A7#9 — A 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.
- 1 = A
- 3 = C#
- 5 = E
- b7 = G
- #9 = B#
- Symbol
- A7#9
- Root
- A
- Quality
- Dominant seventh sharp nine
- Family
- altered
- Notes
- A C# E G 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
- A · A major / F# minor key signature
Formula
The chord tones in order from the root, with the interval each one forms above it.
| Degree | Note | Semitones | Interval from the root |
|---|---|---|---|
| 1 | A | 0 | Perfect unison |
| 3 | C# | 4 | Major third |
| 5 | E | 7 | Perfect fifth |
| b7 | G | 10 | Minor seventh |
| #9 | B# | 3 | Minor 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.
| Inversion | Bass note | Degree in the bass | Notes above the bass | Semitones above the bass |
|---|---|---|---|---|
| root position | A | 1 | A – C# – E – G – B# | 0 4 7 10 3 |
| first inversion | C# | 3 | C# – E – G – B# – A | 0 3 6 11 8 |
| second inversion | E | 5 | E – G – B# – A – C# | 0 3 8 5 9 |
| third inversion | G | b7 | G – B# – A – C# – E | 0 5 2 6 9 |
| fourth inversion | B# | #9 | B# – A – C# – E – G | 0 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) | Notes | Degrees | Bass | Span (frets) | Sounding strings |
|---|---|---|---|---|---|---|
| 1 | 5-4-5-5-5-5 | A C# G C E A | 1 3 b7 #9 5 1 | A | 1 | 6 |
| 2 | 5-4-5-5-5-3 | A C# G C E G | 1 3 b7 #9 5 b7 | A | 2 | 6 |
| 3 | 5-3-2-2-2-3 | A C E A C# G | 1 #9 5 1 3 b7 | A | 3 | 6 |
| 4 | 5-3-2-5-2-3 | A C E C C# G | 1 #9 5 #9 3 b7 | A | 3 | 6 |
| 5 | 5-4-2-5-2-3 | A C# E C C# G | 1 3 5 #9 3 b7 | A | 3 | 6 |
| 6 | 5-4-2-5-5-3 | A C# E C E G | 1 3 5 #9 5 b7 | A | 3 | 6 |
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
- KeyEverything in A
- ScaleA diminished (half-whole)
- ChordA7
- ChordA7b5
Related
- KeyKey of A
- ScaleA diminished (half-whole)
- ChordA7 — Dominant seventh
- ChordA7b5 — Dominant seventh flat five
- ChordA11 — Dominant eleventh
- ChordA13 — Dominant thirteenth
- ChordA6 — Sixth
- DegreesA — degree map