Listening in an Anechoic Chamber - a report

[rdenney]

Surely we were discussing listening to recorded music, not making live music. Immense difference.

Well, sort-of. I thought we were talking about what it's like to be in an anechoic chamber.

Rick "who should have deleted the whole message" Denney

 

[dasdoing]

when we are listening to a recorded intrument, we are not trying to make it sound like it is playing in our room. that's a common misconception.
you could do recordings like this by recording the instrument in an anechoic chamber. but that is not how music is recorded. no typical living-room has good acoustic anyways.
So what is done is recording instruments in a place that has good acoustics. stereo was invented as a method to kind of recreate the recorded acoustics via a playback system.

 

[rdenney]

when we are listening to a recorded intrument, we are not trying to make it sound like it is playing in our room. that's a common misconception.
you could do recordings like this by recording the instrument in an anechoic chamber. but that is not how music is recorded. no typical living-room has good acoustic anyways.
So what is done is recording instruments in a place that has good acoustics. stereo was invented as a method to kind of recreate the recorded acoustics via a playback system.

Well, obviously.

But one reason being in a chamber can be disturbing is that our entire experience of hearing is formed in reverberant spaces, and being in an anechoic chamber is therefore unnatural to us. Right now, I hear a bird singing outside, the fan on my computer, my wife rummaging around elsewhere in the house, a blower motor running somewhere, the heating elements on my radiant space heater buzzing, and the persistent tinnitus primarily in my left ear. In a chamber, all I would hear is the tinnitus. It's a bit like putting on noise-canceling headphones. I enjoy them on a plane because there's a limit to how much canceling they can do. But when I put them on in a quiet room, the profound quiet that results is actually disconcerting.

That's why some people are bothered by being in a chamber. For others, it just isn't a big deal. Some people are good on boats; others aren't.

But most speakers were designed to be used in reverberant spaces, and the design targets they used were tested in reverberant spaces used for blind testing. The purpose of an anechoic chamber is to find out what the speaker is doing, not what the room is doing, so that it can then be modeled in any room. I note that McIntosh also had a reverberant room so that they could understand speaker performance when reflections were profoundly dominant. Speakers use the reflections to expand the stage, for one thing. But, as Toole states, we are highly trained in listening through normal reverberation, and distinguishing what is reverberation from what is room. That we can do that for both live music and for playback isn't the same thing as saying that one can never made recorded music sound like live music in the room.

You got to admire the commitment of building a near anechoic space in one's home. I would wonder if that space could not be improve by adding controlled reflectivity in the room, especially for stereo presentations.

Rick "not that committed" Denney

 

[youngho]

So what is done is recording instruments in a place that has good acoustics. stereo was invented as a method to kind of recreate the recorded acoustics via a playback system.

I don't think that quite reflects the history of what we regard as stereophonic sound: "This invention relates to the transmission, recording and reproduction of sound .and is more particularly directed to systems for recording and reproducing speech, music and other sound effects, 15 especially when associated with picture effects as in talking motion pictures. The fundamental object of the invention is to provide a sound recording and reproducing system whereby a true directional impression mav be conveyed to a listener thus improving the illusion that the sound is coming, and is only coming, from the artist or other sound source presented to the eye" (see a reproduction of Blumlein's patent at http://ieeemilestones.ethw.org/images/5/5f/GB394325A(OCR).pdf). Even monophonic sound can convey an impression of the acoustic environment in which it was recorded, but the technique that Blumlein invented is possibly the most mathematically accurate recreation of the original sound field when reproduced through two loudspeakers positioned 45 degrees to each side of midline, as opposed to the typical 30 degree angle in most setups. Thus, most recordings can be regarded as reflecting distortions and embellishments of any of the original spatial characteristics (if such exists, which is not the case for the significant majority of available music), both in recording technique and also reproduction. I don't believe that even Blumlein setups can accurately approximate free field and diffuse field conditions with two loudspeakers.

 

[EEE272]

@rdenney I really liked your thoughts but was wondering about the first.

1.) I expect that most recordings are mixed with the assumption that they will be listened to in normal environments.

In the past, I was also convinced of this but newer recordings might be increasingly optimized for headphones, as this is how most people consume audio now. This could imply that a larger amount of ambiance will find its way into the record. I feel like I can hear this trend when comparing music from different decades. Nevertheless, this is just a thought - I have no proof or sources...
If it were true, then more absorption would be beneficial in the long run.

 

[Axo1989]

View attachment 182312

This is how I imagine Inner Space's listening room now.

 

[DanielT]

This is how I imagine Inner Space's listening room now.

Aha! Now I know what I could say to him in the queue! (see attached picture):
Fix your room acoustics.

By the way, I'm lucky. In terms of furniture, style and acoustics regarding Hifi. I am tired of the bare, white interior style with little furniture in the living room. My listening room is my living room. I focus on more traditional English style nowadays.Not my living room attached picture (plus an example of a white living room) , but I like that kind of style.

 

[rdenney]

@rdenney I really liked your thoughts but was wondering about the first.

1.) I expect that most recordings are mixed with the assumption that they will be listened to in normal environments.

In the past, I was also convinced of this but newer recordings might be increasingly optimized for headphones, as this is how most people consume audio now. This could imply that a larger amount of ambiance will find its way into the record. I feel like I can hear this trend when comparing music from different decades. Nevertheless, this is just a thought - I have no proof or sources...
If it were true, then more absorption would be beneficial in the long run.

Maybe. Maybe not. But I see the increasing domination of headphones as the work of the devil. (Yes, even though I have four pairs of decent headphones and a headphone amp.)

(I’m joking. Sort-of.)

But the main question is the mix of room sound and instrument sound, the former of which might be simulated using reverb processing. Compression and the like probably doesn’t care as much about headphones, but does (in theory) care about ambient noise. But I doubt mastering engineers are turning a recording of road noise on at 65 dB in the mastering room while they are making those decisions, either.

So, I suspect it’s just based on the mood and experience of the mastering engineer at the time, but probably targeted fairly dry in general for “clarity”. Maybe less so that I’m the past, though.

Rick “circle of confusion” Denney

 

[DanielT]

It is an interesting viewpoint to consider, certainly not one I would usually adopt. Force usually implies something much stronger than obligation or requirement, typically involving a high level of threat or coercion extending all the way up to potentially include physical means. Otherwise, on an individual level, I am "forced to" breathe, blink, drink, urinate, eat, and defecate. On a personal level, I am "forced" to provide material necessities for my family and tend to emotional needs. Outside of the house, I am "forced" to wear clothes and refrain from seriously harming people, even if "I would like to do" otherwise. On a professional level, any job could be described as "forced" labor. I would never describe any of these things as being "forced," so I very much see it as hyperbole. (I was going to say something about being forced to follow some modicum of civility on ASR, but that does not seem to have applied in this thread). I find that people often tend to use loaded (negatively) terms when describing viewpoints with which they don't agree.

What you have is basically an extension of control room design, though probably you should have a 1-2' layer of Basotect on the floor between the speakers and the listening position, since floor reflections can be an important source of coloration with effects on both timbre and spatial perception (Bech 1995, 1996, 1998). A rug is not adequate to address the lower frequencies involved.

I do wonder about the absorption of Basotect at non-random-incidence (BASF provides very limited measurements). Toole had provided interesting data from Peter D'Antonio in the first/second edition of Sound Reproduction regarding fiberglass along these lines. It would be interesting to see measurements from your room if you are willing to share any, especially the lower frequency decays.

Hell, how depressing it sounded.

These relationships ....

Conversation taken from a movie, a scene where the woman and the man are arguing and the woman asks (angrily): "But how the hell do you want me to be?!". The man's answer: "How about horny, happy and grateful!"....

Edit:
A little basic, among other things 2:10 into the video.Hear the differences:

 

[Thomas_A]

S

when we are listening to a recorded intrument, we are not trying to make it sound like it is playing in our room. that's a common misconception.
you could do recordings like this by recording the instrument in an anechoic chamber. but that is not how music is recorded. no typical living-room has good acoustic anyways.
So what is done is recording instruments in a place that has good acoustics. stereo was invented as a method to kind of recreate the recorded acoustics via a playback system.

High Fidelity is relative I would say. If the definition is to recreate what the recording engineer heard in the studio, it is hard given that studios differ quite much (e.g. the study by Genelec with highly variable room response curves, even with the same speakers). Another definition is recreating the original event, or the illusion of it. This could include upmixing 2-channel audio to multi-channel, which again, would differ what the recording engineer heard in the studio (two channel recording).

My opinion is use a "lounge model" where the recording venue is an extension of your listening space, i.e. the musicians are there. Meaning that all sound, direct and reflected, is on the record from a typical studio situation. Reflections from your lounge are added, as an extension of the room. The key thing is that the wall that separates you from the musicians should be more or less acoustically "invisible".

The other option is to add ambience channels in your room and use either multichannel records or upmixing to give an impression to be transferred to the event. This is more relevant where recordings are made in a live event and not studios.

The good thing is that we can have both models to choose from. After all, it is just illusions and never perfect ones. Most of the times, IMO, the illusions are however very pleasing.

 

[DanielT]

S


High Fidelity is relative I would say. If the definition is to recreate what the recording engineer heard in the studio, it is hard given that studios differ quite much (e.g. the study by Genelec with highly variable room response curves, even with the same speakers). Another definition is recreating the original event, or the illusion of it. This could include upmixing 2-channel audio to multi-channel, which again, would differ what the recording engineer heard in the studio (two channel recording).

My opinion is use a "lounge model" where the recording venue is an extension of your listening space, i.e. the musicians are there. Meaning that all sound, direct and reflected, is on the record from a typical studio situation. Reflections from your lounge are added, as an extension of the room. The key thing is that the wall that separates you from the musicians should be more or less acoustically "invisible".
View attachment 182500
The other option is to add ambience channels in your room and use either multichannel records or upmixing to give an impression to be transferred to the event. This is more relevant where recordings are made in a live event and not studios.

The good thing is that we can have both models to choose from. After all, it is just illusions and never perfect ones. Most of the times, IMO, the illusions are however very pleasing.

It is possible to use dipole or omni speakers. Fits more or less well depending on the type of recording. You have figure out where in the listening room they should be placed (distance from walls) and find a location that suits your taste, sound ideal. Some people like that kind of sound, wide "big" sound, soundstage. Others think that the sound, after a while of listening just kind of becomes the same and like "smeared"

In which case. That's exactly what's fun with Hifi. To try.

Here is discussed a variant, construction model of speakers regarding this with dipole (similar, variant).Plus a little miscellaneous about omni in that thread. It's mostly about Peter Snell (interesting in itself)
As seen in the thread, different likes and tastes. Those who like that kind of sound, others do not like it:

Backwards directed , rear-firing tweeter, Snell Type E / III?

Anyone have experience with such speakers? What are the advantages and disadvantages? Grateful for response. Snell Type E / III, just to show an example of what I mean:

audiosciencereview.com

 

[dasdoing]

Well, obviously.

But one reason being in a chamber can be disturbing is that our entire experience of hearing is formed in reverberant spaces, and being in an anechoic chamber is therefore unnatural to us. Right now, I hear a bird singing outside, the fan on my computer, my wife rummaging around elsewhere in the house, a blower motor running somewhere, the heating elements on my radiant space heater buzzing, and the persistent tinnitus primarily in my left ear. In a chamber, all I would hear is the tinnitus. It's a bit like putting on noise-canceling headphones. I enjoy them on a plane because there's a limit to how much canceling they can do. But when I put them on in a quiet room, the profound quiet that results is actually disconcerting.

That's why some people are bothered by being in a chamber. For others, it just isn't a big deal. Some people are good on boats; others aren't.

But most speakers were designed to be used in reverberant spaces, and the design targets they used were tested in reverberant spaces used for blind testing. The purpose of an anechoic chamber is to find out what the speaker is doing, not what the room is doing, so that it can then be modeled in any room. I note that McIntosh also had a reverberant room so that they could understand speaker performance when reflections were profoundly dominant. Speakers use the reflections to expand the stage, for one thing. But, as Toole states, we are highly trained in listening through normal reverberation, and distinguishing what is reverberation from what is room. That we can do that for both live music and for playback isn't the same thing as saying that one can never made recorded music sound like live music in the room.

You got to admire the commitment of building a near anechoic space in one's home. I would wonder if that space could not be improve by adding controlled reflectivity in the room, especially for stereo presentations.

Rick "not that committed" Denney

there is a simple reason that creating music and speakers for reverbant spaces is impossible: they all differ
in the past they would calibrate speakers by ear. every speaker sounded diferent (much more tha today), had diferent FR; because they were calibrated in diferent rooms. there is a reason why this is not done anymore

Reflections from your lounge are added, as an extension of the room.

that sounds great in theory. an it looks good in the drawing where the two spaces match perfectly.
In reality you have two confliting spaces, with the worse sounding one being the earlier and therefore more prominent.

 

[Thomas_A]

that sounds great in theory. an it looks good in the drawing where the two spaces match perfectly.
In reality you have two confliting spaces, with the worse sounding one being the earlier and therefore more prominent.

I am aware that I showed more or less "ideal" compartments, but I did so for simplicity. However, the schematics can anyhow be used to position speakers and damping where it works best under those conditions. Meaning a "reduced" LEDE, where reflections from the speaker wall side should be taken care of. The rest of the listening lounge should, IMO, have a reasonable blend of absorption/reflection by normal furniture, mats and such things. The rest is taken care of by our ears and brain.

Damping at and around the speakers similar to as you did in post #10 is a way to deal with it, and improve details from the recording better, but without making the listening space totally "dead dry" and uncomfortable to be in. This is at least my experience.

 

[Thomas_A]

It is possible to use dipole or omni speakers. Fits more or less well depending on the type of recording. You have figure out where in the listening room they should be placed (distance from walls) and find a location that suits your taste, sound ideal. Some people like that kind of sound, wide "big" sound, soundstage. Others think that the sound, after a while of listening just kind of becomes the same and like "smeared"

In which case. That's exactly what's fun with Hifi. To try.

Here is discussed a variant, construction model of speakers regarding this with dipole (similar, variant).Plus a little miscellaneous about omni in that thread. It's mostly about Peter Snell (interesting in itself)
As seen in the thread, different likes and tastes. Those who like that kind of sound, others do not like it:

Backwards directed , rear-firing tweeter, Snell Type E / III?

Anyone have experience with such speakers? What are the advantages and disadvantages? Grateful for response. Snell Type E / III, just to show an example of what I mean:

audiosciencereview.com

Speakers are important too, but what comes to mind are speakers designed to make the wall "disappear" (Carlsson). Then there are subjective parameters what you like more in terms of the amount of reflections, speaker directivity etc.

 

[kongwee]

I posted this in another topic


I now temporarily introduced a little no-reflection-zone. (this is just to avaliate if I move further from the front-wall; this is closest position).



View attachment 181825

this is probably 1/10 of the material I have only....man the diference is crazy. I imediatly feel taken away from my room and thrown into the ambience of the recording.
Like I said in the quoted post, I listend to the bare room for a few days so I get used to it and hear the diference. The diference is day and night. the bare room sounds just broken. Notice though that there is no carpet and no couch and other stuff. So without the material it is very reflective

Put on curtain on the window. Even those off the shelf. It is easy tweak.

 

[dasdoing]

Damping at and around the speakers similar to as you did in post #10 is a way to deal with it, and improve details from the recording better, but without making the listening space totally "dead dry" and uncomfortable to be in. This is at least my experience.

I do like it better than the all-dead aprouch I had before. the clarity is there; the late reflections only seam to add size.

Put on curtain on the window. Even those off the shelf. It is easy tweak.

the speaker plane is below the windows. windows are not good acousticly, but I like day-light too much. also they would hide my ocean-view....the only reason I moved up two floors

 

[Thomas_A]

I do like it better than the all-dead aprouch I had before. the clarity is there; the late reflections only seam to add size.

Try this one, and play loud.

 

[Frgirard]

Why listen to music in an anechoic chamber ? it's a challenge, are is there anything to gain ?

An anechoic chamber has nothing to do with a Non Environmental Studio (floor, console...). And listen music in a room with a low decay is not unpleasant. As far as I know, the loudnesswar warriors do not submit to daily torture sessions, neither the fans of listening to headphones nor me for that matter.

it will always be a question of preference for listening and recording and/or production technique for the production.

 

[dasdoing]

Try this one, and play loud.

that's some greate ambience there. great choir. and no overdriven mics. just the right thing I needed after I added a panel to the backwall. Even though I wanted to make the room less dead the backwall treatment will be necessary (1st mode). to my surprise the room doesn't seam to get more dead. atm, sliding the panel in and out of the room, I am not sure which I prefer. the image doesn't realy seam to change. I guess I'll try difusion in the back at some point. on the ETC the backpanel has a more drastic effect, basicly eliminating 3 spikes

 

[youngho]

I found another interesting quote from Sigfried Linkwitz: "I have observed occasionally that highly directional loudspeakers in a highly absorptive environment with low reflections can produce a center phantom source, a female voice that floats in front of the line between the loudspeakers. In an anechoic room the center phantom source can even manifest inside the head, which mimics headphone listening" (https://www.linkwitzlab.com/TMT-Leipzig'10/TMT-Hearing spatial detail.pdf)