A9
A Dominant 9th
1 3 5 ♭7 9
Notes in A9
AR
C♯3
E5
G♭7
B9
The A9 chord contains 5 notes: A, C♯, E, G, B
Intervals
| Interval | Semitones | Note | Function |
|---|---|---|---|
| R | 0 | A | Root |
| 3 | 4 | C♯ | Major 3rd |
| 5 | 7 | E | Perfect 5th |
| ♭7 | 10 | G | Minor 7th |
| 9 | 2 | B | Major 9th |
About A Dominant 9th Chords
Dominant 9th chords extend the dominant 7th with a 9th, adding richness to blues and funk progressions. James Brown's rhythm guitar was built on 9th chord stabs. They have more color than a plain 7th but stay firmly in dominant territory.
Compatible Scales & Modes
These scales contain all the notes of A9 and can be used for soloing, improvising, and writing melodies over this chord.
A Mixolydian
Contains all the chord tones. The standard scale for dominant 9th chords.
A Blues Scale
Adds grit and attitude over dominant 9th voicings — essential for blues and funk.