C♯ augmented major 7th chord on bass (C♯augMaj7)

Why it sounds like that

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

What goes wrong with C♯ augmented major 7th?

• Letting the pinky collapse onto the 1st string, causing a buzz.
• Allowing the index finger to touch the 3rd string, deadening the E♯.

When to use it

C♯ augmented major 7th works as a passing chord between C♯ major and F major, or as a substitute for C♯ major 7th in jazz. Its bright, tense sound suits modern jazz and fusion.

Changing to and from C♯ augmented major 7th

• Sliding the shape down two frets to the 1st fret gives B augmented major 7th.
• Sliding the shape down one fret to the 2nd fret gives C augmented major 7th.

Which voicing to use

The G♯♯ inversion places the augmented fifth in the bass, creating a restless, upward-pulling sound. The B♯ inversion puts the major seventh in the bass, which darkens the chord and works well for descending bass lines.