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C♯ augmented major 7th chord on bass (C♯augMaj7)
Also called or written C♯augMaj7, C♯augM7, C♯+M7, C♯M7#5, C♯maj+7, C♯ augmented major seventh or C♯ major seventh sharp five
C♯ augmented major 7th is built from C♯, E♯, G♯♯ and B♯. The default voicing requires a wide stretch and careful intonation on the high frets.
How it is built
Formula 1, 3, ♯5, 7
How do you play a C♯ augmented major 7th chord on bass?
C♯ augmented major 7th is played at the 3rd fret as 5 4 3 5: ring finger on the E string at fret 5, middle finger on the A string at fret 4, index finger on the D string at fret 3 and pinky finger on the G string at fret 5.
Full note and interval breakdown
| String | Fret | Finger | Note |
|---|---|---|---|
| 4 (E) | 5 | 3 | G♯♯ (♯5) |
| 3 (A) | 4 | 2 | C♯ (1) |
| 2 (D) | 3 | 1 | E♯ (3) |
| 1 (G) | 5 | 4 | B♯ (7) |
AdvancedThe pinky must reach the 5th fret on the 1st string while the index holds the 3rd fret on the 2nd string, creating a wide stretch.
C♯augM7/B♯ inversion
C♯ augmented major 7th is played at the 6th fret as 8 8 7 6: ring finger on the E string at fret 8, pinky finger on the A string at fret 8, middle finger on the D string at fret 7 and index finger on the G string at fret 6.
Full note and interval breakdown
| String | Fret | Finger | Note |
|---|---|---|---|
| 4 (E) | 8 | 3 | B♯ (7) |
| 3 (A) | 8 | 4 | E♯ (3) |
| 2 (D) | 7 | 2 | G♯♯ (♯5) |
| 1 (G) | 6 | 1 | C♯ (1) |
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.
Other C♯ chords
Common questions
How is C♯ augmented major 7th written?
C♯ augmented major 7th is written C♯+M7, M7#5, maj+7, or C♯augM7. The ASCII root is C#. It is also spelled D♭ in enharmonic notation for the same sounding root.
What is the difference between C♯ augmented major 7th and C♯ major 7th?
C♯ augmented major 7th has a raised fifth G♯♯, while C♯ major 7th has a perfect fifth G♯. The raised fifth creates a more dissonant, unstable sound.
Why does C♯ augmented major 7th use a double sharp?
The fifth of C♯ is G♯, so raising it a semitone gives G♯♯, which is enharmonically A. The double sharp keeps the interval name consistent with the scale degree.