Path: utzoo!attcan!uunet!lll-winken!lll-lcc!ames!mailrus!cornell!batcomputer!riley
From: riley@batcomputer.tn.cornell.edu (Daniel S. Riley)
Newsgroups: comp.graphics
Subject: Re: Sound tracing (Academic Snooty-ness)
Keywords: Ray tracing, sound tracing
Message-ID: <7103@batcomputer.tn.cornell.edu>
Date: 4 Jan 89 04:21:43 GMT
References: <239@raunvis.UUCP> <413@cs-spool.calgary.UUCP> <7488@watcgl.waterloo.edu> <3435@uoregon.uoregon.edu> <572@epicb.UUCP>
Reply-To: riley@tcgould.tn.cornell.edu (Daniel S. Riley)
Organization: Cornell Theory Center, Cornell University, Ithaca NY
Lines: 60

In article <572@epicb.UUCP> david@epicb.UUCP (David P. Cook) writes:
>>In article <7488@watcgl.waterloo.edu> ksbooth@watcgl.waterloo.edu (Kelly Booth) writes:
>>>[...]  It is highly unlikely that a couple of hackers thinking about
>>>the problem for a few minutes will generate startling break throughs
>>>(possible, but not likely).

Ok, I think most of us can agree that this was a reprehensible attempt
at arbitrary censorship of an interesting discussion.  Even if some of
the discussion is amateurish and naive.

>  The statement made above
[...]
>  Is appaling!  Sound processing is CENTURIES behind image processing.
>		If we were to apply even a few of our common algorithms
>		to the audio spectrum, it would revolutionize the
>		synthizer world.  These people are living in the stone
>		age (with the exception of a few such as Kuerdswell [sp]).

On the other hand, I think David is *seriously* underestimating the
state of the art in sound processing and generation.  Yes, Ray Kurzweil
has done lots of interesting work, but so have many other people.  
Of the examples David gives, most (xor'ing, contrast stretching,
fuzzing, antialiasing and quantization) are as elementary in sound
processing as they are in image processing.  Sure, your typical
music store synthesizer/sampler doesn't offer these features (though
some come close--especially the E-mu's), but neither does your vcr.
And the work Kurzweil music and Kurzweil applied intelligence have done
on instrument modelling and speech recognition go WAY beyond any of these
elementary techniques.

The one example I really don't know about is ray tracing.  Sound tracing
is certainly used in some aspects of reverb design, and perhaps
other areas of acoustics, but I don't know at what level diffraction
is handled--and diffraction is a big effect with sound propagation.
You also have to worry about phases, interference, and lots of other
fun effects that you can (to first order) ignore in ray tracing.
References, anyone?  (Perhaps I should resubscribe to comp.music, and
try there...)

(off on a tangent:  does any one know of work on ray tracers that will
do things like coherent light sources, interference, diffraction, etc?
In particular, anyone have a ray tracer that will do laser speckling 
right?  I'm pretty naive about the state of the art in image synthesis,
so I have no idea if such beasts exist.  It looks like a hard problem
to me, but I'm just a physicist...)

>No, this is not a WELL RESEARCHED area as Kelly would have us believe.  The
>sound people are generally not attacking sound synthesis as we attack
>vision synthesis.  This is wonderful thinking, KEEP IT UP!

Much work in sound synthesis has been along lines similar to image
synthesis.  Some of it is proprietary, and the rest I think just
receives less attention, since sound synthesis doesn't have quite
the same level of perceived usefullness, or the "sexiness", of
image synthesis.  But it is there.  Regardless, I agree with David
that this is an interesting discussion, and I certainly don't mean
to discourage any one from thinking or posting about it.

-Dan Riley (dsr@lns61.tn.cornell.edu, cornell!batcomputer!riley)
-Wilson Lab, Cornell U.