Hi Alberto, I don't believe that there are any "official" categories for classifying real world sounds. In my opinion, Gaver's taxonomy of environmental sounds, while clearly not perfect, is still the best that we have for classifying sounds in general. At least it is a great starting point. As you wrote in your email the problem of classification is very complex, and this is one reason why you have not been able to find much information about it. Real world sounds are produced by a great variety of different sound sources which cannot be unambiguously classified either. People have tried to find some kind of an underlying perceptual structure of environmental sounds (e.g., Ballas, 1993; Marcell et al., Gygi, 2001), but that has not revealed any clearcut categories. Which is not to say that there is no category structure, but rather that the categories do not reveal themselves very easily and unambiguously with the analysis methods we are using. My preferred analogy for the perceptual organization of real world sounds would be that of the lexicon where individual items can be classified based on acoustics/phonology, and also based on the ecological significance/semantics/meaning. Of course, this analogy is not perfect, and I offer it just as one way to think about the problem. For one, for most environmental sounds the relationship between their semantics and acoustics is not as arbitrary as it is for words. If I understood you correctly, and your goal is synthesizing musically useful noises (possibly based on some real world sounds) then rather than trying to come up with a general all-encompassing classification of real world sounds you may have more success figuring out specific types of noises/sounds that maybe interesting for your application. Or, you can try to find a way to represent different types of sounds in a smaller subset. Best regards, Valeriy ------------------------------------------------------------- Valeriy Shafiro Communication Disorders and Sciences Rush University Medical Center Chicago, IL office (312) 942 - 3298 lab (312) 942 - 3316 email: email@example.com Refs: Ballas, J.A. (1993). Common factors in the identification of an assortment of brief everyday sounds. Journal of Experimental Psychology: Human Perception and Performance, 19 (2), 250-267. Gygi, B. (2001). Factors in the Identification of Environmental Sounds, Unpublished doctoral dissertation, Indiana University, Bloomington, Indiana. Retrieved 02/20/02 from http://www.indiana.edu/~k300bg/dissall.pdf Marcell, M.M., Borella, D., Greene, M., Kerr, E. & Rogers, S. (2000). Confrontation naming of environmental sounds. Journal of Clinical and Experimental Neuropsychology, 22(6), 830-864.