The A♯ 7♯9 chord is a five-note chord made up of A♯, C♯♯, E♯, G♯, and B♯♯. It is built from a root, major third, perfect fifth, minor seventh, and augmented ninth.
Construction
A♯ 7♯9 = Root + Major 3rd + Perfect 5th + Minor 7th + Minor 3rd = A♯ · C♯♯ · E♯ · G♯ · B♯♯
| Note | Interval | Degree |
|---|---|---|
| A♯ | Root | 1 |
| C♯♯ | Major 3rd | 3 |
| E♯ | Perfect 5th | 5 |
| G♯ | Minor 7th | ♭7 |
| B♯♯ | Minor 3rd | ♭3 |
Key Signature
A chord has no key signature of its own, but the A♯ 7♯9 is the tonic (I) chord of A# Major, whose key signature has 2 flats (B♭, E♭).
B♭E♭
Order of flats
Flats are added in a fixed order — the reverse of the sharp order. Each new flat key adds the next flat on the list.
B♭E♭A♭D♭G♭C♭F♭
Mnemonic: Battle Ends And Down Goes Charles’ Father
Chords in the Key of A♯ Major
These are the triads built on each degree of the A♯ major scale:
A♯ 7♯9 — Frequently Asked Questions
What is the A♯ 7♯9 chord on piano?
The A♯ 7♯9 chord contains the notes A♯ – C♯♯ – E♯ – G♯ – B♯♯. On piano, play these notes together to sound the chord.
What notes are in the A# 7♯9 chord?
The A# 7♯9 chord (A#7♯9) contains 5 notes: A#, D, F, G#, C#. Formula: R-M3-P5-m7-A9.
How is A#7♯9 used in music?
A#7♯9 is used in jazz, fusion, and contemporary music to add harmonic color. It appears as a dominant or tonic chord depending on context.
What is the scale degree formula for A#7♯9?
A#7♯9 uses scale degrees 1-3-5-b7-#9, giving it its distinctive sound.