Ab9 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.
- Tap a note to hear it
- Arrows change position
- Fingers, notes or intervals
- Play the chord
About Ab9 — shell voicings
Ab9 is Ab, C, Eb, Gb and Bb — Ab7 with the ninth stacked on top.
It sounds bright and full, still clearly pulling. The ninth adds height without softening the tritone underneath it, which is why funk and soul comp on this rather than on a plain 7.
Ab9 notes and formula
| Ab | C | Eb | Gb | Bb |
|---|---|---|---|---|
| 1 | 3 | 5 | ♭7 | 9 |
Dominant — the same pull as a 7, with more colour.
Also written Abdom9 or Ab dominant 9. The same chord either way; which spelling you meet depends on who wrote the chart.
How to play Ab9
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.
Ab9 has 3 of them, on the bottom four strings, the top four strings and the middle four strings, from the 3rd 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 3rd fret, which is the easiest grip here.
Start with 4343xx — no barre and low, at the 3rd fret. None of the shapes for Ab9 uses an open string, so every one of them is movable; the lowest sits at the 1st fret. 5 of the 8 need a barre. Together they cover the neck from the 1st fret to the 11th.
| Frets | Where | Bass | Top | Hand |
|---|---|---|---|---|
| x11112 | 1st fret | Bb, 9th in the bass | Gb | barred |
| 411312 | 1st fret | Ab, root position | Gb | barred |
| 4343xx | 3rd fret | Ab, root position | Bb | all fretted |
| 464346 | 3rd fret | Ab, root position | Bb | barred |
| 464546 | 4th fret | Ab, root position | Bb | barred |
| xx6576 | 5th fret | Ab, root position | Bb | all fretted |
| 8x6876 | 6th fret | C, 1st inversion | Bb | all fretted |
| x-11-10-11-11-11 | 10th fret | Ab, root position | Eb | barred |
The same notes rebuilt from scratch give 12 drop 2, 9 drop 3, 13 rootless and 2 open string voicings, each on its own page.
Tensions. A shell of Ab9, root, third and seventh, leaves a string free, and the tones that belong over it are the #11 (D), the b13 (Fb) and the 13 (F).
How to use Ab9
Ab9 is the V of Db, and that is where it goes if it goes anywhere: the third and the flat seventh are a tritone apart, and both resolve by a semitone into Db.
In which keys. Every note of Ab9 belongs to C# major (the V, the dominant) and Bb minor (the ♭VII).
What to play over Ab9
Every note of Ab9 is in Ab mixolydian and Ab lydian dominant.
Chords near Ab9
Change one note of Ab9 and you have Abmaj9 (the flat seventh becomes a major seventh), Abm9 (the major third becomes a minor third), Abadd9 (drop the flat seventh), Ab69 (the flat seventh becomes a sixth), Ab7 (drop the ninth) or Ab9b5 (the fifth becomes a flat fifth).
Ab9 is a dominant chord — root, major third, fifth, minor seventh. Dominant seventh chords on every root.
On Ab9’s sound and use this page follows Mark Levine, The Jazz Theory Book (Sher Music, 1995). The shapes and the derived voicings come from different places, and both are explained in where the chords and the theory come from.