012, so busy, and my staff is swamped also, which keeps me busy managing them. Open req's for 3 people in my group, once those potions filled my bandwidth for "hobby" stuff will be more.
I'll post my response this weekend, finishing up my 2nd grade boys cub scout pinewood derby car tonight, tomorrow is the race....