Adim7
A Diminished 7th — perfectly symmetrical stacked minor thirds — the ultimate passing chord, able to resolve almost anywhere.
The keys
A – C – E♭ – G♭
What's inside Adim7
| Note | Interval from root | Degree |
|---|---|---|
| A | Root | 1 |
| C | Minor 3rd | b3 |
| E♭ | Diminished 5th | b5 |
| G♭ | Diminished 7th | bb7 |
Inversions
| Position | Keys (low → high) |
|---|---|
| Root position | A4 – C5 – E♭5 – G♭5 |
| 1st inversion | C5 – E♭5 – G♭5 – A5 |
| 2nd inversion | E♭5 – G♭5 – A5 – C6 |
| 3rd inversion | G♭5 – A5 – C6 – E♭6 |
A working voicing
Split the chord between two hands the way working players do — a solid shell low down, the colour tones up top:
| Hand | Keys |
|---|---|
| Left (shell) | A2 – G♭3 |
| Right (colour) | C5 – E♭5 |
Where Adim7 lives
As the ii chord
Adim7 → D7 → Gmaj7
Minor-family sevenths live on the ii — this is the move they were born for.
Stepwise colour
A → Adim7 → Bm7
Used as a passing colour between neighbouring chords.
Put Adim7 under your fingers
Hear every voicing, see the keys light up, and drill it in the interactive Chord & Voicing Lab.
Open the Chord & Voicing Lab →