Package leaflet · Information for the musician · Chord
A Seventh Sharp Nine Chord (A7♯9)
Gritty, funky and aggressive. The sharp ninth rubs against the major third, combining major and minor colours in one chord.
- A7♯9
- 5 notes
- 532223
1Composition: what it contains
A – C♯ – E – G – B♯
- Symbol
- A7♯9
- Also written
- A7♯9, A7(♯9), A7+9
- Formula
- 1 3 5 ♭7 ♯9
| Degree | Note | Interval | Semitones |
|---|---|---|---|
| 1 | A | unison | 0 |
| 3 | C♯ | major third | 4 |
| 5 | E | perfect fifth | 7 |
| ♭7 | G | minor seventh | 10 |
| ♯9 | B♯ | augmented ninth | 15 |
2Appearance: diagrams and sound
On the guitar
532223fret 2
575658fret 5
x-12-11-12-13-xfret 11On the ukulele
2034open position
5754fret 4
12-12-9-12fret 9On the piano
On the staff
On bass and as an arpeggio
3Indications: what it is used for
Famous in rock, funk, blues-rock and soul as a tonic dominant chord with attitude, and in jazz as an altered V7 resolving to I or i. Its sharp ninth is enharmonic to the minor third, so it suits minor-pentatonic soloing over a dominant groove. In jazz, the altered scale or half-whole diminished scale fits over it. It frequently appears in blues and funk vamps and as the V chord in minor ii–V–i progressions.
4Dosage: how to practise it
On guitar, learn the classic shape rooted on the fifth string (root, 3, ♭7, ♯9) and practise funk rhythms at 90–120 BPM, muting between hits. On piano, play the left-hand voicing 3-♭7-♯9 and the right-hand altered voicings. Practise iiø7–V7♯9–im and a twelve-bar blues with every chord as 7♯9. Arpeggiate the chord. Five to ten minutes daily. On piano, practise comping with short, accented hits. Try improvising with the blues scale over a 7♯9 vamp, then with the altered scale, to hear both colours.
5Warnings and common mistakes
The sharp ninth is not a minor third: it sits above the major third, which must also be present. Do not confuse 7♯9 with m7, which has no major third. Avoid placing the ♯9 below the third in voicings, which turns the sound into a muddy minor chord. In a major ii–V–I, the sharp ninth may clash with a melody containing the natural ninth. The symbol '7+9' is ambiguous; prefer 7♯9.
6Interactions with chords, scales and keys
Inversions
- Inversion 1 · A7♯9/C♯ · C♯ – E – G – B♯ – A
- Inversion 2 · A7♯9/E · E – G – B♯ – A – C♯
- Inversion 3 · A7♯9/G · G – B♯ – A – C♯ – E
- Inversion 4 · A7♯9/B♯ · B♯ – A – C♯ – E – G
Scales to play over A7♯9
7Other presentations available
The same chord from every note
C7♯9 C♯7♯9 D7♯9 E♭7♯9 E7♯9 F7♯9 F♯7♯9 G7♯9 A♭7♯9 B♭7♯9 B7♯9
Other chords on A
A Am Adim Aaug Asus2 Asus4 A5 A6 Am6 A7 Amaj7 Am7 Am7♭5 Adim7 Am(maj7) A7sus4 Aadd9 Am(add9) A6/9 A9 Amaj9 Am9 A11 Am11 A13 A7♭9 A7♯5 A7♭5
Read this leaflet carefully before playing. Keep it near your instrument. Free to use, print and share for personal and educational use.