Ab7b9 guitar chord
The third voice from the top lowered an octave. The dropped voice becomes the bass, which is why a string is skipped.
- Tap a note to hear it
- Arrows change position
- Fingers, notes or intervals
- Play the chord
About Ab7b9 — drop 3 voicings
Ab7b9 is Ab, C, Eb, Gb and A — Ab9 with the ninth lowered a semitone.
It sounds dark and urgent. The flat ninth comes from the harmonic minor, so this is the V of a minor key rather than a major one.
Altered dominant — it points at a minor chord.
Ab7b9 notes and formula
| Ab | C | Eb | Gb | A |
|---|---|---|---|---|
| 1 | 3 | 5 | ♭7 | ♭9 |
Also written Ab7(b9), Ab7-9 or Ab7♭9. The same chord either way; which spelling you meet depends on who wrote the chart.
How to play Ab7b9
The same operation one voice further down: the third voice from the top falls an octave and becomes the bass.
That leaves a bigger hole under the top three notes, so a string gets skipped: the muted string in the middle is the shape, not a mistake.
Ab7b9 has 9 of them, on strings 5-3-2-1 and strings 6-4-3-2, from open position up to the 12th — every inversion the chord has: Ab in the bass, C in the bass, Gb in the bass and Bbb in the bass. The one to learn first is the Bbb shape at the nut.
5 of them sit on strings 5-3-2-1, so you can run the inversions up one set without changing strings — which is the whole reason to learn them as a family rather than as separate grips.
Five notes and four fingers, so something has to go. Keep C and Gb (they fix the quality) and A (what the symbol is about). Let Eb and Ab go, in that order — a perfect fifth says nothing the root has not, and in a band the bass has the root.
Play Ab7b9 as a shell — root, third and seventh — and the spare string takes the #11 (D), the b13 (Fb) or the 13 (F).
All 6 common shapes as fret numbers, lowest string first. Hover or tap one to see it drawn.
- x01112, open position, Bbb, 9th in the bass, top note Gb, barred
- 4342xx, 2nd fret, Ab, root position, top note A, all fretted
- xx4545, 4th fret, Gb, 3rd inversion, top note A, all fretted
- 464545, 4th fret, Ab, root position, top note A, barred
- xx6575, 5th fret, Ab, root position, top note A, all fretted
- x-11-10-11-10-11, 10th fret, Ab, root position, top note Eb, barred
How to use Ab7b9
Ab7b9 is a dominant with its tension raised, so it still points at Db — harder than a plain seventh does, because the altered tones sit a semitone from where they are going.
What to play over Ab7b9
Every note of Ab7b9 is in Ab half-whole diminished.
Chords near Ab7b9
Change one note of Ab7b9 and you have Ab7 (drop the flat ninth), Abalt (the fifth becomes the sharp fifth), Ab9 (the flat ninth becomes the ninth) or Ab7#9 (the flat ninth becomes the sharp ninth).
Ab7b9 is an altered chord — a dominant seventh with its fifth or ninth moved. Altered dominant chords on every root.
The common shapes and the derived voicings come from different places, and both are explained in how this site is built.