Abdim7 guitar chord
Root, third and seventh: the guide tones fix the quality, so the fifth is dropped. That is what leaves a string free, so pick a tension to put on top.
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About Abdim7 — shell voicings
Abdim7 is Ab, Cb, D and F — Abdim with a diminished seventh stacked on top.
It sounds suspenseful and rootless. Three stacked minor thirds divide the octave evenly, so the same four notes spell four dim7 chords and the shape repeats every three frets.
Abdim7 notes and formula
| Ab | Cb | D | F |
|---|---|---|---|
| 1 | ♭3 | ♭5 | ♭♭7 |
Leading-tone or passing chord — it can resolve almost anywhere.
Also written Ab°7, Abo7 or Ab diminished 7. The same chord either way; which spelling you meet depends on who wrote the chart.
How to play Abdim7
Root, third and seventh. The third and seventh, the guide tones, are what make the chord major, minor or dominant, so the fifth can go: it says nothing the symbol needs.
Three notes means a spare string, which is the real point. Put a tension on it.
Abdim7 has 4 of them, on strings 6-4-3-2, strings 5-3-2-1 and the bottom four strings, from the 2nd fret up to the 10th — all in one inversion, so the bass note never moves. The one to learn first is the Ab shape at the 2nd fret.
Start with xx0101 — no barre and 2 open strings. 1 of the 7 shapes here sits in open position. 2 of the 7 need a barre. Together they cover the neck from the 1st fret to the 13th.
| Frets | Where | Bass | Top | Hand |
|---|---|---|---|---|
| xx0101 | open position | Ebb, 2nd inversion | F | 2 open strings |
| 4x3434 | 3rd fret | Ab, root position | Ab | barred |
| 456464 | 4th fret | Ab, root position | Ab | barred |
| xx6767 | 6th fret | Ab, root position | Cb | all fretted |
| x-x-9-10-9-10 | 9th fret | Cb, 1st inversion | D | all fretted |
| x-11-12-10-12-10 | 10th fret | Ab, root position | D | all fretted |
| x-x-12-13-12-13 | 12th fret | Ebb, 2nd inversion | F | all fretted |
The same notes rebuilt from scratch give 15 drop 2, 10 drop 3 and 6 open string voicings, each on its own page.
Tensions. A shell of Abdim7, root, third and seventh, leaves a string free, and the tones that belong over it are the 9 (Bb), the 11 (Db), the b13 (Fb) and the maj7 (G).
How to use Abdim7
A diminished seventh divides the octave evenly, so Abdim7 has no single root and no single destination: it can lead to Db or to A, and it is the same four notes either way.
What to play over Abdim7
Every note of Abdim7 is in Ab diminished and Ab half-whole diminished.
Chords near Abdim7
Change one note of Abdim7 and you have Abdim (drop the sixth), Abm6 (the flat fifth becomes a fifth), Abm7b5 (the sixth becomes a flat seventh) or AbmMaj7b5 (the sixth becomes a major seventh).
Abdim7 is a diminished chord — root, minor third, flat fifth. Diminished and half-diminished chords on every root.
On Abdim7’s sound and use this page follows Stefan Kostka, Dorothy Payne & Byron Almén, Tonal Harmony (McGraw-Hill, 8th ed., 2018). The shapes and the derived voicings come from different places, and both are explained in where the chords and the theory come from.