B augmented major 7th chord on bass (BaugMaj7)

Why it sounds like that

B augmented major 7th is built as 1–3–♯5–7, with major thirds between B and D♯, and D♯ and F♯♯. The double-sharped fifth F♯♯ (enharmonically G) gives the chord its augmented colour, while the major seventh A♯ adds brightness. Compare B major 7th, which has a perfect fifth F♯.

What goes wrong with B augmented major 7th?

• Letting the index finger mute the 3rd string while fretting the 2nd.
• Pressing too hard with the pinky, causing the 1st string to go sharp.

When to use it

B augmented major 7th works as a passing chord between B major and E♭ major, or as a substitute for B major 7th in jazz. Its tight, bright sound suits bebop and modern jazz.

Changing to and from B augmented major 7th

• Sliding the shape up one fret to the 2nd fret gives C augmented major 7th.
• Sliding the shape up two frets to the 3rd fret gives C♯ augmented major 7th.

Which voicing to use

The F♯♯ inversion places the augmented fifth in the bass, creating a tense, leading tone. The A♯ inversion puts the major seventh in the bass, which darkens the chord and works well for descending lines.