C7b9 C dominant seventh flat nine chord
- Notes
- C E G Bb Db
- Formula
- 1 3 5 b7 b9
- Semitones
- 0 4 7 10 13 above the root
- Other symbols
- C7(b9), C7-9
C to E is a major third (4 semitones), E to G is a minor third (3 semitones), G to Bb is a minor third (3 semitones), Bb to Db is a minor third (3 semitones). A dominant seventh with a flattened ninth, Db, a half step (plus an octave) above the root. It is the sharpest-sounding of the common dominant chords and pulls hard towards a minor tonic.
C7b9 on the piano
Root position from C4: C4, E4, G4, Bb4, Db5. Middle C is C4.
C7b9 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 C as its lowest note.
x 3 2 3 2 x (low E to high e)
Sounds C3 E3 Bb3 Db4, fifth left out
8 x 8 9 8 9 (low E to high e)
Sounds C3 Bb3 E4 G4 Db5
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 dominant seventh flat nine chords on other roots.
Inversions of C7b9
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 | C E G Bb Db | C7b9 | |
| 1st inversion | E G Bb Db C | C7b9/E | |
| 2nd inversion | G Bb Db C E | C7b9/G | |
| 3rd inversion | Bb Db C E G | C7b9/Bb | |
| 4th inversion | Db C E G Bb | C7/Db (also read as C7b9/Db) |
Where C7b9 fits
C7b9 is V7b9 in F minor. Its upper four notes E G Bb Db are Edim7, so C7b9 and that diminished seventh are interchangeable over a C bass. The flat ninth Db falls a half step to the fifth of Fm.