Construction
A 9♯11 = Root + Major 3rd + Perfect 5th + Minor 7th + Major 2nd + Diminished 5th = A, C♯, E, G, B, D♯
| Note | Interval | Degree |
|---|---|---|
| A | Root | 1 |
| C♯ | Major 3rd | 3 |
| E | Perfect 5th | 5 |
| G | Minor 7th | ♭7 |
| B | Major 2nd | 9 |
| D♯ | Diminished 5th | ♭5 |
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 A Major:
A 9♯11 : Frequently Asked Questions
What is the A 9♯11 chord on piano?
The A 9♯11 chord contains the notes A – C♯ – E – G – B – D♯. On piano, play these notes together to sound the chord.