It IS known by some mathematicians. See p.257 of The Book of Numbers. But, lack-a-day, we define it as `the difference between 7 fifths and 4 octaves' whereas it should be `12 and 7'. R. On Mon, 27 Oct 2003, Thane Plambeck wrote:
The frequency ratio of 3^12 divided by 2^19 = 1.0136... is called the Pythagorean Comma, at least by music people.
That's a constant name that doesn't seem to be known much to math people, not that it should be, I suppose. Anyway, if you up 12 pure fifths from a note then go down 7 octaves, the resulting tone is little bit higher than the one you started out with and the difference is the pythagorean comma. I don't know how the shepard thing works but it might be related
Thane Plambeck 650 321 4884 office 650 323 4928 fax http://www.qxmail.com/ehome.htm
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