Ab7 guitar chord
An open string left ringing against a fretted grip. Because it costs no finger, it sounds a note the closed shape has none left for -- a tension on top, or a pedal root underneath. Either a familiar grip with open strings added, or a shape so sparse the open strings carry the chord. These belong to their key rather than to a shape, so D, A, G and E have many and Eb a handful.
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- Fingers, notes or intervals
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About Ab7 — open string voicings
Ab7 is Ab, C, Eb and Gb — Ab with the flat seventh added on top.
It sounds restless and pointed at something. The third and the flat seventh are a tritone apart and each moves by a semitone into the next chord; that is the engine of a cadence, and the whole vocabulary of the blues.
Ab7 notes and formula
| Ab | C | Eb | Gb |
|---|---|---|---|
| 1 | 3 | 5 | ♭7 |
Dominant — it points a fifth down.
Also written Abdom7 or Ab dominant 7. The same chord either way; which spelling you meet depends on who wrote the chart.
How to play Ab7
An open string left ringing against a fretted grip. It costs no finger, so it can sound a note the closed shape has none left for: a tension on top, or a pedal root underneath.
These belong to their key rather than to a shape: they cannot be moved up the neck. D, A, G and E have many; E♭ has a handful.
Ab7 has 5 of them, on strings 6-4-3-2-1, strings 6-5-4-3-2, the bottom four strings and strings 6-4-3-2, from the 2nd fret up to the 4th — every inversion the chord has: Ab in the bass and Gb in the bass. The one to learn first is the Ab shape at the 4th fret, which is the easiest grip here.
Start with xx6878 — no barre. None of the shapes for Ab7 uses an open string, so every one of them is movable; the lowest sits at the 1st fret. 4 of the 6 need a barre. Together they cover the neck from the 1st fret to the 13th.
| Frets | Where | Bass | Top | Hand |
|---|---|---|---|---|
| xx1112 | 1st fret | Eb, 2nd inversion | Gb | barred |
| 431112 | 1st fret | Ab, root position | Gb | barred |
| 464544 | 4th fret | Ab, root position | Ab | barred |
| xx6878 | 6th fret | Ab, root position | C | all fretted |
| x-11-10-11-9-x | 9th fret | Ab, root position | Ab | all fretted |
| x-11-13-11-13-11 | 11th fret | Ab, root position | Eb | barred |
The same notes rebuilt from scratch give 4 shell, 14 drop 2 and 9 drop 3 voicings, each on its own page.
Tensions. A shell of Ab7, root, third and seventh, leaves a string free, and the tones that belong over it are the b9 (Bbb), the 9 (Bb), the #9 (B), the #11 (D), the b13 (Fb) and the 13 (F).
How to use Ab7
Ab7 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 Ab7 belongs to C# major (the V, the dominant) and Bb minor (the ♭VII).
What to play over Ab7
Every note of Ab7 is in Ab mixolydian, Ab lydian dominant and Ab half-whole diminished.
Chords near Ab7
Change one note of Ab7 and you have Ab (drop the flat seventh), Abmaj7 (the flat seventh becomes a major seventh), Abm7 (the major third becomes a minor third), Abadd9 (the flat seventh becomes a ninth), Ab6 (the flat seventh becomes a sixth) or Ab7sus4 (the major third becomes a fourth).
Ab7 is a dominant chord — root, major third, fifth, minor seventh. Dominant seventh chords on every root.
On Ab7’s sound and use this page follows Edward Aldwell & Carl Schachter, Harmony and Voice Leading (Schirmer / Cengage, 4th ed., 2011). The shapes and the derived voicings come from different places, and both are explained in where the chords and the theory come from.