Ab7#9 Ab dominant seventh sharp nine chord
- Notes
- Ab C Eb Gb B
- Formula
- 1 3 5 b7 #9
- Semitones
- 0 4 7 10 15 above the root
- Also written
- G#7#9 (G# B# D# F# A##)
- Other symbols
- Ab7(#9), Ab7+9
Ab to C is a major third (4 semitones), C to Eb is a minor third (3 semitones), Eb to Gb is a minor third (3 semitones), Gb to B is a perfect fourth (5 semitones). A dominant seventh with a raised ninth, B. On the keyboard B is the same key as the minor third, so the chord holds both a major and a minor third; it is written as a sharp ninth because it sits above the seventh and the letter names follow the stack of thirds.
Ab7#9 on the piano
Root position from Ab4: Ab4, C5, Eb5, Gb5, B5. Middle C is C4.
Ab7#9 on the guitar
Standard tuning (E A D G B E). Strings run low E on the left to high e on the right, frets downwards; × is a muted string, ○ an open string, and each dot shows the note it sounds, with the root in blue-green. Every shape below has Ab as its lowest note.
x 11 10 11 12 x (low E to high e)
Sounds Ab3 C4 Gb4 B4, fifth left out
The E-shape and A-shape grips are movable: an E-shape chord's root is the note under your first finger on the low E string, an A-shape chord's root is the note on the A string. Slide the same grip up or down to play dominant seventh sharp nine chords on other roots.
Inversions of Ab7#9
An inversion puts a note other than the root in the bass. The name is what semicord's chord finder calls those notes played bottom to top; a slash name like C/E means a C chord with E in the bass.
| Position | Notes, bass first | Named | Listen |
|---|---|---|---|
| Root position | Ab C Eb Gb B | Ab7#9 | |
| 1st inversion | C Eb Gb B Ab | G#m7/C (also written Abm7/C; also read as Ab7#9/C) | |
| 2nd inversion | Eb Gb B Ab C | Ab7#9/Eb | |
| 3rd inversion | Gb B Ab C Eb | Ab7#9/Gb | |
| 4th inversion | B Ab C Eb Gb | Ab7/B (also read as Ab7#9/B) |
Where Ab7#9 fits
Ab7#9 has no place among the chords built from a major or minor scale: it holds a major third, C, and the sharp ninth B, which sounds the same as the minor third. That major–minor clash is the blues in one chord. It is used as the I chord of a blues or a funk vamp, and as a tense V chord in jazz; Jimi Hendrix's "Purple Haze" made E7#9 famous, which is why guitarists call it the Hendrix chord.