Sevenths
A♭ diminished 7th chord
Symmetrical and very tense — every note is a minor 3rd apart.
A♭dim7 is the vii°7 chord in A minor.
- Notes
- A♭C♭E𝄫G𝄫
- Formula
- 1♭3♭5𝄫7
- Built from
- root · minor 3rd · diminished 5th · diminished 7th
How to play A♭dim7
About the A♭ diminished 7th chord
Playing it
On guitar, A♭dim7 has an open-position shape, 420101, using four fingers alongside the open strings.
On piano, A♭dim7 has one black key (A♭) and three white keys.
On ukulele the usual A♭dim7 shape is 1212, using four fingers.
Related chords
Take away the root and the other three notes form C♭dim (C♭ E𝄫 G𝄫) — so you can think of A♭dim7 as C♭dim with A♭ added underneath.
A♭dim7 is symmetrical — its notes are evenly spaced — so Ddim7, Fdim7 and Bdim7 contain exactly the same notes. There are only three different-sounding diminished 7th chords in all.
Move a single note and A♭dim7 becomes a different chord: drop the G𝄫 for A♭dim, raise E𝄫 to E♭ for A♭m6 and raise G𝄫 to G♭ for A♭m7♭5.
Where you’ll hear it
Notice the C♭ in A♭dim7 (A♭ C♭ E𝄫 G𝄫): each note of the chord takes its own letter (A–C–E–G), so the minor 3rd has to be written C♭ rather than B — the same key on a piano, spelled to fit the chord.
