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B♭ diminished chord on bass (B♭dim)
Also called or written B♭dim or B♭°
B♭ diminished contains B♭, D♭, and F♭. This four-string shape spans frets 6–8 and suits intermediate players.
How it is built
Formula 1, ♭3, ♭5
How do you play a B♭ diminished chord on bass?
B♭ diminished is played at the 6th fret as 6 7 8 6: index finger on the E string at fret 6, ring finger on the A string at fret 7, pinky finger on the D string at fret 8 and middle finger on the G string at fret 6.
Full note and interval breakdown
| String | Fret | Finger | Note |
|---|---|---|---|
| 4 (E) | 6 | 1 | B♭ (1) |
| 3 (A) | 7 | 3 | F♭ (♭5) |
| 2 (D) | 8 | 4 | B♭ (1) |
| 1 (G) | 6 | 2 | D♭ (♭3) |
IntermediateThe pinky must reach the 8th fret on the D string while the middle finger holds the G string at the 6th fret.
B♭dim/D♭ inversion
B♭ diminished is played at the 7th fret as 9 7 8 9: ring finger on the E string at fret 9, index finger on the A string at fret 7, middle finger on the D string at fret 8 and pinky finger on the G string at fret 9.
Full note and interval breakdown
| String | Fret | Finger | Note |
|---|---|---|---|
| 4 (E) | 9 | 3 | D♭ (♭3) |
| 3 (A) | 7 | 1 | F♭ (♭5) |
| 2 (D) | 8 | 2 | B♭ (1) |
| 1 (G) | 9 | 4 | F♭ (♭5) |
B♭dim/F♭ inversion · fret 6
B♭ diminished is played at the 6th fret as × 7 8 6: middle finger on the A string at fret 7, ring finger on the D string at fret 8 and index finger on the G string at fret 6. The E string stays muted.
Full note and interval breakdown
| String | Fret | Finger | Note |
|---|---|---|---|
| 4 (E) | muted | — | — |
| 3 (A) | 7 | 2 | F♭ (♭5) |
| 2 (D) | 8 | 3 | B♭ (1) |
| 1 (G) | 6 | 1 | D♭ (♭3) |
B♭dim/F♭ inversion · fret 11
B♭ diminished is played at the 11th fret as 12 13 11 ×: middle finger on the E string at fret 12, ring finger on the A string at fret 13 and index finger on the D string at fret 11. The G string stays muted.
Full note and interval breakdown
| String | Fret | Finger | Note |
|---|---|---|---|
| 4 (E) | 12 | 2 | F♭ (♭5) |
| 3 (A) | 13 | 3 | B♭ (1) |
| 2 (D) | 11 | 1 | D♭ (♭3) |
| 1 (G) | muted | — | — |
Why it sounds like that
B♭ diminished is built from the 1, ♭3, ♭5 formula. The diminished 5th between B♭ and F♭ creates its tense, unstable quality. Compare it to B♭ minor, which raises the fifth to F.
What goes wrong with B♭ diminished?
- Letting the pinky collapse and buzz on the D string.
- Allowing the middle finger to touch the A string and mute the D♭.
When to use it
B♭ diminished works over B♭ minor and B♭ 5th chords. It also fits C♯ major and C♯ minor progressions. Use it for tense passing lines in jazz or metal.
Changing to and from B♭ diminished
- Sliding the shape down two frets to the 4th fret gives A♭ diminished.
- Sliding the shape up one fret to the 7th fret gives B diminished.
Which voicing to use
The 6th fret position puts B♭ in the bass for a root-position sound. The B♭dim/C♯ inversion starts on D♭ at the 7th fret, giving a darker, less stable feel.
Other B♭ chords
Common questions
How is B♭ diminished written?
B♭ diminished is written B♭° or B♭dim. The root is typed as Bb in ASCII. It is also spelled A♯ in enharmonic notation for the same sounding root.
What is the difference between B♭ diminished and B♭ minor?
B♭ diminished has a diminished 5th (F♭), while B♭ minor has a perfect 5th (F). The lowered fifth gives the diminished chord its tense sound.
Can B♭ diminished be played in a lower register?
Yes, the B♭dim/E inversion at the 6th fret on the G string uses only three strings, starting on F♭. It omits the low E string for a lighter texture.