A9 chord
A dominant ninth. One shape on the neck below, with the notes it's built from and the keys it belongs to.
Notes
- A
- 1
- C#
- 3
- E
- 5
- G
- b7
- B
- 9
The major third is what makes it sound bright and settled.
The minor seventh adds a bluesy edge and leaves the chord sounding unfinished.
The 9th adds color on top without changing whether it's major or minor.
How to play A9
- Root on A
- x-12-11-12-12-12
Want to know why this chord works where it does? The Intermediate lessons cover it, and founding players get them first.
Keys with A9
A9 uses only notes from D major and B minor. It sounds most at home in D major.