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Author Topic: 3D audio?  (Read 11488 times)

d gauss

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3D audio?
« on: October 05, 2010, 11:19:38 am »

nothing to do with lynn fuston btw Smile

 http://videos.nj.com/star-ledger/2010/09/princeton_universit y_rocket_sc.html
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pete andrews

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Re: 3D audio?
« Reply #1 on: October 05, 2010, 12:20:50 pm »

fascinating.

thanks!


-pete

Barry Hufker

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Re: 3D audio?
« Reply #2 on: October 05, 2010, 01:13:07 pm »

Without knowing more it seems he is using "holography".  By that I mean he is putting left channel audio in the right-hand speaker (and vice-versa) to cancel out any speaker bleed between ears.  It's an old technique that he has either revived or improved...

And it would only work well in that one listening position.

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ssltech

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Re: 3D audio?
« Reply #3 on: October 05, 2010, 01:39:50 pm »

Falls under the general category of 'transaural' processing, which is essentially a parlor trick. -This just appears to be a more complicated version.

-As Barry says, -neither new or particularly useful, in the real world. -with one of the biggest downfalls being the need to have your head ANCHORED to within a fraction of an inch, else it all collapses. -Also, any reflective paths cause dramatic image collapse.

So -all in all- pretty exciting for those of us who don't mind being held in a straitjacket in the center of a padded room.

Keith
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MDM (maxdimario) wrote on Fri, 16 November 2007 21:36

I have the feeling that I have more experience in my little finger than you do in your whole body about audio electronics..

Berolzheimer

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Re: 3D audio?
« Reply #4 on: October 05, 2010, 01:56:16 pm »

Barry Hufker wrote on Tue, 05 October 2010 10:13

Without knowing more it seems he is using "holography".  By that I mean he is putting left channel audio in the right-hand speaker (and vice-versa) to cancel out any speaker bleed between ears.  It's an old technique that he has either revived or improved...

And it would only work well in that one listening position.




I think there's a lot more going on with what he's doing than that.
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Nicky D

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Re: 3D audio?
« Reply #5 on: October 05, 2010, 03:20:19 pm »

my guess is also some form of parlour trick...the fact that it has to be in a chamber and the distance between the speakers is relatively small...and the he spoke of building a wall between left and right....

probably some kind of M/S processing...widening...phase shifting...centre cancelling bullshit with one side delayed differently than the other to give the impression of forward movement...

or even perhaps simply delaying certain freq bands to give the illusion (or would that be reality) that something is hitting you first or later...

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Bill Mueller

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Re: 3D audio?
« Reply #6 on: October 05, 2010, 03:54:02 pm »

I'm not at all saying this is what is going on here, but it just reminded me about once when a very well respected engineer came to me exclaiming about his new speakers. He said they don't sound like anything I have ever heard before, the sound seems like it's coming right out of the middle of your head!

Sure enough.....his speakers were wired backwards.

Bill
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CWHumphrey

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Re: 3D audio?
« Reply #7 on: October 05, 2010, 05:29:26 pm »

In the 80's, it was called "Q Sound".

Nothing to see here.

Cheers,
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Carter William Humphrey

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Barry Hufker

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Re: 3D audio?
« Reply #8 on: October 05, 2010, 06:33:34 pm »

"I think there's a lot more going on with what he's doing than that."

Can you elaborate?

Barry

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Nick Sevilla

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Re: 3D audio?
« Reply #9 on: October 05, 2010, 06:54:48 pm »

Too bad the report was so superficial... it really did not give any further information other than a scientist having a hobby with audio, and making it "better" in some unknown way.

AS usual, TERRIBLE reporter with no real questions, no real answers, and no real information to be gotten from the "report".

If I was a news media teacher, this reporter would have gotten an F.

Cheers
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Berolzheimer

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Re: 3D audio?
« Reply #10 on: October 05, 2010, 07:09:27 pm »

Haven't any of you ever heard of HRTF's, etc?
No parlor tricks, we're talking about serious psychoacoustic science.  Sure it's always had it's limitations but research marches forward.  I don't get why you're all so quick to poo-poo it.
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Berolzheimer

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Re: 3D audio?
« Reply #11 on: October 05, 2010, 07:14:02 pm »

Barry Hufker wrote on Tue, 05 October 2010 15:33

"I think there's a lot more going on with what he's doing than that."

Can you elaborate?

Barry




I'm guessing he's doing some combination of HRTF, Haas delay, doppler, etc. analysis & modeling.  This stuff of course becomes more & more feasable as DSP speeds & modeling algos improve.

http://en.wikipedia.org/wiki/Head-related_transfer_function
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ssltech

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Re: 3D audio?
« Reply #12 on: October 05, 2010, 08:05:26 pm »

I used HRTF's all the time on the Studer D950S and vista consoles, but -and this is important- he's just starting with 2-channel stereo, and delivering to a 2-channel receiving device (the human head).

That means that the only 'processing' info from which anything can be derived is from comparison between the two channels.

HRTF in multitrack mix applications is one thing (and a thing of beauty, at that) but not really applicable to or in any way flexible for stereo-source-only, other than accommodating (extremely fixed) room circumstance. -Since he's obviously gone to great lengths to control the room acoustics (not feasible in real life) and the listener's position (again, not typically feasible unless you're something like an F-16 pilot) then I agree that this is all wankery.

I also agree that the reporter didn't sound able to think their way through what they were reporting on.

This IS transaural processing, it IS a parlour trick, and it's not very useful in the real world.

Also, let's not overlook that since different techniques are used to assemble stereo recordings, (spaced-pair, coincident mic placement, Pan-pot-multichannel, etc) then the inter-channel differences (timing dominant in spaced pair, amplitude-exclusive in coincident and panpot recordings) dictate that there is NO way to generate reliable "3D" from stereo. No more than you can generate reliable stereo from mono.

Nor -incidentally- is this Three dimensions. -This is a peeve of mine, sorry in advance for the rant.

A theoretical 'point' has no dimensions. A 'line' has one dimension. A 'Square' has two dimensions, and a 'cube' has three.

Similarly, Mono is non-dimensional because it resembles a point.. Stereo is actually ONE dimensional, because it resembles a line, where sounds can be placed along a single dimensional range between the two speakers. Quad/surround is TWO dimensional, because there is an added axis of control, as illustrated by the 'square' panning grid which you often see manufacturers use. "Three-Dee" requires an additional VERTICAL component for spatial 3D.

I really wish people would use the terminology correctly. Only things like Periphonic (a type of Ambisonic playback) and true Imax (where the sixth full-range channel is the 'voice-of-god' overhead speaker) can really be called "three-dimensional".

Anything else is marketing hyperbole, and utterly inaccurate. deriving a stable, position-and-reflection-tolerant controllable delivery from two speakers is bovine excrement. Nothing else.

BOSE advertise 'surround from two speakers'. That's a similarly fertilizer-laden claim.

You CAN perform some parlour tricks with two-channel stereo source, and DSP can be used to 'steer' between channels...

But then delivering through two speakers re-limits what you can do, and if you split it through MORE channels, -while you overcome some of the delivery/reception difficulties- you cannot be assured that your decoding is accurate, because of the randomized possible stereo picture assembly techniques.

-What of the Decca Tree now?

Keith
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MDM (maxdimario) wrote on Fri, 16 November 2007 21:36

I have the feeling that I have more experience in my little finger than you do in your whole body about audio electronics..

Nicky D

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Re: 3D audio?
« Reply #13 on: October 05, 2010, 08:23:06 pm »

but the man listening was an AUDIOPHILE..
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Bill Mueller

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Re: 3D audio?
« Reply #14 on: October 05, 2010, 08:33:42 pm »

ssltech wrote on Tue, 05 October 2010 20:05

I used HRTF's all the time on the Studer D950S and vista consoles, but -and this is important- he's just starting with 2-channel stereo, and delivering to a 2-channel receiving device (the human head).

That means that the only 'processing' info from which anything can be derived is from comparison between the two channels.

HRTF in multitrack mix applications is one thing (and a thing of beauty, at that) but not really applicable to or in any way flexible for stereo-source-only, other than accommodating (extremely fixed) room circumstance. -Since he's obviously gone to great lengths to control the room acoustics (not feasible in real life) and the listener's position (again, not typically feasible unless you're something like an F-16 pilot) then I agree that this is all wankery.

I also agree that the reporter didn't sound able to think their way through what they were reporting on.

This IS transaural processing, it IS a parlour trick, and it's not very useful in the real world.

Also, let's not overlook that since different techniques are used to assemble stereo recordings, (spaced-pair, coincident mic placement, Pan-pot-multichannel, etc) then the inter-channel differences (timing dominant in spaced pair, amplitude-exclusive in coincident and panpot recordings) dictate that there is NO way to generate reliable "3D" from stereo. No more than you can generate reliable stereo from mono.

Nor -incidentally- is this Three dimensions. -This is a peeve of mine, sorry in advance for the rant.

A theoretical 'point' has no dimensions. A 'line' has one dimension. A 'Square' has two dimensions, and a 'cube' has three.

Similarly, Mono is non-dimensional because it resembles a point.. Stereo is actually ONE dimensional, because it resembles a line, where sounds can be placed along a single dimensional range between the two speakers. Quad/surround is TWO dimensional, because there is an added axis of control, as illustrated by the 'square' panning grid which you often see manufacturers use. "Three-Dee" requires an additional VERTICAL component for spatial 3D.

I really wish people would use the terminology correctly. Only things like Periphonic (a type of Ambisonic playback) and true Imax (where the sixth full-range channel is the 'voice-of-god' overhead speaker) can really be called "three-dimensional".

Anything else is marketing hyperbole, and utterly inaccurate. deriving a stable, position-and-reflection-tolerant controllable delivery from two speakers is bovine excrement. Nothing else.

BOSE advertise 'surround from two speakers'. That's a similarly fertilizer-laden claim.

You CAN perform some parlour tricks with two-channel stereo source, and DSP can be used to 'steer' between channels...

But then delivering through two speakers re-limits what you can do, and if you split it through MORE channels, -while you overcome some of the delivery/reception difficulties- you cannot be assured that your decoding is accurate, because of the randomized possible stereo picture assembly techniques.

-What of the Decca Tree now?

Keith

I just love this guy. Mind like a steel trap. What he said.

In 1975 a producer, I believe it was Adrian Barber, came to Sheffield with a tape and put it on the two track. In our little control room, you could clearly hear sources coming out the the SIDES of the room, where there happened to be a door on one side and a Scully on the other. I was amazed. We all later heard that same effect on boom boxes as the "width" control.

Bill
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"Don't take it personally. But this shit is a science." J.J.Blair

“The Internet is only a means of communication,” he wrote. “It is not an amorphous extraterrestrial body with an entitlement to norms that run counter to the fundamental principles of human rights. There is nothing in the criminal or civil law which legalizes that which is otherwise illegal simply because the transaction takes place over the Internet.” Irish judge, Peter Charleton
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