December 11, 2010: Sixth Chords

Is there really such a thing as a sixth chord? Isn’t it really just a first inversion minor seventh? A C6, for example, is indeed an Am7/C. In western classical music theory, deriving from figured-bass terminology, what is called sixth chord is a chord in first inversion with the root voiced a major sixth above the bass note. If this is done with an Am triad the result will be a C6.

In the standard jazz repertoire a 6th chord is often used as the tonic chord of the composition because it appears to sound more static or resolved than a maj7. Play a II-V-I with the I being C6 (Dm7 / G7 / C6) and you can clearly hear that C is the root of the C6 chord and it does not appear to resolve to the A note (which would make it sound like an Am7/C).

Also a triad with a b6 added contains the identical notes as a first inversion maj7 chord with b6 that was added to the triad as root, i.e., Cm(add b6) = Abmaj7/C. Again, it is context that determines the root. If the sound of a minor triad is established, adding a b6 sounds like a m(add b6). A good example of this is Gary Peacock’s composition Vignette, which is both on Peacock’s album Tales of Another and on the Marcin Wasilewski Trio’s recording January. Both recordings are on the ECM Records label. There is a figure, repeated in different keys, with a minor triad with an added 2nd alternating with a m(add b6).

For clarity, if the 6th is flatted, I separate its root name from the flat symbol both parenthetically and with the term “add” as in C(add b6). Otherwise, if written Cb6, the improviser reading your chart may wonder, “Is it a C with a flatted sixth or a Cb with an added sixth?”

The listing below of sixth chords are arranged in the following manner:

Sixth chords (R356, etc.)
Symbol (C6, etc.)
Alternative Name depending on context (Am7/C, etc.)

Sixth Chords

R356
C6
Am7/C

R35b6
C(add b6)
Abmaj7#5/C

Rb356
Cm6
Am7b5/C
Rb35b6
Cm(add b6)
Abmaj7/C

R3b56
C6(b5)
F#m7b5/C

R3b5b6
C(add b6)b5
Ab+7/C, Ab7(b13)/C

Rb3b56
Cº7 - adding a 6th to a diminished triad is enharmonically identical to adding the diminished or bb7.
Aº7, Ebº7, F#º7

Rb3b5b6
Cº(add b6)
Ab7/C

With sixth chords, as with sevenths, 2 and 4 added are considered upper voices, Ex.: Cm6,9. Separate with a comma and if needed and again, use parentheses and the term "added" before a b6.

Next: Seventh Chords

Copyright © 1993-2010 Jack DeSalvo