Definitions of tuning terms

© 1998 by Joseph L. Monzo

All definitions by Joe Monzo unless otherwise cited


commatic drift


From Paul Erlich, Yahoo tuning-list message 40367 (Tue Oct 29, 2002 2:49 pm):

    a shift is an *immediate* change in the pitch of a note, as the note is held or repeated from one harmony into another.

    a drift is an overall pitch change of the entire scale. its effect on the pitch of any note doesn't become evident until an entire "comma pump" chord progression has been traversed.

    for example, in the classic problem of rendering the I-vi-ii-V-I progression in strict JI, one either has a shift (the 2nd scale degree shifts from 10/9 in the ii chord to 9/8 in the V chord) and no drift, or a drift (the final I is lower by 80:81 than the initial I) and no shifts.


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