Bb9 Bb dominant ninth chord
- Notes
- Bb D F Ab C
- Formula
- 1 3 5 b7 9
- Semitones
- 0 4 7 10 14 above the root
- Also written
- A#9 (A# C## E# G# B#)
- Other symbols
- Bbdom9
Bb to D is a major third (4 semitones), D to F is a minor third (3 semitones), F to Ab is a minor third (3 semitones), Ab to C is a major third (4 semitones). A dominant seventh (Bb7) with the ninth, C, on top. Guitarists usually leave out the fifth, F; the chord still reads as Bb9 while the third D and seventh Ab are there.
Bb9 on the piano
Root position from Bb4: Bb4, D5, F5, Ab5, C6. Middle C is C4.
Bb9 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 Bb as its lowest note.
x 1 0 1 1 1 (low E to high e)
Sounds Bb2 D3 Ab3 C4 F4
6 8 6 7 6 8 (low E to high e)
Sounds Bb2 F3 Ab3 D4 F4 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 ninth chords on other roots.
Inversions of Bb9
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 | Bb D F Ab C | Bb9 | |
| 1st inversion | D F Ab C Bb | Bb9/D | |
| 2nd inversion | F Ab C Bb D | Bb9/F | |
| 3rd inversion | Ab C Bb D F | Bb9/Ab | |
| 4th inversion | C Bb D F Ab | Bb7/C (also read as Bb9/C) |
Where Bb9 fits
Bb9 is V9 in Eb major. It resolves like Bb7. In funk and blues it is also played as I9, IV9 and V9 of a twelve-bar blues, with no pull to resolve at all. Without the root, its upper four notes D F Ab C are Dm7b5, which is why pianists who leave the root to the bass player grab that shape.