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B 7th flat 5 chord on ukulele (B7♭5)
Also called or written B7♭5, B, B Dominant 7th Flat 5 or B 7th ♭5
B 7th flat 5 is built from B, D♯, F, and A. The 4th fret shape stacks three fingers in a row before the pinky reaches fret 6.
How it is built
Formula 1, 3, ♭5, ♭7
- Root positionB–D♯–F–AB7♭510-11-11-12
- First inversionD♯–F–A–BB7♭5/D♯2-3-1-2
- Second inversionF–A–B–D♯B7♭5/F4-5-5-6
- Third inversionA–B–D♯–FB7♭5/A8-9-7-8
How do you play a B 7th flat 5 chord on ukulele?
B 7th flat 5 is played at the 4th fret as 4 5 5 6: index finger on the G string at fret 4, middle finger on the C string at fret 5, ring finger on the E string at fret 5 and pinky finger on the A string at fret 6.
Full note and interval breakdown
| String | Fret | Finger | Note |
|---|---|---|---|
| 4 (G) | 4 | 1 | B (1) |
| 3 (C) | 5 | 2 | F (♭5) |
| 2 (E) | 5 | 3 | A (♭7) |
| 1 (A) | 6 | 4 | D♯ (3) |
AdvancedThe pinky must reach fret 6 cleanly while the ring finger holds fret 5 on the E string.
B7♭5/A inversion
B 7th flat 5 is played at the 7th fret as 8 9 7 8: middle finger on the G string at fret 8, pinky finger on the C string at fret 9, index finger on the E string at fret 7 and ring finger on the A string at fret 8.
Full note and interval breakdown
| String | Fret | Finger | Note |
|---|---|---|---|
| 4 (G) | 8 | 2 | D♯ (3) |
| 3 (C) | 9 | 4 | A (♭7) |
| 2 (E) | 7 | 1 | B (1) |
| 1 (A) | 8 | 3 | F (♭5) |
10th fret
B 7th flat 5 is played at the 10th fret as 10 11 11 12: index finger on the G string at fret 10, middle finger on the C string at fret 11, ring finger on the E string at fret 11 and pinky finger on the A string at fret 12.
Full note and interval breakdown
| String | Fret | Finger | Note |
|---|---|---|---|
| 4 (G) | 10 | 1 | F (♭5) |
| 3 (C) | 11 | 2 | B (1) |
| 2 (E) | 11 | 3 | D♯ (3) |
| 1 (A) | 12 | 4 | A (♭7) |
B7♭5/D♯ inversion
B 7th flat 5 is played at the 1st fret as 2 3 1 2: middle finger on the G string at fret 2, pinky finger on the C string at fret 3, index finger on the E string at fret 1 and ring finger on the A string at fret 2.
Full note and interval breakdown
| String | Fret | Finger | Note |
|---|---|---|---|
| 4 (G) | 2 | 2 | A (♭7) |
| 3 (C) | 3 | 4 | D♯ (3) |
| 2 (E) | 1 | 1 | F (♭5) |
| 1 (A) | 2 | 3 | B (1) |
Why it sounds like that
B 7th flat 5 uses the formula 1, 3, ♭5, ♭7. The diminished 5th between B and F gives the chord its tense color. Compare it to B 7th, which raises that F to F♯.
What goes wrong with B 7th flat 5?
- Letting the pinky flatten onto the A string, which buzzes the note.
- Pressing the ring finger too far across, deadening the C string.
- Strumming before the middle finger is fully seated on the C string.
When to use it
B 7th flat 5 works as a tense dominant in B major, especially moving to B major or B 5th. Its altered fifth suits jazz and funk lines where a plain B 7th sounds too settled.
Changing to and from B 7th flat 5
- Sliding the shape down two frets to the 2nd fret gives A 7th flat 5.
- Sliding the shape up one fret to the 5th fret gives C 7th flat 5.
Which voicing to use
The 4th fret position keeps B in the bass for a root-position sound. The B7♭5/D♯ inversion at the 8th fret puts the major third in the bass, while the B7♭5/F inversion at the 10th fret emphasizes the ♭5.
Other B chords
Common questions
How is B 7th flat 5 written?
B 7th flat 5 is written as B7♭5 or B. The symbol B7♭5 is the most common.
What is the difference between B 7th flat 5 and B 7th?
B 7th flat 5 lowers the fifth from F♯ to F, creating a diminished fifth. B 7th keeps the perfect fifth F♯.
Why does B 7th flat 5 sound unstable?
The diminished fifth between B and F is a tritone, which wants to resolve. This tension makes the chord useful before a tonic.