The A 9♯11 chord is a six-note chord made up of A, B, C♯, D♯, E, and G.
Construction
A 9♯11 = Root + Major 2nd + Major 3rd + Diminished 5th + Perfect 5th + Minor 7th = A · B · C♯ · D♯ · E · G
| Note | Interval | Degree |
|---|---|---|
| A | Root | 1 |
| B | Major 2nd | 9 |
| C♯ | Major 3rd | 3 |
| D♯ | Diminished 5th | ♭5 |
| E | Perfect 5th | 5 |
| G | Minor 7th | ♭7 |
Key Signature
A chord has no key signature of its own, but the A 9♯11 is the tonic (I) chord of A Major, whose key signature has 3 sharps (F♯, C♯, G♯).
F♯C♯G♯
Order of sharps
Sharps are added to a key signature in a fixed order. Each new sharp key adds the next sharp on the list.
F♯C♯G♯D♯A♯E♯B♯
Mnemonic: Father Charles Goes Down And Ends Battle
Chords in the Key of A Major
These are the triads built on each degree of the A major scale:
A 9♯11 — Frequently Asked Questions
What is the A 9♯11 chord on piano?
The A 9♯11 chord contains the notes A – B – C♯ – D♯ – E – G. On piano, play these notes together to sound the chord.