Also written B♭7♭5, B♭ or B♭ Dominant 7th Flat 5
B♭ 7th flat 5 contains B♭, D, F♭, and A♭. The open E string gives this advanced chord a bright, ringing top.
The same three notes, with a different one in the bass.
B♭ 7th flat 5 is built from the formula 1, 3, ♭5, ♭7. The diminished 5th between B♭ and F♭ creates the chord's tense, unstable quality. Compare it to B♭ 7th, which has a perfect 5th instead.
B♭ 7th flat 5 works as a passing chord in jazz and blues, especially when moving to B♭ major or B♭ 7th. Its dissonant tritone suits moments of tension before a resolution.
The default B♭7♭5/D inversion puts D in the bass, giving a lighter, less grounded sound. For a darker feel, use the B♭7♭5/F♭ inversion with F♭ in the bass.
B♭ 7th flat 5 is played in open position as 1 2 0 1: index finger on the G string at fret 1, ring finger on the C string at fret 2 and middle finger on the A string at fret 1. The E string rings open.
Tip — The stretch between the index finger on the G string and the ring finger on the C string is wide for small hands.
| String | Fret | Finger | Note |
|---|---|---|---|
| 4 (G) | 1 | 1 | A♭ (♭7) |
| 3 (C) | 2 | 3 | D (3) |
| 2 (E) | open | — | F♭ (♭5) |
| 1 (A) | 1 | 2 | B♭ (1) |
B♭ 7th flat 5 is played at the 3rd fret as 3 4 4 5: index finger on the G string at fret 3, middle finger on the C string at fret 4, ring finger on the E string at fret 4 and pinky finger on the A string at fret 5.
| String | Fret | Finger | Note |
|---|---|---|---|
| 4 (G) | 3 | 1 | B♭ (1) |
| 3 (C) | 4 | 2 | F♭ (♭5) |
| 2 (E) | 4 | 3 | A♭ (♭7) |
| 1 (A) | 5 | 4 | D (3) |
B♭ 7th flat 5 is played at the 6th fret as 7 8 6 7: middle finger on the G string at fret 7, pinky finger on the C string at fret 8, index finger on the E string at fret 6 and ring finger on the A string at fret 7.
| String | Fret | Finger | Note |
|---|---|---|---|
| 4 (G) | 7 | 2 | D (3) |
| 3 (C) | 8 | 4 | A♭ (♭7) |
| 2 (E) | 6 | 1 | B♭ (1) |
| 1 (A) | 7 | 3 | F♭ (♭5) |
B♭ 7th flat 5 is played at the 9th fret as 9 10 10 11: index finger on the G string at fret 9, middle finger on the C string at fret 10, ring finger on the E string at fret 10 and pinky finger on the A string at fret 11.
| String | Fret | Finger | Note |
|---|---|---|---|
| 4 (G) | 9 | 1 | F♭ (♭5) |
| 3 (C) | 10 | 2 | B♭ (1) |
| 2 (E) | 10 | 3 | D (3) |
| 1 (A) | 11 | 4 | A♭ (♭7) |
B♭ 7th flat 5 is written as B♭7♭5 or B♭. The ASCII spelling is Bb. It is also spelled A♯ in enharmonic notation for the same sounding root.
B♭ 7th flat 5 has a diminished 5th (F♭), while B♭ 7th has a perfect 5th (F). The flat 5 creates more tension.
The open E string is the note D, which is the major 3rd of the chord. It is a chord tone and adds brightness.