The A♯ 9sus4 chord is a five-note chord made up of A♯, D♯, E♯, G♯, and B♯. It is built from a root, perfect fourth, perfect fifth, minor seventh, and major ninth.
Construction
A♯ 9sus4 = Root + Perfect 4th + Perfect 5th + Minor 7th + Major 2nd = A♯ · D♯ · E♯ · G♯ · B♯
| Note | Interval | Degree |
|---|---|---|
| A♯ | Root | 1 |
| D♯ | Perfect 4th | 11 |
| E♯ | Perfect 5th | 5 |
| G♯ | Minor 7th | ♭7 |
| B♯ | Major 2nd | 9 |
Key Signature
A chord has no key signature of its own, but the A♯ 9sus4 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:
Same Notes, Other Names
The notes A♯ – D♯ – E♯ – G♯ – B♯ aren’t exclusive to this chord. Depending on which note is the bass and how the chord functions, the same pitches also spell:
A♯ 9sus4 — Frequently Asked Questions
What is the A♯ 9sus4 chord on piano?
The A♯ 9sus4 chord contains the notes A♯ – D♯ – E♯ – G♯ – B♯. On piano, play these notes together to sound the chord.
What notes are in the A# 9sus4 chord?
The A# 9sus4 chord (A#9sus4) contains 5 notes: A#, D#, F, G#, C. Formula: R-P4-P5-m7-M9.
How is A#9sus4 used in music?
A#9sus4 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#9sus4?
A#9sus4 uses scale degrees 1-4-5-b7-9, giving it its distinctive sound.