source file: m1419.txt
Date: Mon, 18 May 1998 15:09:54 -0400

Subject: re: Tetrachords R Us

From: Rick Sanford <76122.2237@compuserve.com>

>>Here's a question which I was originally going to post privately to 
>>Chalmers,I've read about them for 
>>many years, and all of a sudden I realized that I don't know the 
>>fundamental reason behind their origin. Any thoughts are surely 
>>appreciated....thanks...Hstick

Neil: - I was waiting for John's succinct response myself, but I'll 
throw in that tetras operate as three-interval sets below an initial
tone.  Then began being joined as pairs, with a 'diazeuksis' separating, 
ending up with octave closure.  That's how I think of tetrachords.
John's articles and book are much more informed.  Joscelyn Godwin
also expresses their origins and simplicity very well in "harmonies
of heaven and earth"