Aadd9 A major add nine chord
- Notes
- A C# E B
- Formula
- 1 3 5 9
- Semitones
- 0 4 7 14 above the root
- Other symbols
- A(add9), Aadd2
A to C# is a major third (4 semitones), C# to E is a minor third (3 semitones), E to B is a perfect fifth (7 semitones). A major triad with the ninth, B, added and no seventh. The ninth is the second of the scale an octave up, so with B played right next to the root the same chord is often written Aadd2. It is not Asus2: the third C# is still there.
Aadd9 on the piano
Root position from A4: A4, C#5, E5, B5. Middle C is C4.
Aadd9 on the guitar
Standard tuning (E A D G B E). Strings run low E on the left to high e on the right, frets downwards; × is a muted string, ○ an open string, and each dot shows the note it sounds, with the root in blue-green. Every shape below has A as its lowest note.
5 4 x 4 5 x (low E to high e)
Sounds A2 C#3 B3 E4
x 12 11 x 12 12 (low E to high e)
Sounds A3 C#4 B4 E5
The E-shape and A-shape grips are movable: an E-shape chord's root is the note under your first finger on the low E string, an A-shape chord's root is the note on the A string. Slide the same grip up or down to play major add nine chords on other roots.
Inversions of Aadd9
An inversion puts a note other than the root in the bass. The name is what semicord's chord finder calls those notes played bottom to top; a slash name like C/E means a C chord with E in the bass.
| Position | Notes, bass first | Named | Listen |
|---|---|---|---|
| Root position | A C# E B | Aadd9 | |
| 1st inversion | C# E B A | Aadd9/C# | |
| 2nd inversion | E B A C# | Aadd9/E | |
| 3rd inversion | B A C# E | A/B (also read as Aadd9/B) |
Where Aadd9 fits
Aadd9 is I in A major, IV in E major, V in D major. The added B belongs to all three of those keys, so Aadd9 can stand in for A wherever it appears; it keeps the major sound but softens it. It is not a substitute for A9, which also has the seventh G.