Tonality flux
Tonality flux is
microtonal context from notes moving from one chord to another by tiny increments of voice leading. For instance, within a major third G-B, there can be a minor third G to B, such that in moving from one to the other each line shifts less than a half-step. Within a just intonation scale, this could be represented (, indicates an approximate quarter-tone sharp,
an approximate quarter-tone flat) by
Note name | ratio | cents | interval name |
---|---|---|---|
G | 1/1 | 0 | Just major third |
B | 5/4 | 386 |
moving to
Note name | ratio | cents | interval name | name | ratio | cents |
---|---|---|---|---|---|---|
G | 55/54 | 32 | Just minor third | G – B | 6/5 | 316 |
B | 11/9
|
347 |
like so:
Note name |
ratio | cents | name | ratio | cents |
---|---|---|---|---|---|
B | 5/4 | 386 | |||
B♭ | 11/9 | 347 | |||
G | 55/54 | 32 | |||
G | 1/1 | 0 |
One voice slides down from 386 cents to 347, the other slides up from 0 cents to 32, yet the harmonic shift can be dramatic. The best-known example of tonality flux, and one of the two Partch uses as illustration, is the beginning of his composition The Letter, in which the
Ben Johnston's pitch notation
):
In this notation, which assumes G as the
7/4
(969 cents). Notice that while the outer notes ascend from the first chord to the second, the middle note descends. Such subtle movements were among the attractions that Partch found in an expanded just intonation of more than 12 pitches per octave. Tonality flux is a special instance of the principle of parsimonious (most direct) voice leading.
See also
- enharmonic progression
- Identity (tuning)
- Tonality diamond
References
- ISBN 0-306-80106-X.