Definitions of tuning terms

© 1998 by Joseph L. Monzo

All definitions by Joe Monzo unless otherwise cited


commatic drift


    A major problem with the performance of music in just-intonation, especially on unaccompanied non-fixed-pitched instruments (i.e., string quartet or a capella vocals), is the possibility of the overall tonality drifting in commatic increments, usually downward ('flat').

    The problem occurs mainly in diatonic music, and because of the ambiguity of the 2nd degree of the 'major' scale. This degree normally needs to be tuned to either of two ratios in order to fit harmonically all of the chords in the scale: as a 9:8 to fit the V ('dominant') chord and its relatives, and as a 10:9 to fit the ii ('supertonic') and IV ('subdominant') chords and their relatives.

    [from Joe Monzo, JustMusic: A New Harmony]


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