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Re: Amplitude and pitch of sound waves



At 01:41 11/29/99 -0500, you wrote:
////
By the way, the piano waveform doesn't look exactly periodic on an
oscilloscope because "it's alive." The waveform is very dynamic, minor
beating coming and going, unison strings interacting with each other as
energy is coupled back and forth between the strings. But overall it's
basically periodic.///
Michael D. Edmiston

That was a very fine insight and commentary from Michael on Leigh's
scholarly insight into stretching of piano high octaves.
(I got a sense that the low piano octaves could also recieve some
attention from the tuner - shrinking? - but nobody made this explicit.)

Anyway, as someone who nobody would describe as a physics nerd, I
mention that one does not need to appeal to PhD musicians for
definitions of periodicity.
There is an easily accessible measure called autocorrelation,
which puts a number to this very property.


brian whatcott <inet@intellisys.net>
Altus OK