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C augmented major 7th chord on bass (CaugMaj7)
Also called or written CaugMaj7, CaugM7, C+M7, CM7#5, Cmaj+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 between the index and pinky fingers.
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 2nd fret as 4 3 2 4: ring finger on the E string at fret 4, middle finger on the A string at fret 3, index finger on the D string at fret 2 and pinky finger on the G string at fret 4.
Full note and interval breakdown
| String | Fret | Finger | Note |
|---|---|---|---|
| 4 (E) | 4 | 3 | G♯ (♯5) |
| 3 (A) | 3 | 2 | C (1) |
| 2 (D) | 2 | 1 | E (3) |
| 1 (G) | 4 | 4 | B (7) |
AdvancedThe pinky must reach the 4th fret on the 1st string while the index holds the 2nd fret on the 2nd string, creating a wide stretch.
CaugM7/B inversion
C augmented major 7th is played at the 5th fret as 7 7 6 5: ring finger on the E string at fret 7, pinky finger on the A string at fret 7, middle finger on the D string at fret 6 and index finger on the G string at fret 5.
Full note and interval breakdown
| String | Fret | Finger | Note |
|---|---|---|---|
| 4 (E) | 7 | 3 | B (7) |
| 3 (A) | 7 | 4 | E (3) |
| 2 (D) | 6 | 2 | G♯ (♯5) |
| 1 (G) | 5 | 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 raised fifth G♯ gives the chord its augmented tension, 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 E major, or as a substitute for C major 7th in jazz. Its bright, tense sound suits fusion and modern jazz.
Changing to and from C augmented major 7th
- Sliding the shape down one fret to the 1st fret gives B augmented major 7th.
- Sliding the shape up one fret to the 3rd 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 CaugM7. It is also called augmented major seventh or major seventh sharp five.
What is the difference between C augmented major 7th and C augmented?
C augmented major 7th adds the major seventh B to the augmented triad C–E–G♯. C augmented lacks the seventh, so it has less harmonic pull.
Why does C augmented major 7th sound unstable?
The augmented fifth G♯ creates a symmetrical division of the octave, leaving no clear tonal centre. The major seventh B adds further tension, making the chord want to resolve.