Minor Sixth Chord

Use the formula 1-flat 3-5-6:

The m describes the triad. The unaltered 6 means a major sixth above the root.

Chord symbols measure the added degree from the root.

A major sixth above C is A. A flat is a minor sixth above C and is not what Cm6 specifies.

Do not confuse the chord name minor sixth with the interval minor sixth. In Cm6, minor describes the triad and the sixth remains major.

Start with C minor, C-E flat-G, and add A.

Transpose the formula. Fm6 is F-A flat-C-D; Am6 is A-C-E-F sharp.

Build from scale degrees so the major sixth is correct in every key.

C Dorian contains C-E flat-G-A and supports Cm6.

C jazz melodic minor also contains those chord tones, with B natural instead of Dorian's B flat. The chord alone does not specify the seventh degree.

C natural minor uses A flat, so A natural acts as a chromatic or borrowed tone in that context.

They share pitch classes:

C in the bass and a C-minor tonic context favor Cm6. A in the bass and motion toward D7 or another target may favor Am7 flat 5.

Spell and name the chord according to its root and function.

Cm6 uses A. Cm7 uses B flat.

Both retain C-E flat-G. The two added notes are a semitone apart.

Cm6 often supports Dorian or melodic-minor color. Cm7 fits Dorian, Aeolian and other minor-mode contexts depending on the remaining scale degrees.

Hold C-E flat-G and move an upper voice C-B-B flat-A.

The resulting sonorities are Cm with an octave root, CmMaj7, Cm7 and Cm6.

The chromatic line supplies continuity while the minor triad remains fixed.

Minor-sixth tonic chords appear in jazz, bossa nova, tango, film music and arranged popular music.

They can close a minor-key phrase, support a Dorian tonic or form one stage of chromatic voice leading.

Check whether A remains stable or continues to another note before assigning its role.

Cm6 has four bass positions using C, E flat, G or A.

With A in the bass, the structure strongly resembles Am7 flat 5. The progression decides whether that is an inversion or a new root interpretation.

Keep E flat and A clear because they define minor quality and the sixth.

Build Cm, Cm7 and Cm6 while holding C, E flat and G.

Play Cm-F to hear A inside Dorian harmony. Then play CmMaj7-Cm7-Cm6 and follow B-B-flat-A.

Put A in the bass and continue to D7-Gm to test the Am7-flat-5 interpretation.