C9 chord: dominant ninth
C9 is the dominant ninth chord on C: C, E, G, Bb and D (1–3–5–b7–9). C9 stacks the root C, the major third E, the perfect fifth G, the minor seventh Bb and the major ninth D. The 9 is the dominant chord with the ninth.
Notes in C9: C – E – G – Bb – DFormula: 1 – 3 – 5 – b7 – 9In the formula, the numbers count steps of the major scale starting from the note that names the chord; "b" lowers a half step, "#" raises one — and a slash names the bass note.
It keeps the dominant function and adds color and breadth.
The same chord on all four instruments
Where to use it
Blues, funk, choro and broader dominants.
Part of the Extended family.