A

Aadd9

Notes

A · C# · E · B

Intervals

  • RootA (1P)
  • Major 3rdC# (3M)
  • Perfect 5thE (5P)
  • Major 9thB (9M)

Fretboard

EBGDAE357912EABC#EBC#EABABC#EEABC#ABC#EAEABC#E

About

The Aadd9 (A–C♯–E–B) adds a ninth to a major triad without including a 7th. The distinction matters: because there is no 7th, the chord stays harmonically stable and resolved rather than suggesting dominant or subdominant motion. The B adds brightness and shimmer; the C♯ retains the major identity. On guitar, open-string voicings make add9 sounds particularly resonant. The 5th can be omitted without loss; the 3rd and 9th are both essential. Compared to AMaj9, add9 is simpler and more grounded — a major triad with a single added color. Compared to plain A, the 9th adds a touch of modern shimmer.

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