Minor sixth

minor sixth

Inverse	major third
Name
Other names	minor hexachord, hexachordon minus, lesser hexachord
Abbreviation	m6
Size
Semitones	8
Interval class	4
Just interval	8:5, 11:7, or 51:32
Cents
Equal temperament	800
24 equal temperament	800
Just intonation	814, 782, or 807

subminor sixth

Inverse	supermajor third
Name
Abbreviation	m6
Size
Semitones	8
Interval class	4
Just interval	14:9 or 63:40
Cents
Equal temperament	800
24 equal temperament	750
Just intonation	765 or 786

In classical music from Western culture, a sixth is a musical interval encompassing six staff positions (see Interval number for more details), and the minor sixth is one of two commonly occurring sixths. It is qualified as minor because it is the smaller of the two: the minor sixth spans eight semitones, the major sixth nine. For example, the interval from A to F is a minor sixth, as the note F lies eight semitones above A, and there are six staff positions from A to F. Diminished and augmented sixths span the same number of staff positions, but consist of a different number of semitones (seven and ten).

In equal temperament, the minor sixth is enharmonically equivalent to the augmented fifth. It occurs in first inversion major and dominant seventh chords and second inversion minor chords.

A minor sixth in just intonation most often corresponds to a pitch ratio of 8:5 or 1.6:1 ( play ) of 814 cents; in 12-tone equal temperament, a minor sixth is equal to eight semitones, a ratio of 2^2/3:1 (about 1.587), or 800 cents, 13.7 cents smaller. The ratios of both major and minor sixths are corresponding numbers of the Fibonacci sequence, 5 and 8 for a minor sixth and 3 and 5 for a major.

...
Wikipedia