Minor Sixth

Count the letter names from C to A flat: C, D, E, F, G, A. That makes it a sixth.

The distance covers eight semitones, which makes the sixth minor. C to A covers nine and is a major sixth.

C to G sharp uses the same piano keys as C to A flat in equal temperament, but it spans five letter names. It is therefore an augmented fifth, not a minor sixth.

Move the lower C of C-A flat above A flat. The result is A flat-C, a major third.

Under inversion, interval numbers add to nine: 6 plus 3. Minor quality becomes major.

This gives you a practical check. If the lower and upper pitch classes form a major third when reversed, the original interval was a minor sixth.

Natural minor contains a minor sixth above its tonic. In A natural minor, degree 6 is F, so A-F spans eight semitones.

Phrygian and aeolian use a minor sixth. Dorian and ascending melodic minor use a major sixth instead.

In C major, E up to the next C is a minor sixth. An interval can appear between scale degrees even when it is not measured from the tonic.

A major triad in first inversion can place a minor sixth between its bass and top note.

C major is C-E-G. Put E in the bass and arrange E-G-C. E to the upper C is a minor sixth.

The chord remains C major because C is still the root. The interval is measured from the sounding bass E, while chord identity is measured from the harmonic root C.

Wide voicings also create minor sixths between inner voices. Identify the two notes first, then decide how their interval functions inside the full chord.

It can sound the same on a piano, but spelling and function differ.

C-A flat is a minor sixth. The letter count reaches A.

C-G sharp is an augmented fifth. The letter count reaches G, and G sharp often functions as a raised fifth in C augmented.

In C augmented, G sharp may rise to A. Written as A flat in another context, the same piano key may fall to G. Notation records that voice-leading intention.

No. In A harmonic minor, F to G sharp spans three semitones but uses the letters F and G. It is an augmented second.

Those piano keys could be respelled F-A flat as a minor third, but neither spelling makes them a minor sixth.

Semitone count alone is insufficient. Count letter names to determine the interval number, then use semitones to determine its quality.

An ascending minor sixth moves eight semitones upward, such as C4 to A flat4. A descending version reverses the direction.

Practice it against a root drone first. Then remove the drone and transpose the pair so you recognize the distance rather than one starting pitch.

Compare three neighboring intervals from C: G is a perfect fifth, A flat a minor sixth and A a major sixth. The one-semitone boundaries become clearer when everything else stays fixed.

The perfect fifth is one semitone narrower. The major sixth is one semitone wider.

An augmented fifth has the same equal-tempered keyboard distance but a different letter count and harmonic function.

A descending major third uses the same pitch classes as an ascending minor sixth after octave displacement. Direction and register determine which interval is actually sounding.

A pure minor sixth can use the ratio 8:5, about 814 cents.

Equal temperament uses eight semitones, exactly 800 cents. The piano interval is therefore about fourteen cents narrower than the 8:5 version.

Flexible-pitch ensembles may adjust sustained notes according to chord function. The written name remains minor sixth while the exact tuning varies.