Gammic comma
Interval information |
(Shannon, [math]\sqrt{nd}[/math])
The gammic comma (monzo: [-29 -11 20⟩) is a small 5-limit comma with a size of 4.769 cents. It is the difference between nine just major thirds (5/4) and eleven just minor thirds (6/5), that is, (6/5)11/(5/4)9. This can also be written as (25/24)10/(3/2), that is, the difference between a stack of ten classic chromatic semitones and a perfect fifth; it is part of a series of Don Page commas between adjacent superparticulars, following the escapade comma, which follows the Pythagorean comma; and also the difference between the valentine comma and sycamore comma. It is additionally the difference between three kleismas (15625/15552) and a diaschisma (2048/2025).
Temperaments
Temperaments in the gammic family temper out this comma.
Etymology
The gammic comma is named after the Carlos Gamma scale, nearly identical to 20edf, which the gammic temperament generates.