My Guitar Notes

Ab7#9 — Ab dominant seventh sharp nine chord

A dominant seventh chord with a raised ninth. It contains both the major third and the minor third in the octave above, which is what produces the chord's bite.

Symbol
Ab7#9
Root
Ab
Quality
Dominant seventh sharp nine
Family
altered
Notes
Ab C Eb Gb B
Degree formula
1 3 5 b7 #9
Semitones from the root
0 3 4 7 10
Distinct pitch classes
5
Interval structure
Stacked from the root: 4 semitones, 3 semitones, 3 semitones, 5 semitones
Notation
Written 7#9, and long associated in popular usage with the chord in the introduction to Purple Haze, hence its common nickname.
Key
Ab · Ab major / F minor key signature

Formula

The chord tones in order from the root, with the interval each one forms above it.

DegreeNoteSemitonesInterval from the root
1Ab0Perfect unison
3C4Major third
5Eb7Perfect fifth
b7Gb10Minor seventh
#9B3Minor third

Inversions

An inversion is the same set of notes with a different one in the bass. The last column gives the distance of each note above the bass note, in semitones.

InversionBass noteDegree in the bassNotes above the bassSemitones above the bass
root positionAb1Ab – C – Eb – Gb – B0 4 7 10 3
first inversionC3C – Eb – Gb – B – Ab0 3 6 11 8
second inversionEb5Eb – Gb – B – Ab – C0 3 8 5 9
third inversionGbb7Gb – B – Ab – C – Eb0 5 2 6 9
fourth inversionB#9B – Ab – C – Eb – Gb0 9 1 4 7

Playable voicings

These shapes were found by searching the fretboard of a standard-tuned guitar (E A D G B E) rather than copied from a chord book. The search allows every string to sound or to be muted, rejects any shape with a muted string between two sounding strings, rejects any shape whose fretted notes span more than four frets (a five-fret window), requires every chord tone to be present, and then sorts what remains with root-position shapes first and the most compact, lowest shapes next. The shapes shown are the first six of that ordering; other orderings are possible at the same frets.

#Shape (low string first)NotesDegreesBassSpan (frets)Sounding strings
14-3-4-4-4-4Ab C Gb B Eb Ab1 3 b7 #9 5 1Ab16
24-3-4-4-4-2Ab C Gb B Eb Gb1 3 b7 #9 5 b7Ab26
34-2-1-1-1-2Ab B Eb Ab C Gb1 #9 5 1 3 b7Ab36
44-2-1-4-1-2Ab B Eb B C Gb1 #9 5 #9 3 b7Ab36
54-3-1-4-1-2Ab C Eb B C Gb1 3 5 #9 3 b7Ab36
64-3-1-4-4-2Ab C Eb B Eb Gb1 3 5 #9 5 b7Ab36

Shape numbers run from the lowest string to the highest, so the left-hand number is the sixth string (low E) in standard tuning. Multiple shapes are listed because a chord can be voiced several ways, and because a lower position is not always the better sounding one.

Related chords and scales

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