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Just a brief aside to this discussion, to point out that MDS of timbre
has also served other purposes, apart from the original more narrowly
defined idea of coming up with dimensions to characterize sounds.
For instance, two such applications from my own lab were aimed at (1)
using timbre MDS to probe the perceptual deficits of patients with
lesions of auditory brain regions, and (2) using timbre MDS as a means
of ensuring that normal listeners who were asked to imagine sounds
during a neuroimaging study were indeed following the instructions, and
were succesful at creating internal representations of the target
sounds. In both cases, the MDS solutions themselves were less important
(in terms of interpreting the dimensions, for instance) than was
exploiting the paradigm as a means of probing perception.
So, yes, MDS experiments are still carried out, but sometimes for
reasons quite different than the psychoacoustics community might realize!
1. Samson, S., Zatorre, R.J. and Ramsay, J. (2002) Deficits in musical
timbre perception after unilateral temporal-lobe lesion revealed with
multidimensional scaling. Brain, 125, 511-523.
2. Halpern, A.R., Zatorre, R.J., Bouffard, M., Johnson, J.A. (2004)
Behavioral and neural correlates of perceived and imagined timbre.
Neuropsychologia, 42, 1281-1292.
David Wessel wrote:
On Jun 22, 2006, at 12:36 PM, Malcolm Slaney wrote:
On Jun 21, 2006, at 2:54 AM, Olivier Tache wrote:
I have read a number of "classical" papers about MDS and auditory
dissimilarity (by Gordon&Grey, Grey&Moorer, Wessel) (and was wondering
if such experiments were still carried out).
I think the Gray/Wessel approach has failed..
Failed at what? Malcolm, I think you have missed the point. My
original goal in the early 70's was to develop representations of
musical material that would help me reason about the composition of
timbre sequences known as klangfarbenmelodies. In one of my early
papers ( http://xenakis.ircam.fr/articles/textes/Wessel78a/ ), I
demonstrate that one can obtain interpretable geometric representations
of musically useful timbres and that such "timbre spaces" can be used
to make predictions about the behavior of timbre sequences. Hardly a
failure! Grey and Gordon demonstrated how such MDS spaces can be used
to make interesting timbral interpolations or hybrid instrument
sounds. Recently, I've taken a new look at the timbre space
representations obtained by myself, Grey, McAdams, Wedin and Goude and
am struck by how well Les Atlas's Modulation Spectrum describes what is
a common feature of many of the 2-D spaces wherein one of the
dimensions is related to the spectral envelope and the other the
I have no objection to your and Terasawa's approach of testing a pre-
ordained model such as one based on MFCC's. However, such tests should
be carried out in a direct manner as suggested by Krantz and Tversky in
their work on the foundations of the geometric representation of
perceptual data (see Suppes, Krantz, Luce, & Tversky's Foundations of
Measurement Vol 2). I doubt that MFCC's will pass the straightforward
qualitative test of "interdimensional additivity" essential to a
"The spectrum is not an interesting steady date." she said as I was
it's too hard to figure out what the results mean. (Just trying to be
blunt to get your attention. ;-) You start with convenient sounds,
measure perception and then try to figure out what the MDS dimensions
mean. That hasn't worked. I think that is why people have not been
pushing on it very hard lately.
Hiroko Terasawa and I have been taking an opposite approach. We're
*starting* with the dimensions, synthesizing sounds and then measuring
the stress between human perception and the pre-ordained model.
Several papers describing our initial results are online at
Sounds like Jim is doing something in between the two extremes.
Robert J. Zatorre, Ph.D.
Montreal Neurological Institute
3801 University St.
Montreal, QC Canada H3A 2B4
web site: www.zlab.mcgill.ca