Inverse | major third |
---|---|

Name | |

Other names | minor hexachord, hexachordon minus, lesser hexachord |

Abbreviation | m6 |

Size | |

Semitones | 8 |

Interval class | 4 |

Just interval | 8:5, 128:81, 11:7 |

Cents | |

12-Tone equal temperament | 800 |

Just intonation | 814, 792, 782 |

In Western classical music, a **minor sixth** is a musical interval encompassing six staff positions (see Interval number for more details), and is one of two commonly occurring sixths (the other one being the major sixth). 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 respectively).

In 12-tone equal temperament (12-ET), 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. It is equal to eight semitones, i.e. a ratio of 2^{8/12}:1 or simplified to 2^{2/3}:1 (about 1.587), or 800 cents.

In just intonation multiple definitions of a minor sixth can exist:

- In 3-limit tuning, i.e. Pythagorean tuning, the minor sixth is the ratio 128:81, or 792.18 cents,
^{[1]}i.e. 7.82 cents*flatter*than the 12-ET-minor sixth. This is denoted with a "-" (minus) sign (see figure).

- In 5-limit tuning, a minor sixth most often corresponds to a pitch ratio of 8:5 (
^{ⓘ}) or 814 cents;^{[2]}^{[3]}^{[4]}i.e. 13.7 cents*sharper*than the 12-ET-minor sixth.

- In 11-limit tuning, the 11:7 (
^{ⓘ})**undecimal minor sixth**is 782.49 cents.^{[5]}

The minor sixth is one of consonances of common practice music, along with the unison, octave, perfect fifth, major and minor thirds, major sixth and (sometimes) the perfect fourth. In the common practice period, sixths were considered interesting and dynamic consonances along with their inverses the thirds, but in medieval times they were considered dissonances unusable in a stable final sonority. In that period they were tuned to the *flatter* Pythagorean minor sixth of 128:81. In 5-limit just intonation, the minor sixth of 8:5 is classed as a consonance.

Any note will only appear in major scales from any of its minor sixth major scale notes (for example, C is the minor sixth note from E and E will only appear in C, D, E, F, G, A and B major scales).

Inverse | supermajor third |
---|---|

Name | |

Abbreviation | m6 |

Size | |

Semitones | 8 |

Interval class | 4 |

Just interval | 14:9^{[6]} or 63:40 |

Cents | |

12-Tone equal temperament | 800 |

24-Tone equal temperament | 750 |

Just intonation | 765 or 786 |

In addition, the **subminor sixth**, is a subminor interval which includes ratios such as 14:9 and 63:40.^{[7]} of 764.9 cents^{[8]}^{[9]} or 786.4 cents respectively.