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From: wilson@rocky.UUCP
Newsgroups: comp.sys.amiga,comp.sys.mac,comp.sys.atari.st,rec.music.makers,rec.music.synth
Subject: Re: Sonic Holography.
Message-ID: <800@rocky.STANFORD.EDU>
Date: Fri, 4-Dec-87 13:50:36 EST
Article-I.D.: rocky.800
Posted: Fri Dec  4 13:50:36 1987
Date-Received: Wed, 9-Dec-87 00:38:00 EST
References: <7536@eddie.MIT.EDU> <2476@gryphon.CTS.COM>
Reply-To: wilson@rocky.UUCP (Randy Wilson)
Organization: Stanford University Computer Science Department
Lines: 18
Xref: utgpu comp.sys.amiga:11084 comp.sys.mac:9405 comp.sys.atari.st:6179 rec.music.makers:1029 rec.music.synth:1851

>There was a display at the Ontario Science center, ohh, 12 years or so
>ago, about MC Escher, that had a ball bouncing "up" an ever increasing
>staircase, with this tone, going up in pitch.
>
>It went up in pitch for the 1/2 hour I stood there. :-)

The effect you are looking for is produced by having two tones, one an
octave above the other.  As they rise in unison, the lower tone slowly
becomes louder and the higher one becomes softer, until when they have
gone up an octave, the upper tone has completely died out and the
lower is where the upper started.  Then you bring in a weak tone where
the lower one started, and repeat.  The ear fools you into thinking it
is rising forever.  

It might work better with more than two tones at octave intervals, but
the idea is the same.

Randy