A# dominant 7th sharp 9 · Piano
A#7♯9 Chord on Piano
The A#7♯9 chord (A# dominant 7th sharp 9) is built from the notes A#, D, F, G# and C#. The keyboard diagram below shows exactly which keys to press. The same chord is also written Bb7♯9; both spellings sound identical.
Chord diagrams
Notes in this chord
- A♯
- D
- F
- G♯
- C♯
Degrees: 1 – 3 – 5 – ♭7 – ♯9
Also written: Bb7♯9
How to play
To play A#7♯9 on piano, press A#, D, F, G# and C# together. In root position the lowest note is A#, and the finger numbers follow the keys left to right in the diagram.
Theory behind the chord
Often called the Hendrix chord, the 7♯9 stacks a sharpened ninth over a dominant seventh. Major and minor thirds sound at once, producing the gritty clash that defines psychedelic rock and funk. On A#7♯9 this structure sits on the root A#, so the degrees 1 – 3 – 5 – ♭7 – ♯9 map onto A#, D, F, G# and C#.
Frequently asked questions
- Which notes are in the A#7♯9 chord?
- A#7♯9 contains the notes A#, D, F, G# and C#. Relative to the root these are the degrees 1 – 3 – 5 – ♭7 – ♯9.
- Are A#7♯9 and Bb7♯9 the same chord?
- Yes. A#7♯9 and Bb7♯9 are enharmonically identical — the spelling differs but the frets and keys are the same. Which name is used depends on the key of the piece.
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