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Hey Laurie, nice set of links there..... At 09:17 PM 3/11/98 -0800, Laurie Hatch wrote: >****************************************************************** >Experimental Psychology Prof Chris Darwin's home page. >http://www.biols.susx.ac.uk/Home/Chris_Darwin/ >Go down to "Teaching", and click on "Lecture Notes". This is from a 2nd >year >course in hearing and perception. Very comprehensive. On this fellow's excellent page may be part of the answer, specifically here: http://www.biols.susx.ac.uk/Home/Chris_Darwin/Perception/Lecture_Notes/Heari ng3/hearing3.html#RTFToC6 where he discusses combination tones. a summary: In a person with healthy hearing, when two tones fairly close in frequency are played, a third tone can be heard. If the two input tones are F1 and F2, the third tone will be 2F1 - F2. This is called the cubic difference tone. This will probably not be harmonically related to either tone, and will therefore could sound very dissonant. He also notes that people suffering from hearing loss will not experience this. (he explains why, go read it.) By coincidence, I saw David Wessel tonight and asked him if he knew an answer, and he mentioned this same effect as a possibility. (he also noted there is much debate on the subject, and there are no hard answers.) He also noted that in older population groups, men usually suffer from considerably more hearing loss than women. (it's not clear if this is due to lifestyle, which may therefore be changing, or physiological differences.) So men will have more hearing loss than similarly aged women, and therefore will not experience this third tone effect as much as women will. So maybe that's part of the answer. As to why these dissonances result in discomfort, I have no idea..... kim ________________________________________________________ Kim Flint 408-752-9284 Mpact System Engineering kflint@chromatic.com Chromatic Research http://www.chromatic.com