Minor 6th
m6
0 - 3 - 7 - 9Minor + major 6th
About Minor 6th
A minor sixth chord is a four-note chord built from a minor triad plus a major sixth — in C that is C, E♭, G and A, written Cm6. The sixth is major even though the chord is minor, and that single raised note is what separates the sound from an ordinary minor chord: it is bright where the rest of the chord is dark.
Notes and formula
The formula is 1 – ♭3 – 5 – 6, or 0 – 3 – 7 – 9 in semitones from the root. The A is a major sixth above C, not the minor sixth that a natural minor scale would supply.
That raised sixth is why the chord belongs to Dorian rather than to Aeolian. Play Cm6 in a piece that has been using A♭ and the chord will sound like a modulation; play it in a Dorian context and it will sound like the tonic it is.
How to play it
On guitar a workable form is x3121x, sounding C–E♭–A–C. The fifth is left out, which costs nothing — as in every four-note chord, the third and the added note carry the identity.
On piano the chord is C–E♭–G–A, and it tolerates close voicing better than most: the sixth sits a whole tone below the octave and creates no cluster.
The chord it shares its notes with
The four notes of a minor sixth, spelled from A, are A–C–E♭–G, a half-diminished seventh. So Cm6 and Am7♭5 are one collection heard two ways, and jazz players use the identity in both directions: a minor sixth shape is the quickest route to a half-diminished chord, and vice versa.
It also shares three notes with a dominant seventh a tritone away, which is the theoretical basis for using a minor sixth as a substitute in a minor cadence.
What it does
Its oldest role is the fourth degree of a minor key — the iv6 that appears in cadences throughout classical music, where the sixth is a raised note leading upward. Its modern role is the tonic of a Dorian piece, where it does not lead anywhere at all.
In minor-key jazz it is the standard final chord. A minor seventh at the end of a minor tune sounds unfinished; a minor sixth sounds closed, and that is why arrangers reach for it in the last bar.
Minor sixth or minor seventh
Cm6 is C–E♭–G–A, Cm7 is C–E♭–G–B♭. One note apart, and the difference in behaviour is large: the seventh version is open and loops naturally, the sixth version is closed and ends.
The two are not usually interchangeable in a chart. Substituting a sixth for a seventh in the middle of a progression makes the phrase sound like it has arrived early, which is occasionally the point and more often a mistake.
Scales that contain it
Dorian fits without alteration and is the standard choice — the raised sixth in the scale is the raised sixth in the chord. Melodic minor fits too and adds a leading tone, which is what classical writing uses over the iv6.
Aeolian does not fit. Its flattened sixth is the chord's sixth lowered by a semitone, and the clash is direct, which makes this one of the few common chords that rules out the natural minor scale outright.
Frequently asked questions
What notes are in a Cm6 chord?
C, E♭, G and A — a minor triad with a major sixth. On guitar a common form is x3121x, which omits the fifth.
Why is the sixth major in a minor chord?
Because the chord comes from the Dorian mode, where the sixth degree is raised. A minor triad with a minor sixth is a different chord altogether and is normally written as an inversion of a major chord instead.
Is Cm6 the same as Am7♭5?
The same four notes with a different root. Cm6 is a resting minor chord; Am7♭5 is the ii of a minor ii–V–i. What decides is the bass note and what the progression does next.