Re: multidimensional scaling of timbre (Pascale Lidji )

Subject: Re: multidimensional scaling of timbre
From:    Pascale Lidji  <plidji@xxxxxxxx>
Date:    Mon, 20 Oct 2008 12:39:43 +0200

Hi, 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 +32-2-650-26-40 fax: +32-2-650-22-09 e-mail : plidji@xxxxxxxx >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 > >Paul Iverson, Ph.D. >UCL Division of Psychology & Language Sciences >Chandler House >2 Wakefield Street >London WC1N 1PF >UK > > > > >> ---------------------------------------------------------------------- >> >> Date: Sun, 19 Oct 2008 16:17:32 +0200 >> From: Christian Kaernbach <auditorylist@xxxxxxxx> >> 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 >> > >

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