Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!swrinde!zaphod.mps.ohio-state.edu!van-bc!cynic!curt
From: curt@cynic.wimsey.bc.ca (Curt Sampson)
Newsgroups: comp.music
Subject: Re: Timbre Perception and Orchestration
Message-ID: <1991Jun17.030934.499@cynic.wimsey.bc.ca>
Date: 17 Jun 91 03:09:34 GMT
References: <2118@anaxagoras.ils.nwu.edu>
Organization: Mad Artists' Technological Hangout
Lines: 50


Greg, I found your posting on the timbre perception research you've
been doing quite fascinating.

One thing that I am struck by, however, is the rather unquantified
nature of your descriptions of the timbre of various instruments.
For example, you call a claranet "dark" and an oboe "bright."

Not having seen any of the details of your research, it could well
be that you have quantified the timbres much better there than in
your summary.

If not, have you considered doing a Fourier analysis of the various
instruments and looking for correlations in the data from that?  My
ears tell me that as well as some instruments being darker or brighter
than others (that is, the average energy in the harmonics well above
the fundemental being higher or lower), different instruments often have very
different distributions of the energy within those upper harmonics.
Some instruments have a lot of energy concentrated in a few harmonics
(such as the oboe--or so my ears tell me :-)) and some have their
energy spread out more evenly over many harmonics (piano).  I suspect
that these differing distrubtions would make quite a difference in the
blending characteristics (and recognition characteristics, for that
matter).  

Another thing to look at would be the amount and distribution of
non-harmonic energy in an instrument's sound (the scraping of the bow,
and the like).

This might lead to some interesting expriments with computer-generated
tones of varying harmonic structure.  Synthesized tones created with a
decent additive synthesizer would give you far more flexibility when
testing blends of various kinds.  It would also provide a good control
in that one would expect that synthesized waveforms with characteristics
similar to acoustic instruments would generate similar results when
blended for listeners.  That is to say, if you have two waveforms with
a concentrated peak in the upper harmonics and they don't blend, but
two acoustic waveforms with a concentrated peak in the upper harmonics
do blend, there's obviously something else we should be looking for as
an important factor in blending.

So perhaps you could do a few experiments in this area too.  It's only
June, so I'm sure that you'll have plenty of time to research this
whole area and fit that into a brief Appendix in your dissertation.  :-)

cjs
-- 
Curt Sampson            | "This sound system comes to you with fuel injection.
curt@cynic.uucp         |  Toes tapping, the unthinking masses dance to a new
curt@cynic.wimsey.bc.ca |  tune...."		--Gary Clail