525/512
| Interval information |
Avicenna's enharmonic diesis
reduced harmonic
525/512, the avicennma, also known as Avicenna's enharmonic diesis, is a medium 7-limit comma measuring about 43.4 cents. It is the difference between 64/63 and 25/24, or between 32/25 and 21/16.
In the 11-limit, it factors into (45/44)⋅(385/384), and in the 2.3.5.7.13 subgroup, (65/64)⋅(105/104).
Temperaments
Tempering out this comma equates 64/63 with 25/24 and leads to the avicennmic temperament. Because it flattens 3/2 and 5/4, it is a natural choice to further temper out 81/80, resulting in flattone temperament.
See Avicennmic temperaments for a collection of rank-2 temperaments where it is tempered out.