Subject: Re: MDS distances From: "Bruno L. Giordano" <bruno.giordano@xxxxxxxx> Date: Thu, 22 Jun 2006 16:00:43 -0400Dear Malcolm and list, I think the main problem in the classical MDS approach to the study of timbre is that dimensions were interpreted qualitatively, and not quantitatively. That's why, as you point out, it might be hard to understand what their MDS solutions mean. A quantitative studies of MDS dimensions are found at least starting from McAdams et al. (1995). This is a good approach, unless one forgets that it's of an exploratory nature. The confirmatory approach to the study of timbre dimensions has been instead pursued at least by Caclin et al. (2005). A good approach to the study of psychological domains of unknown dimensionality, as is the case of timbre, is thus to alternate between exploratory and confirmatory studies: before if timbre is indeed a function of perceptual dimensions (acoustical features) A and B (confirmatory approach) you might actually be willing to find which, among perceptual dimensions/acoustical features {A,B,C,D} explain your data (exploratory approach). Bruno McAdams S, Winsberg S, Donnadieu S, De Soete G, Krimphoff J. Perceptual scaling of synthesized musical timbres: common dimensions, specificities, and latent subject classes.Psychol Res. 1995;58(3):177-92. Caclin A, McAdams S, Smith BK, Winsberg S. Acoustic correlates of timbre space dimensions: a confirmatory study using synthetic tones. J Acoust Soc Am. 2005 Jul;118(1):471-82. ----- Original Message ----- From: "Malcolm Slaney" <malcolm@xxxxxxxx> To: <AUDITORY@xxxxxxxx> Sent: Thursday, June 22, 2006 3:36 PM Subject: Re: MDS distances > 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.. 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 > http://ccrma.stanford.edu/~hiroko/timbre/ > Sounds like Jim is doing something in between the two extremes. > > - Malcolm >