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Topic: What is high fidelity multichannel audio? (Read 13773 times) previous topic - next topic
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What is high fidelity multichannel audio?

The vinyl vs. cd thread wound up drifting off into a bunch of different things, but one point which I think requires a LOT more discussion is the nature of surround sound in a rational high fidelity context.

David has mentioned hearing some pretty spectacular surround sound tests that gave an excellent sense of realism. I wanted to start a thread about this whole idea. Ignore the issue of finding music to play on these systems for a moment.
  • What is sonic "realism" in the context of surround sound? Is it merely the presence of a natural soundstage? Is it the increased ability to discriminate between different locations in the soundscape? Is it an increased coherence of a single sound source in the soundstage? Can it at all be quantitatively defined?
  • How can it be consistently achieved in real-world listening environments? Can it be reasonably constructed in Ye Olde Crappy Computer Room?
  • Is there any way to achieve it in a DIY fashion with speakers?
  • Is there any way to achieve this at all with headphones? (Save for the vaporware SVS?)
  • Is sonic realism something that people even care about in a commercial context nowadays?

What is high fidelity multichannel audio?

Reply #1 –
Just to repeat(!) the answer isn't 5.1.

For most music, 5.1 is effectively just stereo, with a bit of echo added behind, and a redundant channel added in the centre.

The "real" centre channel can be useful, but it's hardly a killer addition in the context of a decent listening set-up. Stereo already solves this "problem" in a typical "audiophile" listening set-up.


In terms of the huge discussion you're trying to start, I think you were spot-on at the end of the last thread - people have been burnt by surround sound already - it's hard to convince them that something new is it - and the industry is in no rush to try.


Can it work over headphones? Yes - but the "best" headphone experience is good binaural, and how often does that happen? Ambisonics > binaural isn't as good as a direct recording (AFAIK), and anything less transformed for use over headphones is even less exciting. None of it works properly over really cheap headphones, and (IMO) none of it gives convincing out-of-the-head sounds in front of you - unless either (a) motion tracks, and/or (b) with a visual cue. Neither happens on an iPod on a train!

Cheers,
David.

P.S. the sursound mailing list, and its archives, are a great place to learn about and discuss this topic...

http://mail.music.vt.edu/mailman/listinfo/sursound/

What is high fidelity multichannel audio?

Reply #2 –
Quote from: 2Bdecided on
Just to repeat(!) the answer isn't 5.1.


Perhaps not 5.1, but the answer *is* 'multichannel sound', not 2-channel. 

Quote
For most music, 5.1 is effectively just stereo, with a bit of echo added behind, and a redundant channel added in the centre.


I've been reading Floyd Toole's book for the past week or three, and he seems to disagree with you to a degree here. 

Toole writes at length about two factors -- 'apparent source width' (ASW), a broadening of the soundstage derived from (IIRC) direct and early reflected sound from the front array (LCR), and 'listener envelopment' (LEV), derived from late reflections (or surround channels, in a typical home listening space).  Both ASW and LEV are signifiers of listener preference in controlled tests... listeners seem to want them, when given the chance.  So I would not be so dismissive of surround -- and in fact, I myself prefer DPL II on virtually *all* two-channel material, in my own setup. 

Perhaps you and Toole meet in that 'most music' is a studio creation rather than a real 'acoustic' event; but 'live' classical recordings , and recording that do attempt to capture the venue ambience, do exist too. The studio creations can be made more 'real sounding' by the addition of 'echo' deployed in surround speakers; the 'live' recordings can be better replicated by surround playback too.

Interestingly, though, both live unamplified music and home repro with good LEV and ASW, tend NOT to offer the sort of pinpoint imaging that much of the 'high-end' dotes on.  Toole has a sidenote that listener preference from  tests of LEV and ASW, does not necessarily predict repro preference of *musicians* --and by extension, anyone, like recording engineers and perhaps 'audiophiles',  so-called 'sensitive listeners' who takes a more analytical approach to listening.

Almost every page of his book has interesting stuff to chew on...I'm really enjoying my leisurely read-through.


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The "real" centre channel can be useful, but it's hardly a killer addition in the context of a decent listening set-up. Stereo already solves this "problem" in a typical "audiophile" listening set-up.


Meaning, a setup where the one listener sits rigidly in a sweet spot, and doesn't move his head? 

Toole has a good section on the utility of the C channel, too -- and how it often isn't properly exploited in multichannel music mixes.


Quote
In terms of the huge discussion you're trying to start, I think you were spot-on at the end of the last thread - people have been burnt by surround sound already - it's hard to convince them that something new is it - and the industry is in no rush to try.



Who has been 'burnt' by surround sound?  Since the days of quad, I mean?  I'd bet it's been the only significant growth sector of the home audio gear industry for some time,  (unless you count iPods ;> )

What is high fidelity multichannel audio?

Reply #3 –
krabapple,

If you haven't already, please have a look at the two links in Axon's post on the words "pretty spectacular". You'll see I'm a huge fan of multi-channel, just not 5.1.

I don't have Toole's book - it looks interesting from Amazon's "look inside". However, it has just two pages on Ambisonics, and (from the contents page at least!) implies that LCR is the/a way to deliver first lateral reflections. I think I might get irritated with it quite quickly, so it's probably not a good use of £24 of mine.

Cheers,
David.

What is high fidelity multichannel audio?

Reply #4 –
Quote from: krabapple on
Toole writes at length about two factors -- 'apparent source width' (ASW), a broadening of the soundstage derived from (IIRC) direct and early reflected sound from the front array (LCR), and 'listener envelopment' (LEV), derived from late reflections (or surround channels, in a typical home listening space).  Both ASW and LEV are signifiers of listener preference in controlled tests... listeners seem to want them, when given the chance.  So I would not be so dismissive of surround -- and in fact, I myself prefer DPL II on virtually *all* two-channel material, in my own setup.
Are those (ASW/LEV) the only important factors discussed by Toole? It seems to me like focusing on the width and depth of the soundstage is a little shortsighted. And it kind of validates David's point.

Also, how close does DPL II come to achieving the soundstage expansion otherwise done with surround formats?

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Perhaps you and Toole meet in that 'most music' is a studio creation rather than a real 'acoustic' event; but 'live' classical recordings , and recording that do attempt to capture the venue ambience, do exist too. The studio creations can be made more 'real sounding' by the addition of 'echo' deployed in surround speakers; the 'live' recordings can be better replicated by surround playback too.

Interestingly, though, both live unamplified music and home repro with good LEV and ASW, tend NOT to offer the sort of pinpoint imaging that much of the 'high-end' dotes on.  Toole has a sidenote that listener preference from  tests of LEV and ASW, does not necessarily predict repro preference of *musicians* --and by extension, anyone, like recording engineers and perhaps 'audiophiles',  so-called 'sensitive listeners' who takes a more analytical approach to listening.
That's really counterintuitive for me.

One thing I would expect with a system with "pinpoint imaging" is that (for well recorded material) the instruments become more distinctly separated. At some point, the cocktail party effect kicks in, and it should become much easier to separate out one instrument from another. This should allow music that would otherwise sound jumbled and confusing in a 2-channel environment with poor imaging to sound much clearer in multichannel. (For example, my wife can stop complaining about how far back Sadier's voice is on Stereolab songs.)

In other words, like (it seems) how lowering the noise floor and flatting the frequency response/distortion seems to help people listen to dynamic music like jazz/classical they would not otherwise listen to, improving the imaging resolution of the playback should allow complicated music to become more comprehensible. That seems like a pretty big win to me, and one that could move units a lot faster than merely widening the soundstage would.

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Quote
In terms of the huge discussion you're trying to start, I think you were spot-on at the end of the last thread - people have been burnt by surround sound already - it's hard to convince them that something new is it - and the industry is in no rush to try.

Who has been 'burnt' by surround sound?  Since the days of quad, I mean?  I'd bet it's been the only significant growth sector of the home audio gear industry for some time,  (unless you count iPods ;> )
That might be true, but I don't think anybody cares about soundstage width/depth anymore, at least with music. In other words, if the parameters Toole found important really were that important, DVD-A/SACD (hell even DAD) probably would have pulled themselves up by their own bootstraps by now.

What is high fidelity multichannel audio?

Reply #5 –
I have to combine quotes because ot the forum's damnable ten-quote limit.

Quote from: Axon on
Are those (ASW/LEV) the only important factors discussed by Toole?

///
It seems to me like focusing on the width and depth of the soundstage is a little shortsighted. And it kind of validates David's point.


No, not the only factors, though the book is very heavily focuses on the effects of reflections..  And I'm only halfway through the book. 
\
Toole's focus in regard to ASW and LEV is based in published listening tests.

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Also, how close does DPL II come to achieving the soundstage expansion otherwise done with surround formats?


I couldn't give you a quantitative answer.  But for me it can achieve both a soundstange expansion and the illusion of listener envelopment, depending on the source material.  Other times it behaves more like quadrophic mixes, where 'special' panning effects are emitted from the surrouns speakers, rather than just 'ambience enhancement'


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That's really counterintuitive for me.

One thing I would expect with a system with "pinpoint imaging" is that (for well recorded material) the instruments become more distinctly separated. At some point, the cocktail party effect kicks in, and it should become much easier to separate out one instrument from another. This should allow music that would otherwise sound jumbled and confusing in a 2-channel environment with poor imaging to sound much clearer in multichannel. (For example, my wife can stop complaining about how far back Sadier's voice is on Stereolab songs.
//

In other words, like (it seems) how lowering the noise floor and flatting the frequency response/distortion seems to help people listen to dynamic music like jazz/classical they would not otherwise listen to, improving the imaging resolution of the playback should allow complicated music to become more comprehensible. That seems like a pretty big win to me, and one that could move units a lot faster than merely widening the soundstage would.


Non-pinpoint, non-distinctly separated instrumental imaging is how live ensemble music sounds in live, 'acoustic' spaces.  You are talking about studio creations.

Again, it is not about merely widening the soundstage, it is about that plus listener envelopment, plus the results of letting listeners rate preference.


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That might be true, but I don't think anybody cares about soundstage width/depth anymore, at least with music.



Again, I think you should read the book (it has in-text citations and a bibliography).  I don;t imagine Toole would lie about preference test results.


Quote
In other words, if the parameters Toole found important really were that important, DVD-A/SACD (hell even DAD) probably would have pulled themselves up by their own bootstraps by now.



DVD-A and SACD has *other* marks against them (need to buy new players, for example; lack of content was another) and the mixes there were by no means always intended to sound 'real' in terms of listener envelopment.  Another factor working against multichannel music-only releases is the popular association of surround sound with MOVIE sound rather than music.

You're also assuming people typically have their surround systems configured up well enough to give them a real shot at benefitting from  better ASW and LEV.  I suspect there's a lot of leeway, but one would AT LEAST want the speaker distance (delay) settings to be somewhere near correct.

What is high fidelity multichannel audio?

Reply #6 –
I have nothing useful to contribute on sound reproduction, but one observation on "pinpoint imaging" in live performance.

I regularly attend live performances of baroque music, esp. Bach choral pieces, in an acoustically less-than-perfect space. I normally sit in the front row, to get the drama and involvement bit. But at one, rather good, performance of Handel's Ode for St Cecilia's Day, I was sitting half-way back, well off-centre. I noticed that I had no very strong impression of directionality at all. For some of the ensemble singing, the effect was very powerful--the music seemed to come from everywhere; but for the soloists, the effect of being able to see the singer in a specific spot, but have the voice generalised, was slightly odd--but not disconcerting.

FWIW.

What is high fidelity multichannel audio?

Reply #7 –
I can agree that I was probably off the mark in expecting tight directionality in a realistic surround sound performance. I can admit to not experiencing a whole lot of directionality in the live (amped or acoustic) performances I've been to.

But ultimately that isn't reassuring me at all. The gist I'm getting out of this discussion is that surround sound is, first and foremost, useful for creating a more realistic and immersive soundstage - not for more detail. This, I feel, is a very substantial difference compared to the advantages stereo has over mono. While stereo also has huge soundstage advantages over mono, I think that the ability to resolve details is generally much better with a stereo recording than with a mono one, simply because instruments are better separated in the soundstage. Good surround, if I'm getting the gist of what all of you are saying, doesn't do that nearly as much.

In my mind, that makes surround sound a much less compelling popular music format. I would argue that most people just do not care about such things, even when they buy a surround system. (Otherwise they would be caring a lot more about how the damn things get set up.) On the other hand, those people would care if it meant that music they love (or otherwise would love) is not as understandable or clear without the specific advantages that surround sound can provide.

In other words: Even if detail isn't a priority in the advancement of surround sound... shouldn't it be?

What is high fidelity multichannel audio?

Reply #8 –
It's not like everything becomes a gigantic nebulous blur where it's impossible to tell that the basses are on the right and the violins on the left.    Widening the soundstage can increase sense of space between the instruments, too...and a center channel can absolutely anchor the vocal image in the middle.  A significant part of the work Toole cites deals with speech intelligibility, as well as music reproduction.

Remember too, that the envelopment effect doesnt' necessarily hold for studio creations -- where overdubs, direct injection of signal to board, and a host of postprocessing moves, including totally man-made placement of instruments and vocals in the mix by the engineer, may render the whole idea of 'realistic' reproduction moot. Ditto any movie soundtrack. There are plenty of surround mixes where there is little if any attempt to recreate the sense of a live ensemble playing unamplified instruments in a real space... instead the whole idea is to create new forms of instrumental separation, or even new 'listener vantages' (some surround mixes put the listener 'onstage' with the musicians). I don't think either one is in danger of snuffing out the other.

I would suggest, again, that you check out  Toole's book to see all of what he has to say about stereo vs multichannel, and all of the evidence he has marshalled.  I can't really relay the contents of a ~400 page tome, chock full of citations, adequately here.  I would say though that there is NOTHING that 2.0 can do , that surround CAN'T do, while the opposite is not true.

What is high fidelity multichannel audio?

Reply #9 –
I have nothing of any real value to add. I just wanted to say that I'm with krabapple on this. I use "Dolby ProLogic II Music" mode on my home system for all 2-channel music listening and it definitely improves the whole listening experience immensely for me. I'll just add at this point that my system (as with many others) has the facility to "fill in" the gaps between speakers and provides a full 360 degree sound field, and my listening chair is slap-bang in the sweet-spot. I've never been in a situation where the sound field seems plain "wrong" in any way. It just works perfectly for me personally all the time.

Could I truly quantify what I hear in words? No. Definitely not. I wouldn't know where to start to be honest.

Cheers, Slipstreem. 

What is high fidelity multichannel audio?

Reply #10 –
I wouldn't think that music that is typically amplified in a live venue has many benefits with more than 2 channels as the live performance typically consists of loudspeakers sitting on either side of a stage, with everything (including a drummer sitting behind a drum-shield) mic-d through them.

elevatorladylevitateme

What is high fidelity multichannel audio?

Reply #11 –
Quote from: Axon on
In other words: Even if detail isn't a priority in the advancement of surround sound... shouldn't it be?


That's the point. Just as stereo opens up the sound, surround can open the sound even further. It gives instruments more space to breathe. Arguing about 'realistic' and 'unrealistic' is all a matter of perspective. In my university days, I managed to walk almost right through a full orchestra during a rehearsal. That was the most 'unreal' experience of my life. The physical space afforded each instrument a life I'd never heard before (or since). Textures and tones separated out like that are so rich and detailed. It was literally a moving experience and one I will never forget.

So - can surround recreate this kind of intimacy with music? I've heard instances. A piano in the middle of the room (as if it was right there with you) on Steely Dan's 'Two Against Nature' DVD showed promise. It's a dimension that just can't be achieved with stereo, at any price. I have a friend who experimented with binaural recording way back when it was all the rage (you stick 2 microphones in the 'ears' of a foam 'head' and record what they 'hear'). Pretty freaky stuff, but 'practically' impossible to recreate with current recording techniques.

None of this fifth row centre business, the conductor's position is the ultimate sweet spot. I played support for a big name recording band once and managed to stick around to hear their stage sound - it was a musician's dream. No matter what the 'house' sound was like, they played every night in the most beautiful and inspiring audio environment. And you could tell by their performance.

Yes there is a heaven and I've heard it in both orchestral and rock environments. Fine stereo is a wonderful thing. It's like being in the audience of a performance. But fine surround is like standing beside your favourite performer while they play.

It's not all about 'realism' either, just as recording itself, offers unique sonic experiences, stereo even more so, surround offers even more unique experiences. And now that "most" homes have some kind of surround system, I think it's time music moved into the third dimension.

Just this week I got my hands on a 192/24, 10 channel out recording interface & I'm going to do my best to recreate 'the real thing' as I've experienced it. Now if someone can just tell me how I can get it (uncompressed) on to a Blu-ray, I'll be able to share it.

What is high fidelity multichannel audio?

Reply #12 –
Quote from: shakey_snake on
I wouldn't think that music that is typically amplified in a live venue has many benefits with more than 2 channels as the live performance typically consists of loudspeakers sitting on either side of a stage, with everything (including a drummer sitting behind a drum-shield) mic-d through them.


Depending on the types of instruments used, there can easily be a lot of spill directly from the instruments into the audience. Then. there can be secondary spill from the artist's monitor speakers into the audience.

At the place where I do most of my live sound work, the percentage of spill ranges from well over 3/4 in the front few rows, to maybe 1/4 in the back, which is row 26.  The live spill that makes it to the back is pretty well corrupted by being bounced around some pretty nasty walls.

What is high fidelity multichannel audio?

Reply #13 –
Quote from: Axon on
The vinyl vs. cd thread wound up drifting off into a bunch of different things, but one point which I think requires a LOT more discussion is the nature of surround sound in a rational high fidelity context.


It that can happen, then HA is IME the likely spot for it to happen. SNR is very good around here.

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David has mentioned hearing some pretty spectacular surround sound tests that gave an excellent sense of realism.


With all due respect, so it was said. I say that there was no proper evaluation of whether the recordings were presented realistically given that *nobody* reporting their opinions was actually present at the live performance. Therefore, what really happened is that someone compared what they heard at the demo to what they imagined the live performance sounded like. Shakey ground, anybody?

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  • What is sonic "realism" in the context of surround sound?


It is the same thing that it is for any other kind of sound reproduction. Realism is realism. Do we need to define realism?  Realism is not being able to ABX the recording from what you would hear in your favorite listening position at the live performance.

And, you can come pretty close to this using very good headphones, and a binaural recording. That's 2.0 channels. This seems to be the basis of some of Sean Olive's recent postings here.

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Is it merely the presence of a natural soundstage?


Do you know what a natural sound stage is? I question that very highly because so many people lack the ability to have free range at a live performance. OTOH, I do it all the time, at least 6 times this week. Unforutnately, the musicans are amateurs, the music is music that not everybody appreciates, and the rooms vary from wretched to average and a lot of a time there is a SR system active in the room.

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Is it the increased ability to discriminate between different locations in the soundscape? Is it an increased coherence of a single sound source in the soundstage?


I see that someone already gave you your reality check on this issue.  There isn't all that much discrimination and coherence in the real world. Sit in row 1 and things are already pretty well fuzzed up.


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Can it at all be quantitatively defined?


Cross correlations, anybody?

The real question is cross correlation with what?

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  • How can it be consistently achieved in real-world listening environments?


Yes, binaural listening really works.


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Can it be reasonably constructed in Ye Olde Crappy Computer Room?


Yes, with the right recordings and headphones.



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  • Is there any way to achieve it in a DIY fashion with speakers?


You can get pretty close to headphones with good near field monitors.


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  • Is there any way to achieve this at all with headphones? (Save for the vaporware SVS?)


Yes, with binaural recordings.

BTW, your post was truncated by HA's Nazi-esque policy on numbers of quoted blocks. I'm tired of fighting it. I'm just going to respond naturally and chop stuff off the bottom until I can post it. loss of content notwithstanding.


What is high fidelity multichannel audio?

Reply #14 –
Quote from: Bgrant on
It's not all about 'realism' either, just as recording itself, offers unique sonic experiences, stereo even more so, surround offers even more unique experiences. And now that "most" homes have some kind of surround system, I think it's time music moved into the third dimension.

Just this week I got my hands on a 192/24, 10 channel out recording interface & I'm going to do my best to recreate 'the real thing' as I've experienced it. Now if someone can just tell me how I can get it (uncompressed) on to a Blu-ray, I'll be able to share it.


You can find some professional-quality tracks to play with out in the world of torrents. Classic top-40  tunes such as "Woman don't cry" by Marley and "Suspicion" by Wonder.  Based on about a decade's worth of experience, you are probably better off working with high grade tracks from others as opposed to trying to line up talent and recording it on your own.

What is high fidelity multichannel audio?

Reply #15 –
Thanks for replying.

Binaural does work, but unless you have the musicians all playing together in a perfectly acoustic room and a perfectly mixed environment, then stick the recording mics right in the middle, you're stuck with trying to mix multi-tracked binaural recordings, which isn't as easy as it sounds. Even then, you're stuck with 'dry' instrument recording and so many modern instruments don't actually exist in the acoustic space (drums, synthesisers etc.). And let's not even try to figure out how to record vocalists in with all those instruments. Maybe for acoustic performances. And I guess there's an opening for multi-tracked binaural recording… for the enterprising sound engineer. At least you could get that to work on an iPod, actual sound quality aside. I wonder if you can get a couple of really nice Neumann mics into a styrofoam head. (And yes, I realise Neumann make a binaural head).

Isn't it strange that surround mixes are for 1970s recordings. I've got a few DVD-As and they're nice enough, but it was the 70s and recording quality has improved an awful lot since then. I listen to Queen or Yes in surround and think, well, the mix is nice enough, but it's still 70s sound quality and that leaves a lot to be desired. There's a lot of stunning 60s vocal performances (Nat King Cole etc.) with the most gorgeous (and expensive) plate reverb, but the actual quality of the recorded product is dismal. Sure it sounded better in the studio than on the LP, but things sound so much better in the studio, these days.

I get what you're saying about the performance is the thing. No Digital Audio Workstation playing midi controlled samples of a bass player can come anywhere near a good bass player. The point of getting a decent quality interface is so that MY recordings turn out the way I'd like them to be heard. Maybe I'm not the best drummer, bass player, keyboard player or guitarist, but if I can get my vision of what recording -could be- realised, I'll be able to encourage the best musicians I know to participate.

I'll let you know how I get on with my surround experiments. I can't imagine the file sizes will be anything like uploadable/downloadable. Maybe 20 or 30 second snippet's.

What is high fidelity multichannel audio?

Reply #16 –
At the risk of re-starting an argument, I have no desire to hear what it sounds like half way back in the concert hall. Usually too muddy, often too quiet, and without the visual cue and the "you are there" excitement it's quite lacking. I prefer the normal sound of CDs.

Lots of older classical music wasn't played in concert halls anyway - it was played in nice rooms in country houses, or at home. Plenty of "stereo separation" in real life back then - and the people in the "best" seats were sat right at the front.

Obviously larger (and some smaller) orchestral works fall apart if you can actually hear individual instruments - they need to blend together - but I don't want to hear mono with a bit of echo!


I think many good 60s recordings sound great today. There are fundamental technological limitations, but they don't really detract from the listening pleasure for me. If the master tape is damaged, or only a 4th generation dub is available, then yes - it's not as good - but a decent master tape is still good enough for musical enjoyment, unless the only mix that exists is really strange/nasty. Of course the "effects" (like the plate reverb mentioned) are also technologically limited - they're part of the charm of the recording, but if the multitracks exist you can add modern reverb if you want. There are some specific Nat King Cole examples - some releases use a 1960s mix with lots of reverb, other releases of the same album have no reverb at all. Both "Live at the Sands" and "Nat King Cole sings / The George Sheering quintet plays" are like this.

Cheers,
David.

What is high fidelity multichannel audio?

Reply #17 –
Quote from: Bgrant on
Binaural does work,


And very well, but it does not suit a well-defined problem, which you are providing more evidence about.

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but unless you have the musicians all playing together in a perfectly acoustic room and a perfectly mixed environment, then stick the recording mics right in the middle,


One of the major problems with binaural is that it by far works the best at reproducing things that actually happened, as they happened.
This is because audiophiles in general are not interested in realistic recordings.  Aside from that, binaural's realism is a severe problem because it can take a lot of resources to make something that sounds good actually happen.

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you're stuck with trying to mix multi-tracked binaural recordings, which isn't as easy as it sounds.


Multitracking isn't that much of a solution for binaural recordings because of their realism with respect to the actual event. OK, I could make multitrack binaural recordings by having the various artists and instruments show up one at a time, sit in their designated places, and modify the rest of the environment to compensate for the absorbtion, diffusion, and reflections caused by the instruments and players that are not there. I believe I could simply add the tracks together and end up with something that makes sense I'm still stuck with needing a concert hall in order to have concert hall sound. I'm still stuck with a recording that  only sounds really good to people wearing headphones.

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Even then, you're stuck with 'dry' instrument recording


Not if I did things *right* as outliined above.

It seems to me that coming up with a magic transformer that transforms a recording of an instrument playing in a nearly-anechoic studio into a recording that includes the sonic perspective of the same thing happening in the concert hall of my dreams would e possible. IOW, a process that turns a dry recording into a wet recording, but with the wetting agent of my choice.

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and so many modern instruments don't actually exist in the acoustic space (drums, synthesisers etc.).


A simple job for my wetting agent if we could solve the problem of making it. BTW I believe that my wetting agent may already exist.

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And let's not even try to figure out how to record vocalists in with all those instruments.


Same problem, same solution.

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Maybe for acoustic performances.


If it takes a lot of wetting agent to simulate an acoustic performance, it should just take less of a different wetting agent to simulate other acoustic scenarios.


What is high fidelity multichannel audio?

Reply #18 –
The link to this document from NARAS, the Recording Academy has been posted a couple of times in different threads, it gives recommendations with respect to mixing in surround. (not very much about recording that I remember).

There are 2 main kinds of surround approaches, ambient (trying to recreate the sense of being in an acoustic space) and discrete, also called "in the band" "on stage" or the like (have the different part spread around the room instead of only the front).

I'm with Bgrant in that I find the latter type far more exiting, the first kind of recording/mix is usually much more subtle.

Modern recording (well since the 60's that is) most often uses multitracks for everything and then somebody places all those elements in a stereo mix. Of course the same thing can also be done in a surround mix (4.0, 5.0 or 5.1 doesn't matter that much).
What I mean is, the surround mix isn't more unnatural when everything is recorded on separate tracks anyway. It takes a bit of getting used to from the listener side and some don't like it. (Also persons with very expensive stereo setups are often not prepared to make the step, that's OK of course, but some start bashing surround sound just for that reason).

my 2ct I guess.
In theory, there is no difference between theory and practice. In practice there is.

What is high fidelity multichannel audio?

Reply #19 –
Thanks GeSomeone for posting the NARAS document. Invaluable. My project is essentially for my entertainment only, so I have my own ideas, but it's great to have the collected wisdom on hand ('the classics') to check the soundness of all arguments.

For example - my target listening system is 6 identical speakers (curse those voice-centric centre speakers), with full range capabilities (a sub in each speaker). I'm not interested in downmixing or systems with less capability. Is there any point in an LFE in this setup? Well, if receivers did actually send full-range to all speakers, there probably wouldn't. I don't believe they do, on my listening tests (although I've never specified no-LFE in the hardware setup - so many tests, so little time). And as separate amplifiers for each speaker (and a bi-amp for each sub), no matter how ideal, is beyond my budget, the NARAS document will be much needed 'food for thought' when dealing with the inevitable compromises.

I liked your comment about surround mixing, compared to surround recording. Much of the recording software is predicated on this distinction, I guess because of the phenomenal amount of processing involved in recording in surround, as opposed to first recording (essentially mono instruments) and later mixing them 'surround'. I can see why it's done this way (processing power), but it's primitive and self-defeating & unfortunately a fact of the state of the art. Sigh. At the moment I'm trying to decide between Logic and Digital Performer to do the recording/mixing and they both seem to separate recording from mixing in the case of surround, so if anyone has any experience/comments either way, I'd dearly love to hear about the pros and cons of each application.

I'm still curious about binaural, given the popularity of iPods. Clearly, surround is better - you get entirely different sensations if you turn your head in a surround setup (and none at all in binaural). Years ago, I imagined multitrack binaural would be easily (artificially) achieved by a simple programme for placing sounds around binaural space, based purely on different arrival times of sounds/frequencies for the left and right ears. Maybe that's too simplistic, or maybe I have the subject for my Masters and I really need to get back to university. (Know anyone who would sponsor me??) Imagine then if two mixes could be created at the same time, from the same surround source data (position & reverberation information) - one for surround and a slightly lesser binaural mix, visceral in its own way for portable listening phenomenon…

A proper stereo mix can place sounds behind the listener, but surround opens up more substantial possibilities. And as I originally noted - surround is becoming commonplace.

I completely agree, surround suffers the same "audiophile" prejudices that multitrack recording suffers - that it's somehow more artificial. (Once you use a microphone, it's all artificial, baby!) Multitrack recording was invented because better separation and better fidelity can be achieved using specialised mics suited to each instrument (often in an isolated acoustic environment, again for reasons of separation and fidelity). What multitrack (arguably) doesn't do well is capturing the blending of instruments (unless they are recorded in blend-groups), but modern music is less about acoustic blending of sounds, than, say, 'classical' music is. I had to 'chuckle on the inside' when I visited an exclusive audiophile shop and the owner was trying to convince me of the (apparently newly discovered) sonic possibilities of a centre speaker. It was all I could do not to shout, "It only took you 10 years to realise that? How long before you can apply the same logic to surround speakers?" What made it more 'entertaining' was that the owner kept a photograph of his beloved speakers in the Abbey Road studio, in full surround configuration. I would have asked about that, but I fear the self-contradictory rationalisations that would have been employed, would have caused me to laugh out aloud.