About Ab7sus4 — drop 2 voicings
Ab7sus4 is Ab, Db, Eb and Gb — Ab7 with the third replaced by the fourth.
It sounds leaning rather than shoving. It keeps the flat seventh’s pull and loses the tritone, so it moves without making a hard cadence.
Ab7sus4 notes and formula
| Ab | Db | Eb | Gb |
|---|---|---|---|
| 1 | 4 | 5 | ♭7 |
Dominant — it points a fifth down, but softly.
Also written Ab7sus or Ab dominant 7 sus 4. The same chord either way; which spelling you meet depends on who wrote the chart.
How to play Ab7sus4
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.
Ab7sus4 has 13 of them, on the top four strings, the bottom four strings and the middle four strings, from open position up to the 13th — every inversion the chord has: Ab in the bass, Db in the bass, Eb in the bass and Gb in the bass. The one to learn first is the Eb 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 xxx122 — no barre and only 3 fretted notes. None of the shapes for Ab7sus4 uses an open string, so every one of them is movable; the lowest sits at the 1st fret. 3 of the 7 need a barre. Together they cover the neck from the 1st fret to the 14th.
| Frets | Where | Bass | Top | Hand |
|---|---|---|---|---|
| xxx122 | 1st fret | Ab, root position | Gb | all fretted |
| xx1122 | 1st fret | Eb, 2nd inversion | Gb | all fretted |
| 464644 | 4th fret | Ab, root position | Ab | barred |
| xx6879 | 6th fret | Ab, root position | Db | all fretted |
| x-11-11-11-9-9 | 9th fret | Ab, root position | Db | barred |
| x-11-13-11-14-11 | 11th fret | Ab, root position | Eb | barred |
| x-x-13-13-14-14 | 13th fret | Eb, 2nd inversion | Gb | all fretted |
The same notes rebuilt from scratch give 5 shell and 9 drop 3 voicings, each on its own page.
Tensions. A shell of Ab7sus4, 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 Ab7sus4
In which keys. Every note of Ab7sus4 belongs to C# major (the V), C# minor (the v), Eb minor (the iv), E major (the iii), F# major (the ii), Ab minor (the i), Bb minor (the ♭VII) and B major (the vi).
What to play over Ab7sus4
Every note of Ab7sus4 is in Ab minor pentatonic, Ab blues, Ab mixolydian, Ab dorian and Ab natural minor.
Chords near Ab7sus4
Change one note of Ab7sus4 and you have Absus4 (drop the flat seventh), Abm7 (the fourth becomes a minor third), Ab7 (the fourth becomes a major third) or Ab11 (add the ninth).
Ab7sus4 is a suspended chord — root and fifth, with a second or fourth where the third would be — or nothing at all. Suspended and power chords on every root.
On Ab7sus4’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.