gtarr@afit.af.mil (Vax Headrm) (03/13/91)
Can someone please help me find a reference to or an individual who know anything about something called the discrete frequency paradox. Its supposed to be one of the few audio illusions. When played it sounds like a continually increasing frequency, but just goes on more or less forever. I think the guy who first wrote about it is named sheppard, but I'm not sure. Please help, either post or send response to gtarr@blackbird.afit.af.mil. Thanks.
georgiou@rex.cs.tulane.edu (George Georgiou) (03/13/91)
In article <1991Mar12.160801.23281@afit.af.mil> gtarr@afit.af.mil (Vax Headrm) writes: >Can someone please help me find a reference to or an >individual who know anything about something called >the discrete frequency paradox. Its supposed to be one >of the few audio illusions. When played it sounds like a >continually increasing frequency, but just goes on more or >less forever. I think the guy who first wrote about it >is named sheppard, but I'm not sure. Please help, >either post or send response to gtarr@blackbird.afit.af.mil. The reference you are looking for is: Shepard, Roger N. "Circularity judgments in relative pitch", Journal of the acoustical Society of America 36, Dec. 1964, pp. 2346-2353 Also, pp. 717-719, "Godel, Escher, Bach" by Douglas Hofstadter. George Georgiou georgiou@rex.cs.tulane.edu Computer Science Department +---------------------------+ Tulane University | Fiat Lux | New Orleans, LA 70118 +---------------------------+
mike@ushicom (Puddleglum Marshwiggle) (03/15/91)
What you've described in refered to as Shepard's Tones, named after AT&T Bell Labs psychologist Roger Shepard. The acoustical allusion he discovered exhibits the proprerty of circular pitch, that is, it sounds like the pitch is constantly rising, but it never goes anywhere. It is sometimes refered to as the "barber pole" effect. You can read about it on pg. 221 of Elements of Computer Music, by F. Richard Moore, which gives details on how to implement a shepard's tone generator. I couldn't find an "original reference". -- Michael Czeiszperger | Disclaimer: The above posting does not represent Yamaha Music Technologies | opinions or policies of Yamaha. mike@ymt.com |
minsky@media-lab.MEDIA.MIT.EDU (Marvin Minsky) (03/18/91)
In article <1991Mar14.174551.7759@ymt.com> mike@ushicom (Puddleglum Marshwiggle) writes: >What you've described in refered to as Shepard's Tones, named after >AT&T Bell Labs psychologist Roger Shepard. The acoustical allusion >he discovered exhibits the proprerty of circular pitch, that is, >it sounds like the pitch is constantly rising, but it never goes >anywhere. You can produce this effect on a piano, by playing a chromatic scale in four parallel octaves. Simply decrease the amplitude of the top not as it ascends the top octave, and increase the amplitude of the bottom note in the same way. The effect works because the combination of tones of the same pitch class over several octaves produces an unambiguous sense of pitch class but with ambiguous octave localization. Takes just a little practice.
usenet@cs.utk.edu (USENET News Poster) (03/19/91)
Seems to me that one J. S. Bach thought of this about 200 years ago, as was reported earlier in this BB, and also in Hofsteder's book: _Goedel,_Escher_&_Back_ -- well worth reading, IMHO. Phil Spelt From: sfp@mars.ornl.gov (Phil Spelt) Path: mars!sfp