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From: dar@telesoft.UUCP
Newsgroups: comp.sys.amiga,comp.sys.mac,comp.sys.atari.st,rec.music.makers,rec.music.synth
Subject: Re: Sonic Holography. (ever increasing tone)
Message-ID: <130@telesoft.UUCP>
Date: Fri, 4-Dec-87 16:45:44 EST
Article-I.D.: telesoft.130
Posted: Fri Dec  4 16:45:44 1987
Date-Received: Wed, 9-Dec-87 20:56:06 EST
References: <7536@eddie.MIT.EDU> <2476@gryphon.CTS.COM>
Organization: TeleSoft Inc., San Diego, CA
Lines: 17
Xref: utgpu comp.sys.amiga:11107 comp.sys.mac:9428 comp.sys.atari.st:6191 rec.music.makers:1031 rec.music.synth:1857
Summary: ever increasing (Sheppard's) tone


The classic tone which constantly rises in pitch is called a Sheppard's
tone (spelling?).  It is very well know in psycho-acoustic circles.  It is
fairly easy to compute the samples for on a computer (e.g. something
running CMusic), but would probably be tricky on a MIDI synth - largely a
matter of blending amplitudes/spectra correctly.

Diana Deutch, of the Univ. of Calif. San Diego, played Sheppard's tones
and other interesting audible illusions at an Audio Engineering Society
(AES) convention in Los Angeles (perhaps '82?).  Also, Roderer's "The
Physics and Psycoacoustics of Musical Sound" (or something like that - the
bibliography part of my brain is off-line at the moment) probably
discusses it in detail.  Any good university library should have MANY
references.

-David
sdcsva!telesoft!dar, dar@sdcsvax.(uucp,arpa,com,edu)