Diaschisma
Interval information |
reduced subharmonic
2048/2025, the diaschisma, an interval of 19.553 cents, is the difference between four perfect fifths plus two major thirds and three octaves. Tempering it out leads to the diaschismic family of temperaments. It may also be defined as the difference between a Pythagorean minor seventh (16/9) and a just augmented sixth (225/128), as the difference between two classic diatonic semitones (16/15) and the major whole tone (9/8), that is, (9/8)/(16/15)2, or as the difference between the 5-limit tritone 45/32 and its enharmonic equivalent 64/45.
Example
parizek1 A comma pump progression that assumes that the diaschisma is tempered out (i.e. equates two notes that are separated by a diaschisma).