B7b9 B dominant seventh flat nine chord
- Notes
- B D# F# A C
- Formula
- 1 3 5 b7 b9
- Semitones
- 0 4 7 10 13 above the root
- Other symbols
- B7(b9), B7-9
B to D# is a major third (4 semitones), D# to F# is a minor third (3 semitones), F# to A is a minor third (3 semitones), A to C is a minor third (3 semitones). A dominant seventh with a flattened ninth, C, 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.
B7b9 on the piano
Root position from B4: B4, D#5, F#5, A5, C6. Middle C is C4.
B7b9 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 B as its lowest note.
x 2 1 2 1 x (low E to high e)
Sounds B2 D#3 A3 C4, fifth left out
7 x 7 8 7 8 (low E to high e)
Sounds B2 A3 D#4 F#4 C5
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 B7b9
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 | B D# F# A C | B7b9 | |
| 1st inversion | D# F# A C B | B7b9/D# | |
| 2nd inversion | F# A C B D# | B7b9/F# | |
| 3rd inversion | A C B D# F# | B7b9/A | |
| 4th inversion | C B D# F# A | B7/C (also read as B7b9/C) |
Where B7b9 fits
B7b9 is V7b9 in E minor. Its upper four notes D# F# A C are D#dim7, so B7b9 and that diminished seventh are interchangeable over a B bass. The flat ninth C falls a half step to the fifth of Em.