PSYCHOACOUSTICS AND I

[Fitzcaraldo215]

What you have is a recording made with some static microphones that, to whatever degree the recording person captured it, contains direct and ambient sound. You are welcome to listen to the recording in an anechoic chamber on speakers (if necessary sitting very still and using BAACH type cross-channel cancellation) or with headphones whereupon it can be arranged for you to perfectly hear the recording as it was made. Sitting very close to some small speakers would also get close to this 'ideal'. This will give the perfect measurements at the listening position that everyone says they want. Directionality of the speakers wouldn't matter because you would only be hearing the direct sound.

However, in conflict with that, the way I see it is that you may wish to listen to the recording in a real room because:
(1) You want your listening to be compatible with ordinary domestic life (used to be true in, say, the 1970s, but for modern audiophiles with their dedicated listening chambers is less true now).
(2) Real added room ambience provides some dynamic ambience that overcomes the static nature of the recording; that responds to your head (micro-)movements. It also helps to bind real ambient sounds (when you talk, etc.) with the recording as opposed to the peculiar sensation of listening to a recording of a reverberant cathedral, but your own voice and movements being reverberation free.

The quantity of this added room ambience is related to the directionality of the speakers. Sure, on strictly scientific grounds, it doesn't represent a perfect facsimile of the trumpet in a room, but it does represent a static recording of something that sounds very similar to the trumpet with added dynamic ambience - ambience derived from the recording in a coherent, 'correct' physical system that our hearing is able to interpret without added effort; naturally separating the direct from the ambient, and enjoying the ambience. Speaker directionality is a way of controlling the ratio of direct to reverberant sound that is naturally correct/coherent/interpretable by human hearing. Piping in 'ambience' from some separate remote drivers wouldn't be the same because our hearing would identify that it wasn't naturally derived from the direct sound.

Capturing the direct sound of instruments might be most all of what some people want. For example, pop music recorded in relatively dead studios with artificial reverb, and other effects added "artistically" in mixing and mastering a stereo recording. That works for many and can deliver a good musical experience if well engineered. But, it is not what I want.

As a classical music listener, what I want is some closer replica of the sound I hear in the audience in a seat in the hall. That sound is much more than just the direct sound of the instruments. In most seats other than the first few rows, it has been shown empirically that the sound field we hear in the hall is dominated by diffuse reflected energy, which is greater in total magnitude than the direct sound from the stage. Typically, we are unaware of that reflected energy, unless it is taken away. The Haas or precedence effect masks some reflected energy, and, together with visual cues and the less diffuse and earlier arrival of direct sound, it fools us into believing the sound is all or mostly all coming from the performers on the stage, which it is not.

Stereo does take much of that natural reflected sound away, lest the reproduced sound be too cavernous. Or, it redirects a truncated fraction of it to the listener purely from the front, which is not consistent with the omnidirectional character of the sound field in the hall.

Can the listening room recreate a replica of the sound in the hall by adding its own reflections to stereo playback? No. It is wishful thinking for classical. The listening room is much too small compared even to most chamber music venues seating one hundred or more, let alone orchestra halls, opera halls, etc. seating thousands. Acoustic path lengths are much too short and their delay insufficient to remotely begin to replicate the reflected sound field in the hall.

I refer to the belief that the room can recreate the sound field at a classical concert as the Bose Fallacy. Bose was inspired by classical music reproduction, and he made and published measurements of classical performances in the hall. But, his speakers, while they succeeded commercially, did not achieve, to my ears and many others, an adequate reproduction of a live concert via stereo. Radiating TO everywhere with high levels of reflected sound out the back of his stereo speakers is simply not the same as sound emanating FROM everywhere, as occurs in the hall.

There are also differences in the frequency character of the reflected sound vs. direct. The reflected hall sound attenuates the highs, emphasizing the mids and bass - greater warmth? Listening room reflections do not do that to the same degree or from the same directions. Also, Toole cites the persistent center sound stage crosstalk attenuation of even direct sounds centered at around 2k Hz in stereo speakers via phantom imaging. The center speaker in Mch eliminates this, delivering a more accurate center sound stage, both in frequency response and in spatial reproduction. With video, this also can deliver superior dialog articulation. This is another precious nugget from Toole's latest book.

So, for the classical music I prefer, I want to hear the reflected sound field of the hall together with the direct sound from the performers on stage. So, in general, I disagree with:

"Piping in 'ambience' from some separate remote drivers wouldn't be the same because our hearing would identify that it wasn't naturally derived from the direct sound."

I am not a fan of artificial ambience added to stereo recordings. I listen mostly to recordings done in discrete, natively recorded Mch. The natural ambience from hall reflections and coming at me from surround speakers and phantom imaging between all channels in the Mch system is quite a different matter from simulated Mch.

Mch sounds much more, not less, natural to me. It is much more consistent with what I hear at a live concert. Stereo sounds like it is coming from "over there", all from up front. Mch provides a superior frontal soundstage and it envelops me like a live concert with natural reflected ambiance coming from the right directions, captured via discrete Mch. Toole, by the way, generally agrees on Mch for music, goes to many live classical concerts and he has a 7.1 system in his home.

Bottom line, to me it is adequate reproduction of the sound field heard live that matters, not just reproduction of individual instruments. Stereo on any system in any room I have ever heard it just cannot do that adequately with classical music, IMHO. Fine tuning of the system, the listening room and the speakers may be worthwhile in achieving greater uncolored sonic purity, but it still comes up short for me in stereo.

 

[Cosmik]

Capturing the direct sound of instruments might be most all of what some people want. For example, pop music recorded in relatively dead studios with artificial reverb, and other effects added "artistically" in mixing and mastering a stereo recording. That works for many and can deliver a good musical experience if well engineered. But, it is not what I want.

As a classical music listener, what I want is some closer replica of the sound I hear in the audience in a seat in the hall. That sound is much more than just the direct sound of the instruments. In most seats other than the first few rows, it has been shown empirically that the sound field we hear in the hall is dominated by diffuse reflected energy, which is greater in total magnitude than the direct sound from the stage. Typically, we are unaware of that reflected energy, unless it is taken away. The Haas or precedence effect masks some reflected energy, and, together with visual cues and the less diffuse and earlier arrival of direct sound, it fools us into believing the sound is all or mostly all coming from the performers on the stage, which it is not.

Stereo does take much of that natural reflected sound away, lest the reproduced sound be too cavernous. Or, it redirects a truncated fraction of it to the listener purely from the front, which is not consistent with the omnidirectional character of the sound field in the hall.

Can the listening room recreate a replica of the sound in the hall by adding its own reflections to stereo playback? No. It is wishful thinking for classical. The listening room is much too small compared even to most chamber music venues seating one hundred or more, let alone orchestra halls, opera halls, etc. seating thousands. Acoustic path lengths are much too short and their delay insufficient to remotely begin to replicate the reflected sound field in the hall.

I refer to the belief that the room can recreate the sound field at a classical concert as the Bose Fallacy. Bose was inspired by classical music reproduction, and he made and published measurements of classical performances in the hall. But, his speakers, while they succeeded commercially, did not achieve, to my ears and many others, an adequate reproduction of a live concert via stereo. Radiating TO everywhere with high levels of reflected sound out the back of his stereo speakers is simply not the same as sound emanating FROM everywhere, as occurs in the hall.

There are also differences in the frequency character of the reflected sound vs. direct. The reflected hall sound attenuates the highs, emphasizing the mids and bass - greater warmth? Listening room reflections do not do that to the same degree or from the same directions. Also, Toole cites the persistent center sound stage crosstalk attenuation of even direct sounds centered at around 2k Hz in stereo speakers via phantom imaging. The center speaker in Mch eliminates this, delivering a more accurate center sound stage, both in frequency response and in spatial reproduction. With video, this also can deliver superior dialog articulation. This is another precious nugget from Toole's latest book.

So, for the classical music I prefer, I want to hear the reflected sound field of the hall together with the direct sound from the performers on stage. So, in general, I disagree with:

"Piping in 'ambience' from some separate remote drivers wouldn't be the same because our hearing would identify that it wasn't naturally derived from the direct sound."

I am not a fan of artificial ambience added to stereo recordings. I listen mostly to recordings done in discrete, natively recorded Mch. The natural ambience from hall reflections and coming at me from surround speakers and phantom imaging between all channels in the Mch system is quite a different matter from simulated Mch.

Mch sounds much more, not less, natural to me. It is much more consistent with what I hear at a live concert. Stereo sounds like it is coming from "over there", all from up front. Mch provides a superior frontal soundstage and it envelops me like a live concert with natural reflected ambiance coming from the right directions, captured via discrete Mch. Toole, by the way, generally agrees on Mch for music, goes to many live classical concerts and he has a 7.1 system in his home.

Bottom line, to me it is adequate reproduction of the sound field heard live that matters, not just reproduction of individual instruments. Stereo on any system in any room I have ever heard it just cannot do that adequately with classical music, IMHO. Fine tuning of the system, the listening room and the speakers may be worthwhile in achieving greater uncolored sonic purity, but it still comes up short for me in stereo.

I don't think your comment overlaps with the quoted one of mine to any great extent!

For sure, I am not expecting my listening room to duplicate the ambience of the venue - that is hopefully captured in the recording, and as such it sounds OK when wearing headphones. But I want the listening room to add some of its own ambience for the reasons in my comment above. Not as a means of reproducing an ambience that isn't present in the recording; but as supplementing the recorded ambience with some 'dynamic sound fields' as it were. If you are completely dismissive of the value of the listening room's ambience and seek the flattest frequency response at the listening position then you should be looking into building a very dead room or sitting close to the (surround) speakers. This will give the highest objective accuracy by conventional criteria.

 

[Fitzcaraldo215]

I don't think your comment overlaps with the quoted one of mine to any great extent!

For sure, I am not expecting my listening room to duplicate the ambience of the venue - that is hopefully captured in the recording, and as such it sounds OK when wearing headphones. But I want the listening room to add some of its own ambience for the reasons in my comment above. Not as a means of reproducing an ambience that isn't present in the recording; but as supplementing the recorded ambience with some 'dynamic sound fields' as it were. If you are completely dismissive of the value of the listening room's ambience and seek the flattest frequency response at the listening position then you should be looking into building a very dead room or sitting close to the (surround) speakers. This will give the highest objective accuracy by conventional criteria.

Well, it would not be the first time that I went off on a tangent chasing ghosts in my imagination. But, I thought I was commenting particularly on the one sentence of yours I cited, and generally on ambience recovery by the listening room.

No, I do not want a dead room, to sit near field or listen to headphones. I also do not wish to apply acoustic treatments or try to tune the room, other than trying to choose a room of sufficient size to which I add normal furnishings and finishes, etc. in a way that might randomize absorption, diffusion, etc. Then, I apply DSP EQ full range. There may be some remaining acoustic signature of my room, but as you say we adapt to it over time anyway, as long as it is not outrageously bad. Toole agrees. And, by the way, he emphasizes the role of the recording in determining the ultimate quality of the listening experience, often superceding the speakers and room.

I highly recommend that latest Toole book, though you might be put off by his reliance on experiments on human subjects - psychoacoustics.