Subject: Perception of rise/fall times From: "Dennis P. Phillips, Ph.D." <ears(at)IS.DAL.CA> Date: Thu, 10 May 2001 15:31:08 -0400Hi Everyone: I'd like to thank all who responded to my recent question about asymmetries in the perceptual effects of rise and fall times. The responses were diverse, thoughtful, informative, and often pointed me to references which I had not previously found. This has been very helpful indeed. Again, many thanks. For folks who are interested, a "potted" summary would go something like this. Sounds with fast onsets and slow decays are judged as louder than their time-reversed analogs. Sinusoids with exponential onsets (ramped sinusoids) have a more tonal quality, and a less hollow, percussive one, than their time-reversed counterparts (damped sinusoids). Normal listeners are more sensitive to switching transients at the onset of a tone than to those at its offset. Thresholds for amplitude decrement detection are comparable to those for increment detection if the decrement is not too short in duration. Rise times (plucks and bows) are not perceived categorically. In general, these findings point to the perceptual importance of stimulus onsets (or increments). Below are a few of the references. All best wishes. Cheers, Dennis Irino, T. and Patterson, R.D. (1996) Temporal asymmetry in the auditory system. J. Acoust. Soc. Am., 99: 2316-2331. Miyasaka, E. (1980) Detectability of switching transients. NHK Laboratories Note No. 275. (abstract). Tokyo, Japan: NHK Science & Technical Research Labs. Oxenham, A.J. (1997) Increment and decrement detection in sinusoids as a measure of temporal resolution. J. Acoust. Soc. Am., 102: 1779-1790. Patterson, R.D. (1994a) The sound of a sinusoid: spectral models. J. Acoust. Soc. Am., 96: 1409-1418. Patterson, R.D. (1994b) The sound of a sinusoid: Time-interval models. J. Acoust. Soc. Am., 96: 1419-1428. Rosen, S.M. and Howell, P. (1981) Plucks and bows are not categorically perceived. Percept. Psychophys., 30: 156-168. Stecker, G.C. and Hafter, E.R. (2000) An effect of temporal asymmetry on loudness. J. Acoust. Soc. Am., 107: 3358-3368. ----------------------------------- Dennis P. Phillips, Ph.D. Hearing Research Laboratory Professor, Department of Psychology Dalhousie University Halifax, NS, Canada B3H 4J1 Phone: (902)494-2383 Fax: (902)494-6585 E-mail: ears(at)is.dal.ca -----------------------------------