Abmaj7b5 guitar chord
A close-position chord with the second voice from the top lowered an octave. Sits on four adjacent strings.
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- Fingers, notes or intervals
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About Abmaj7b5 — drop 2 voicings
Abmaj7b5 is Ab, C, D and G — Abmaj7 with the fifth lowered a semitone.
It sounds hollow and hard to place. Far more often met spelled the other way round, as a ♯11 over a chord that kept its fifth.
Abmaj7b5 notes and formula
| Ab | C | D | G |
|---|---|---|---|
| 1 | 3 | ♭5 | 7 |
Coloured tonic — rare, and unstable for a major chord.
Also written AbM7b5, AbΔ7b5 or Abmaj7(b5). The same chord either way; which spelling you meet depends on who wrote the chart.
How to play Abmaj7b5
Take the four notes stacked as close together as they go, then drop the second voice from the top an octave. The gap it opens is what makes the chord sound like a chord rather than a cluster.
It lands on four adjacent strings, which is why it is the workhorse voicing on guitar.
Abmaj7b5 has 14 of them, on the top four strings, the bottom four strings and the middle four strings, from open position up to the 12th — every inversion the chord has: Ab in the bass, C in the bass, Ebb in the bass and G in the bass. The one to learn first is the Ebb shape at the nut, which is the easiest grip here.
5 of them sit on the top four strings, 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.
Start with xx6788 — no barre. None of the shapes for Abmaj7b5 uses an open string, so every one of them is movable; the lowest sits at the 3rd fret. 2 of the 5 need a barre. Together they cover the neck from the 3rd fret to the 13th.
| Frets | Where | Bass | Top | Hand |
|---|---|---|---|---|
| 435533 | 3rd fret | Ab, root position | G | barred |
| 4555x4 | 4th fret | Ab, root position | Ab | barred |
| xx6788 | 6th fret | Ab, root position | C | all fretted |
| x-11-10-12-13-10 | 10th fret | Ab, root position | D | all fretted |
| x-11-12-12-13-x | 11th fret | Ab, root position | C | all fretted |
The same notes rebuilt from scratch give 5 shell, 10 drop 3 and 2 open string voicings, each on its own page.
Tensions. A shell of Abmaj7b5, root, third and seventh, leaves a string free, and the tones that belong over it are the 9 (Bb) and the 13 (F).
How to use Abmaj7b5
How you get to it. The turn that lands on Abmaj7b5 is Bbm7 to Eb7 — the ii and the V of Ab — and Eb7 shares its third and seventh with Bbm7, so the hand barely moves between them.
In which keys. Every note of Abmaj7b5 belongs to C minor (the ♭VI) and Eb major (the IV, the subdominant).
What to play over Abmaj7b5
Every note of Abmaj7b5 is in Ab lydian.
Chords near Abmaj7b5
Change one note of Abmaj7b5 and you have Abmaj7 (the flat fifth becomes a fifth), Abmaj7#5 (the flat fifth becomes a sharp fifth), AbmMaj7b5 (the major third becomes a minor third) or Ab7b5 (the major seventh becomes a flat seventh).
Abmaj7b5 is a major chord — root, major third, fifth. Major chords on every root.
On Abmaj7b5’s sound and use this page follows Robert Rawlins & Nor Eddine Bahha, Jazzology (Hal Leonard, 2005). The shapes and the derived voicings come from different places, and both are explained in where the chords and the theory come from.