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Re: multidimensional scaling of timbre


There are papers by Steven McAdams on this multidimentional scaling of timbre.

Pascale LIDJI, Ph.D.

BRAMS : Brain, music and sound 
Université de Montréal
+1 514 343 6111 # 3594

Unité de Recherches en Neurosciences Cognitives
Université Libre de Bruxelles
fax: +32-2-650-22-09 
e-mail : plidji@xxxxxxxxx
>I don't know of a paper on this topic, but here are some impressions.
>It is clear that people change their attention to dimensions depending  
>on the set. For example, if there are large pitch variations among the  
>stimuli, listeners' ratings are dominated by that dimension,  whereas  
>they attend more specifically to timbre dimensions if that pitch  
>variation is removed. On the face of it, it thus seems very plausible  
>that listeners can only attend to a small number of dimensions at a  
>time. It is certainly the case that higher dimensions in MDS solutions  
>become progressively less interpretable, which suggests that they may  
>just be modeling noise.
>That being said, it is hard to say whether this reveals an attentional  
>limitation or is a measurement issue with rating scales and the MDS  
>procedure. For example, I find that there is always much more  
>unaccounted variance when I am using real recordings than when I am  
>using a set (usually speech stimuli) that have been synthesized to  
>vary on only a small number of dimensions. For example, a set that has  
>been synthesized to be two dimensional will fit into a two-dimensional  
>solution far better than a set of natural recordings will fit into a  
>two-dimensional solution. I think that this indicates that listeners  
>are indeed sensitive to higher dimensions in the natural stimuli; the  
>unaccounted variance in such MDS experiments is not just noise.  
>However, the relative contribution of those dimensions begins to be  
>small enough to merge with the level of noise in the data, such that  
>they can no longer be modeled very well by MDS. That is, there is  
>usually enough gain to measure only a few of the most influential  
>dimensions that drove the rating-scale judgements.
>Best regards,
>Paul Iverson, Ph.D.
>UCL Division of Psychology & Language Sciences
>Chandler House
>2 Wakefield Street
>London WC1N 1PF
>> ----------------------------------------------------------------------
>> Date:    Sun, 19 Oct 2008 16:17:32 +0200
>> From:    Christian Kaernbach <auditorylist@xxxxxxxxxxxx>
>> Subject: multidimensional scaling of timbre
>> Dear list,
>> I seem to remember that one lesson from multidimensional scaling of
>> timbres was that the type of dimensions found depends strongly on the
>> selection of the stimuli. If my memory serves me right, the similarity
>> data would alway yield two- to three-dimensional spaces, regardless of
>> whether the stimuli were quite divers (all types of instruments of the
>> classical orchestra) or from a narrow subgroup (say, all woodwinds).  
>> In
>> other words, people seem to be able to manage two to three  
>> dimensions in
>> their cognitive space representing the entirety of the stimuli of a
>> certain experiment. Is that correct, and is there a reference  
>> referring
>> to this phenomenon?
>> Thanks in advance,
>> Chris
>> -- 
>> Christian Kaernbach
>> Kiel University
>> Germany
>> www.kaernbach.de