The A 9♯5 chord is a five-note chord made up of A, C♯, E♯, G, and B. It is built from a root, major third, augmented fifth, minor seventh, and major ninth.
Construction
A 9♯5 = Root + Major 3rd + Minor 6th + Minor 7th + Major 2nd = A · C♯ · E♯ · G · B
| Note | Interval | Degree |
|---|---|---|
| A | Root | 1 |
| C♯ | Major 3rd | 3 |
| E♯ | Minor 6th | ♯5 |
| G | Minor 7th | ♭7 |
| B | Major 2nd | 9 |
Key Signature
A chord has no key signature of its own, but the A 9♯5 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:
Same Notes, Other Names
The notes A – C♯ – 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 9♯5 — Frequently Asked Questions
What is the A 9♯5 chord on piano?
The A 9♯5 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 9♯5 chord?
The A 9♯5 chord (A9♯5) contains 5 notes: A, C#, F, G, B. Formula: R-M3-A5-m7-M9.
How is A9♯5 used in music?
A9♯5 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 A9♯5?
A9♯5 uses scale degrees 1-3-#5-b7-9, giving it its distinctive sound.