Byzantine tetrachords charted

At last, here is the reason I drew that tetrachord chart in the first
place -- to plot various authors' ideas of the tuning of the four
types of Byzantine chant tetrachords: "Enharmonic", Diatonic, Soft
Chromatic, Hard Chromatic.

I put "enharmonic" in scare-quotes because, as you will see, they bear
no resemblance whatsoever to the enharmonic tetrachord classification
of Aristoxenes and John Chalmers (and most everyone else). They are in
fact "improper diatonics" or "diatonics with a chromatic diesis" or
what Jacques Dudon calls "hyperdiatonics".

I have not yet found any clue as to how this completely different
meaning of "enharmonic" could have come about.

http://dkeenan.com/Music/TetrachordChart2.GIF

-- Dave Keenan