Subject: Re: Perception of rise/fall times From: Pierre Divenyi <pdivenyi(at)MARVA4.NCSC.MED.VA.GOV> Date: Thu, 10 May 2001 12:05:11 -0700One corollary observation (I owe it to my esteemed colleagues Eric Prame and Bob Efron): Slow (~1 to ~5 Hz) sinusoidal amplitude modulation produces one perceptual event per cycle (coinciding with the peak or the onsetof the positive ramp). Slow sinusoidal frequency modulation produces two. Pierre At 03:31 PM 5/10/01 -0400, Dennis P. Phillips, Ph.D. wrote: >Hi 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. > **************************************************************************** Pierre Divenyi, Ph.D. Speech and Hearing Research (151) V.A. Medical Center, Martinez, CA 94553, USA Phone: (925) 370-6745 Fax: (925) 228-5738 E-mail : pdivenyi(at)marva4.ebire.org ****************************************************************************