What is audio meant to do?

[Kal Rubinson]

And of course this is related to the 'hear through the room' controversy. In a live performance, the listeners 'hear through the room' to the acoustic sources and separate the reverberation from the sources. But the recording doesn't provide enough information to allow the listener to do that, and so the recording sounds a lot more reverberation-heavy than the original performance if mic'ed from the same position

A large part of that is the conflation of all the reflected cues (including the reverberation) with the direct signal and the distortion of their directionality by putting all in a stereo pair aimed at the listener only from the front of the listening room. Distinguishing direct cues from room/ambiance is greatly dependent on directional cues.

A close-mic'ed recording coupled with a real listening room restores some real acoustic space (even though it's just a domestic room's acoustics) to the performance.

Yes but that works only for small sources (up to a handful of performers). Attempting it with a large ensemble like an orchestra is disturbing (as one can appreciate with the Denon disc referred to above).

In my mind's eye it is adding a bit of genuine 'spatiality' to an otherwise static recording which is why I don't want to remove it by 'correction' (surely the ultimate aim of 'room correction'..?) or speakers that beam directly to my ears.

Not really.

 

[Cosmik]

I'm trying to think through whether head-tracking may go some way toward mitigating this obstacle...

You can head track at the reproduction end, but the recording end is fixed. Maybe you need a 3D matrix of finely-spaced minuscule microphones at the recording, allowing you to interpolate between their outputs in real time at replay... sort of thing. Unfortunately, I think they would interfere with each other. And other problems.

The alternative is to record dry and synthesise the acoustics at replay, based on a model of the room and the dispersion of the sources - as they do in computer games. It's not a recreation of the original soundfield exactly - but it might be quite convincing.

 

[andreasmaaan]

You can head track at the reproduction end, but the recording end is fixed. Maybe you need a 3D matrix of finely-spaced minuscule microphones at the recording, allowing you to interpolate between their outputs in real time at replay... sort of thing. Unfortunately, I think they would interfere with each other. And other problems.

I agree.

 

[andreasmaaan]

Affect and engagement. The whole idea of recreating the event is predicated on recreating the experience and there is more to this than the acoustic dimension, though that is the primary focus.

Perhaps holodecks will be the closest we ever come unless we can inject the experience directly into our brains and thus make us believe we are experiencing something that is not actually occurring. Still our attempts at capturing acoustic events do produce affect of their own type. I believe a lot of this has to do with musical cognition so that elements can be abstracted from the recording, even a poor one. There is also the fact that listening to recordings is a skill we have developed -- we can unpack them in our minds and create aural scenes.

Still something eludes us and that is why we are chasing ever higher fidelity.

I agree with all this, but I should have been more specific and used the term "acoustic event" rather than merely "event". I meant the former.

 

[maverickronin]

And yes, I'm trying to separate the possibility of "being fooled" (which in any case was done over 100 years ago with terrible quality equipment) from the theoretical possibility of transparently recreating an acoustic event exactly as it was when it occurred, including in terms of soundfield, which is the one aspect that our current model of recording and loudspeaker reproduction can never - even in purely abstract terms - do correctly.

I think it's also important to note that audio fidelity is usually the least important factor in "being fooled". The attention dedicated to active listening, prior knowledge, and prior listening experience are much more important factors. A cheap mantle radio for the 30's can fool you into thinking you hear a conversation in the next room while you're making a sandwich in the kitchen but sitting in your listening room in front of a giant set of speakers, staring at all the electronics running/powering them, pressing play on a streamer app, sitting back to concentrate exclusively on the music is another thing entirely.

 

[Cosmik]

Yes but that works only for small sources (up to a handful of performers). Attempting it with a large ensemble like an orchestra is disturbing (as one can appreciate with the Denon disc referred to above).

I missed the bit about the Denon disc. Disturbing? I never find orchestral recordings literally disturbing, but one thing I'm never sure of is that when people say "listening room" they might be talking about an almost-empty room with hard floor and walls and maybe a vestigial, token rug in the middle. (Do a google image search on listening room audio to see what I mean). The acoustics are going to be vastly different from my room which has wall-to-wall carpet and furniture in it.

Note really.

Do you mean that you would want the ideal pair of speakers to beam directly into your ears, and for room correction to eliminate the contribution of the room?

 

[maverickronin]

Do you mean that you would want the ideal pair of speakers to beam directly into your ears

At that point you might as well just use headphones instead. Perfect beam forming to your ears will remove most of your HRTF as well as the acoustic crosstalk which stereo mixes rely on for proper spatial localization.

 

[Cosmik]

At that point you might as well just use headphones instead. Perfect beam forming to your ears will remove most of your HRTF as well as the acoustic crosstalk which stereo mixes rely on for proper spatial localization.

So what about 'crosstalk cancellation' and speakers? If you could achieve it effectively and across the full bandwidth, would it actually make sense?

 

[svart-hvitt]

At that point you might as well just use headphones instead. Perfect beam forming to your ears will remove most of your HRTF as well as the acoustic crosstalk which stereo mixes rely on for proper spatial localization.

FWIW, due to the (virtual) point source design of Genelec speakers 8331 and 8341 the speaker distance can be shorter than 0.5 meters and still have correct driver info summation:

https://www.genelec.com/sites/defau...ues/genelec_step_by_step_setup_guide_2017.pdf

I’ve never tried listening at such minimal distances, but it should be worth a test. And these days, the speakers don’t cost more than a pair of those high-end headphones.

At very short distances you save a lot of headroom too.

 

[maverickronin]

So what about 'crosstalk cancellation' and speakers? If you could achieve it effectively and across the full bandwidth, would it actually make sense?

I don't see what it would be good for besides listening to binaural recordings on speakers instead of headphones. You'd basically need music specifically mixed for them.

It could make a pretty devastating sonic weapon though. Classic rock and other older mixes full of hard pans may sound great on speakers but I find them absolutely unlistenable on headphones without at least crossfeed, and preferably a good HRTF DSP. Even new mixes with much less stereo separation will give me headaches after a while with most headphones.

FWIW, due to the (virtual) point source design of Genelec speakers 8331 and 8341 the speaker distance can be shorter than 0.5 meters and still have correct driver info summation:

https://www.genelec.com/sites/default/files/media/Studio monitors/Catalogues/genelec_step_by_step_setup_guide_2017.pdf

I’ve never tried listening at such minimal distances, but it should be worth a test. And these days, the speakers don’t cost more than a pair of those high-end headphones.

At very short distances you save a lot of headroom too.

Those are pretty damn cool. The primary reason I use headphones is space constraints. Those 8331/8341 look pretty damn cool. Such short listening distances open up mounting possibilities that are feasible for me, but damn they're expensive...

 

[andreasmaaan]

Attempting it with a large ensemble like an orchestra is disturbing (as one can appreciate with the Denon disc referred to above).

I had a listen to these recordings today. Was surprised to find them less disconcerting than I'd expected when played through the living room system, which is a crappy 2.1 satellite system (albeit one I'm quite happy with for what it's normally used for, which is background music).

In fact, the most off-putting thing I heard was the very high level of tape hiss, which is obviously specific to these recordings (apart of course from the distortion when played at SPLs approaching normal acoustic levels due to massive strain on these little speakers).

Anyway, I think I could possibly get used to recordings like this....Will need to have a listen over the high fidelity system in my (currently under-reconstruction) studio before even beginning to reach any conclusions though...

FWIW, another major first impression is that this type of recording really seems to force into focus the acoustic of the playback space, making the playback room even more important than in the case of normal non-anechoic recordings.

 

[Cosmik]

Not sure where to post this link
https://www.soundstagehifi.com/index.php/international/soundstage-uk/1177-speaking-of-sad-bastards

Ken Kessler laying into the dying hi-fi industry in comparison to the thriving watch industry.

It stirs memories of how I used to perceive hi-fi (not the more prosaic 'audio'), a perception which I think has become lost. The perception, at least, was that expensive hardware yielded a luxurious experience. It went hand in hand with the way music was recorded in those days: as 'hi' in 'fi' as possible - not deliberately adding distortion and noise with plugins and so on. (And I also have a theory about faulty logic causing studios to EQ their speakers wrongly these days, leading them to shave the top end off when making the recordings).

It's probably why I have built my speakers using recycled 70s enclosures - still uber-stylish.

 

[Fitzcaraldo215]

I had a listen to these recordings today. Was surprised to find them less disconcerting than I'd expected when played through the living room system, which is a crappy 2.1 satellite system (albeit one I'm quite happy with for what it's normally used for, which is background music).

In fact, the most off-putting thing I heard was the very high level of tape hiss, which is obviously specific to these recordings (apart of course from the distortion when played at SPLs approaching normal acoustic levels due to massive strain on these little speakers).

Anyway, I think I could possibly get used to recordings like this....Will need to have a listen over the high fidelity system in my (currently under-reconstruction) studio before even beginning to reach any conclusions though...

FWIW, another major first impression is that this type of recording really seems to force into focus the acoustic of the playback space, making the playback room even more important than in the case of normal non-anechoic recordings.

As a primarily classical music listener with intimate familiarity with live concerts of different scale in halls of different sizes, I fundamentally disagree with your premises. Yes, perfect reproduction of live sound is only an ideal, and will never be practically achievable. However, huge progress toward the goal has been made in my lifetime.

But, reflected sound in the concert hall is not the enemy, as you would have it. The direct + reflected sound field as we hear it there is inseparable, each being an integral part of the sonic stimulus. Reflections are nature's own amplifiers. Reflections can do good things, but they can also distort sound. However, good concert halls retain desireable reflections adding warmth, spaciousness and envelopment to the sound that people over the ages have found preferable.

Do you honestly prefer the sound of live acoustic instruments outdoors unmodified by reflections both of the emitted direct sound and the received sound you hear? This replicates your anechoic recording and playback idea. I most certainly do not, and I am doubting you and most others find it preferable to the sound in the hall.

So, killing all the reflections is not desirable. What is desirable is capturing and reproducing them faithfully with the same balance as live and maintaining their spatial cues, acoustic cues and natural sense of hall envelopment. This is the goal of most classical discrete Mch recording today, and I find it succeeds extremely well in creating a plausible "you are there" sonic replica of the live concert experience. For whatever reasons, it is ignored or dismissed by many audiophiles, but how many have actually heard it vs. stereo in a properly set up Mch system? It may not be perfect, but I find it a major step forward.

And, no, your listening room cannot add back the live sense of space and envelopment heard in the hall to a stereo recording. The listening room dimensions are totally inadequate and the directional properties of the resulting sound field are also totally inadequate. In my experience, artificial upmixing algorithms also fall considerably short of discretely recorded Mch.

 

[svart-hvitt]

As a primarily classical music listener with intimate familiarity with live concerts of different scale in halls of different sizes, I fundamentally disagree with your premises. Yes, perfect reproduction of live sound is only an ideal, and will never be practically achievable. However, huge progress toward the goal has been made in my lifetime.

But, reflected sound in the concert hall is not the enemy, as you would have it. The direct + reflected sound field as we hear it there is inseparable, each being an integral part of the sonic stimulus. Reflections are nature's own amplifiers. Reflections can do good things, but they can also distort sound. However, good concert halls retain desireable reflections adding warmth, spaciousness and envelopment to the sound that people over the ages have found preferable.

Do you honestly prefer the sound of live acoustic instruments outdoors unmodified by reflections both of the emitted direct sound and the received sound you hear? This replicates your anechoic recording and playback idea. I most certainly do not, and I am doubting you and most others find it preferable to the sound in the hall.

So, killing all the reflections is not desirable. What is desirable is capturing and reproducing them faithfully with the same balance as live and maintaining their spatial cues, acoustic cues and natural sense of hall envelopment. This is the goal of most classical discrete Mch recording today, and I find it succeeds extremely well in creating a plausible "you are there" sonic replica of the live concert experience. For whatever reasons, it is ignored or dismissed by many audiophiles, but how many have actually heard it vs. stereo in a properly set up Mch system? It may not be perfect, but I find it a major step forward.

And, no, your listening room cannot add back the live sense of space and envelopment heard in the hall to a stereo recording. The listening room dimensions are totally inadequate and the directional properties of the resulting sound field are also totally inadequate. In my experience, artificial upmixing algorithms also fall considerably short of discretely recorded Mch.

FWIW, I had the pleasure of losing my direction in a European old town this summer, went into the yard of a convent and heard a «sacral» choir inside. Magic! That sound could never have been made in open air. I was soakingly swet, in shorts and a t-shirt and dared not walk inside the halls. The fear is always your enemy; I wish I had the courage.

So I guess reflection and the room can very much be your friend, and in some cases it makes you connect with the sacred.

 

[Cosmik]

And, no, your listening room cannot add back the live sense of space and envelopment heard in the hall to a stereo recording. The listening room dimensions are totally inadequate and the directional properties of the resulting sound field are also totally inadequate.

I don't know if that was me you were thinking of, but I wasn't suggesting that the room can do that. I'm thinking of it more like the final smidgeon of analogue filtering at the output of a DAC's digital filter. Just a little morsel of real acoustics that reflects from around you and responds to your head movements, unlike the completely static recording. It also binds the recording with the listeners at that moment in that the same acoustics are responding to the recording and also to the listeners' speech etc. In multi-channel it may serve to blur the edges between the discrete channels.

Again, I'm not talking about the echoey wooden-floored spaces seemingly favoured by most audiophiles, but a room with a carpet and furniture.

 

[andreasmaaan]

@Fitzcaraldo215, actually I love the sound of reflections and concert halls. I even prefer audio listening rooms to be quite reverberant (and large) as I said in a previous post. So I seem to be very much with you in terms of what my preferences are and what I enjoy both in live performances and in audio reproduction.

My observations on the anechoic orchestral recordings were not a comparison to recordings in concert halls. I just pointed out that I didn't find the sound as off-putting as I'd expected to. I certainly prefer the sound of good orchestral recordings taken in concert halls (although to be fair I need to listen to the anechoic recordings on a proper system before I write them off).

In the context of current approaches to recording and reproduction, I also agree with your point that "killing all the reflections is not desirable."

However, going back to my OP, my point is not about what is desirable. My point was actually far more abstract, seeking to spark a discussion about the goals of audio recording and reproduction, which are often stated to be something along the lines of: "recreation of the original performance/acoustic event."

Or to put it in your terms:

What is desirable is capturing and reproducing [reflections] faithfully with the same balance as live and maintaining their spatial cues, acoustic cues and natural sense of hall envelopment.

I was trying to demonstrate why, on a philosophical level, this goal is not achievable when, in recordings, we have sounds radiating from multiple sources within a reverberant space captured at a single point in space (the mic), and then reproduced out of a single source (or sources) in a listening space.

If you need applied evidence of this, think of the way an orchestra is typically mic'd for concert hall recordings. Normally, we don't simply use a Blumlein pair placed a head's width apart in the best seat in the house, even though it is the acoustic at precisely this point that we are trying to create in the recording. Most engineers agree that this is not the best way to "capture" the desired spatial cues.

Instead, we place mics in all sorts of very different locations (depending on the engineer). So we are not maintaining the hall's spatial and acoustic cues, and there is little acoustically natural about the placement of our mics. Quite the opposite: we are using creative microphone placement in an attempt to artificially generate these cues in a way that merely seems to reproduce the effect of being in the best seat in the house when played back on typical loudspeakers.

I totally agree with this approach by the way. It's a way of compromising for the inadequacies inherent in actually using the true spatial cues a listener in the hall would experience at the live performance (i.e. the spatial cues present in the best seat in the house).

So I think that at best, a fairly convincing and enjoyable, but very much artificial, effect is achieved.

 

[eis]

"We aren't at a point where our audio systems fool us into believing that a real even is taking place in our home."

(IMO) Each of us has an individual experience as to how we perceive music. (that to me is the wonderful thing about this hobby)
I never go to un-amplified concerts. Everything I listen to is amplified in some way.
So in my little world what is happening in my listening room is a real event... to me.
Even so, I still strive to buy equipment that has been engineered and measures well in addition to treating the room acoustically.

 

[Kal Rubinson]

I missed the bit about the Denon disc. Disturbing? I never find orchestral recordings literally disturbing, but one thing I'm never sure of is that when people say "listening room" they might be talking about an almost-empty room with hard floor and walls and maybe a vestigial, token rug in the middle. (Do a google image search on listening room audio to see what I mean). The acoustics are going to be vastly different from my room which has wall-to-wall carpet and furniture in it.

My listening room is far from empty, carpeted and has a moderate level of acoustical treatments. Nonetheless, the (almost) anechoic recordings make it sound as if it was somewhat bare.

Do you mean that you would want the ideal pair of speakers to beam directly into your ears, and for room correction to eliminate the contribution of the room?

Nope. What I was responding to was your statement "to remove it by 'correction' (surely the ultimate aim of 'room correction'..?)." I would change the word "remove" to "control." Room acoustics are a necessary contribution, especially when recordings are mastered to sound best in domestic rooms and when recordings are limited to 2 channels.

 

[svart-hvitt]

I forgot to ask this question, so let me now put it forward before I forget it again:

=> IS THERE A DIFFERENCE BETWEEN SOUND AND AUDIO?

And does the way you define the terms determine how you think about the question of the OP?

 

[Fitzcaraldo215]

@Fitzcaraldo215, actually I love the sound of reflections and concert halls. I even prefer audio listening rooms to be quite reverberant (and large) as I said in a previous post. So I seem to be very much with you in terms of what my preferences are and what I enjoy both in live performances and in audio reproduction.

My observations on the anechoic orchestral recordings were not a comparison to recordings in concert halls. I just pointed out that I didn't find the sound as off-putting as I'd expected to. I certainly prefer the sound of good orchestral recordings taken in concert halls (although to be fair I need to listen to the anechoic recordings on a proper system before I write them off).

In the context of current approaches to recording and reproduction, I also agree with your point that "killing all the reflections is not desirable."

However, going back to my OP, my point is not about what is desirable. My point was actually far more abstract, seeking to spark a discussion about the goals of audio recording and reproduction, which are often stated to be something along the lines of: "recreation of the original performance/acoustic event."

Or to put it in your terms:


I was trying to demonstrate why, on a philosophical level, this goal is not achievable when, in recordings, we have sounds radiating from multiple sources within a reverberant space captured at a single point in space (the mic), and then reproduced out of a single source (or sources) in a listening space.

If you need applied evidence of this, think of the way an orchestra is typically mic'd for concert hall recordings. Normally, we don't simply use a Blumlein pair placed a head's width apart in the best seat in the house, even though it is the acoustic at precisely this point that we are trying to create in the recording. Most engineers agree that this is not the best way to "capture" the desired spatial cues.

Instead, we place mics in all sorts of very different locations (depending on the engineer). So we are not maintaining the hall's spatial and acoustic cues, and there is little acoustically natural about the placement of our mics. Quite the opposite: we are using creative microphone placement in an attempt to artificially generate these cues in a way that merely seems to reproduce the effect of being in the best seat in the house when played back on typical loudspeakers.

I totally agree with this approach by the way. It's a way of compromising for the inadequacies inherent in actually using the true spatial cues a listener in the hall would experience at the live performance (i.e. the spatial cues present in the best seat in the house).

So I think that at best, a fairly convincing and enjoyable, but very much artificial, effect is achieved.

OK, good, I am happy that we are in somewhat general agreement on anechoic reproduction. You had me worried there. Yes, we also agree on Blumlein. It has failed commercially for many valid reasons, but that does not prevent some audiophiles from reenerginizing some myths about it here and there.

However, we still fundamentally disagree on whether the goal of properly reproducing multiple sound sources, direct and reflected, is achievable. So, you may not realize it, but you therefore seem to turn your back on phantom imaging, which is the fundamental way that stereo works, and Mch relies on it heavily, too. Phantom imaging between speakers has its limits, and it is less perfect than discrete speakers, but we are generally happy with sound between not fully panned L-R in stereo, hence a phantom image. Mch can use this front L-R phantom imaging, augmented by a center channel which improves it, in addition to phantom imaging between surround and main channels.

But, seriously, you seem to be implying that a mic channel cannot walk and chew gum at the same time. And, that it cannot pick up multiple sounds at the same time, be they direct on axis or off axis, real or reflected sound, but only one sound source at a time. I don't think this squares with reality at all. Mics pick up all sounds within their pickup pattern. They pick up a sound field, not individual instruments, not indidual spatial or reverberant signatures. And, in the case of Mch, the diffuse nature of reflected hall sounds is consistent with the less precise nature of phantom images acquired by the mics in multiple channels from different perspectives. It all comes together on playback from a congruent Mch speaker array. It is a complex system, with a complex sum greater than the sum of the individual components.

From my discussions with Mch classical recording engineers, I can assure you that in most cases every attempt is made, in spite of mic channel count, to provide a proper balance between direct and reflected sound in order to maintain a satisfactory spatial image of the front soundstage and the reflected sound field heard by the audience. They do mix and master using the same angular speaker array as specified for home playback. You only assume that their mic technique is detrimental to proper spatial capture, but without evidence. And, again, there are examples far too numerous to name of recordings successfully demonstrating this from minimalist to extensively multi-mic'ed. I think your comment on the inadequacies of the engineering indicates that you likely may not have actually heard those numerous examples in a proper system. I have, and, personally, the effect does not sound artificial at all, certainly not compared to the limitations of stereo.