Also written B♭augMaj7, B♭augM7 or B♭+M7
B♭ augmented major 7th is built from B♭, D, F♯ and A. The default voicing uses two open strings, making it easier to fret but harder to control.
The same three notes, with a different one in the bass.
B♭ augmented major 7th follows the formula 1–3–♯5–7, stacking major thirds from B♭ to D to F♯. The raised fifth F♯ gives the chord its augmented tension, while the major seventh A adds brightness. Compare B♭ major 7th, which has a perfect fifth F.
B♭ augmented major 7th works as a passing chord between B♭ major and D major, or as a substitute for B♭ major 7th in jazz. Its open-string resonance suits folk-influenced jazz and atmospheric ballads.
The F♯ inversion places the augmented fifth in the bass, giving a bright, cutting edge. The A inversion puts the major seventh in the bass, which softens the chord and works well for descending bass lines.
B♭ augmented major 7th is played in open position as 2 0 0 3: index finger on the E string at fret 2 and middle finger on the G string at fret 3. The A and D strings ring open.
Tip — The open strings can ring too loudly, drowning out the fretted notes if the right hand is not controlled.
| String | Fret | Finger | Note |
|---|---|---|---|
| 4 (E) | 2 | 1 | F♯ (♯5) |
| 3 (A) | open | — | A (7) |
| 2 (D) | open | — | D (3) |
| 1 (G) | 3 | 2 | B♭ (1) |
B♭ augmented major 7th is played in open position as 2 1 0 2: middle finger on the E string at fret 2, index finger on the A string at fret 1 and ring finger on the G string at fret 2. The D string rings open.
| String | Fret | Finger | Note |
|---|---|---|---|
| 4 (E) | 2 | 2 | F♯ (♯5) |
| 3 (A) | 1 | 1 | B♭ (1) |
| 2 (D) | open | — | D (3) |
| 1 (G) | 2 | 3 | A (7) |
B♭ augmented major 7th is played at the 12th fret as 14 13 12 14: ring finger on the E string at fret 14, middle finger on the A string at fret 13, index finger on the D string at fret 12 and pinky finger on the G string at fret 14.
| String | Fret | Finger | Note |
|---|---|---|---|
| 4 (E) | 14 | 3 | F♯ (♯5) |
| 3 (A) | 13 | 2 | B♭ (1) |
| 2 (D) | 12 | 1 | D (3) |
| 1 (G) | 14 | 4 | A (7) |
B♭ augmented major 7th is played at the 3rd fret as 5 5 4 3: ring finger on the E string at fret 5, pinky finger on the A string at fret 5, middle finger on the D string at fret 4 and index finger on the G string at fret 3.
| String | Fret | Finger | Note |
|---|---|---|---|
| 4 (E) | 5 | 3 | A (7) |
| 3 (A) | 5 | 4 | D (3) |
| 2 (D) | 4 | 2 | F♯ (♯5) |
| 1 (G) | 3 | 1 | B♭ (1) |
B♭ augmented major 7th is written B♭+M7, M7#5, maj+7, or B♭augM7. The ASCII root is Bb. It is also spelled A♯ in enharmonic notation for the same sounding root.
B♭ augmented major 7th adds the major seventh A to the augmented triad B♭–D–F♯. B♭ augmented lacks the seventh, so it has less harmonic pull.
The open A and D strings are chord tones, so they are left open to create a fuller sound. This makes the chord easier to fret but requires careful right-hand control.