Chord · 9ths
Adim7/9 — A Diminished 7th / 9th
Adim7/9 is the A diminished 7th / 9th chord. It is built on the root A with minor 3rd (C), diminished 5th (E♭), major 6th (F♯) and major 9th (B) above it — the formula 1 ♭3 ♭5 6 9, sounding the notes A C E♭ F♯ B. On the piano it sits at A (octave 3) and above in the library's voicing; the same 5 notes in any octave are still Adim7/9.
- Root
- A
- Quality
- Diminished 7th / 9th
- Formula
- 1 ♭3 ♭5 6 9
- Notes
- A C E♭ F♯ B
On the keyboard
The notes of Adim7/9
| Degree | Note | Interval from the root | Pitch |
|---|---|---|---|
| 1 | A | root | A3 |
| ♭3 | C | minor 3rd | C4 |
| ♭5 | E♭ | diminished 5th | E♭4 |
| 6 | F♯ | major 6th | F♯4 |
| 9 | B | major 9th | B4 |
Other 9ths on A
Diminished 7th / 9th chords on every root
Part of the chord reference. See also the scales and the keys.