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C minor 7th flat 5th chord on bass (Cm7♭5)
Also called or written Cm7♭5, C or C Half Diminished Minor 7
C minor 7th flat 5th contains C, E♭, G♭ and B♭. The 8th-fret shape 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 minor 7th flat 5th chord on bass?
C minor 7th flat 5th is played at the 8th fret as 8 9 8 8: index finger on the E string at fret 8, pinky finger on the A string at fret 9, middle finger on the D string at fret 8 and ring finger on the G string at fret 8.
Full note and interval breakdown
| String | Fret | Finger | Note |
|---|---|---|---|
| 4 (E) | 8 | 1 | C (1) |
| 3 (A) | 9 | 4 | G♭ (♭5) |
| 2 (D) | 8 | 2 | B♭ (♭7) |
| 1 (G) | 8 | 3 | E♭ (♭3) |
AdvancedThe wide stretch between the index finger on the 4th string and the pinky on the 3rd string at the 8th fret is the hardest part.
Cm7♭5/G♭ inversion · fret 1
C minor 7th flat 5th is played at the 1st fret as 2 3 1 3: middle finger on the E string at fret 2, ring finger on the A string at fret 3, index finger on the D string at fret 1 and pinky finger on the G string at fret 3.
Full note and interval breakdown
| String | Fret | Finger | Note |
|---|---|---|---|
| 4 (E) | 2 | 2 | G♭ (♭5) |
| 3 (A) | 3 | 3 | C (1) |
| 2 (D) | 1 | 1 | E♭ (♭3) |
| 1 (G) | 3 | 4 | B♭ (♭7) |
Cm7♭5/G♭ inversion · fret 13
C minor 7th flat 5th is played at the 13th fret as 14 15 13 15: middle finger on the E string at fret 14, ring finger on the A string at fret 15, index finger on the D string at fret 13 and pinky finger on the G string at fret 15.
Full note and interval breakdown
| String | Fret | Finger | Note |
|---|---|---|---|
| 4 (E) | 14 | 2 | G♭ (♭5) |
| 3 (A) | 15 | 3 | C (1) |
| 2 (D) | 13 | 1 | E♭ (♭3) |
| 1 (G) | 15 | 4 | B♭ (♭7) |
Cm7♭5/B♭ inversion
C minor 7th flat 5th is played at the 4th fret as 6 6 4 5: ring finger on the E string at fret 6, pinky finger on the A string at fret 6, index finger on the D string at fret 4 and middle finger on the G string at fret 5.
Full note and interval breakdown
| String | Fret | Finger | Note |
|---|---|---|---|
| 4 (E) | 6 | 3 | B♭ (♭7) |
| 3 (A) | 6 | 4 | E♭ (♭3) |
| 2 (D) | 4 | 1 | G♭ (♭5) |
| 1 (G) | 5 | 2 | C (1) |
Why it sounds like that
C minor 7th flat 5th is built from the formula 1, ♭3, ♭5, ♭7. The diminished 5th between C and G♭ creates the chord's characteristic tension. Raising the ♭5 to a perfect 5th produces C minor 7th, the closest stable contrast.
What goes wrong with C minor 7th flat 5th?
- Letting the pinky collapse and mute the 2nd string.
- Fretting the 1st string with the ring finger too far from the fret, causing a buzz.
- Allowing the index finger to touch the 3rd string and deaden the C.
When to use it
C minor 7th flat 5th functions as the ii chord in B♭ natural minor and the vii chord in C♯ major. Use it in minor-key jazz and blues lines where the half-diminished colour leads to a dominant. It pairs naturally with C minor and C 5th.
Changing to and from C minor 7th flat 5th
- Sliding the shape down one fret to the 7th fret gives B minor 7th flat 5th.
- Sliding the shape up one fret to the 9th fret gives C♯ minor 7th flat 5th.
Which voicing to use
The 8th-fret root position keeps C in the bass for a grounded sound. The Cm7♭5/G♭ inversion at the 2nd fret places the diminished 5th in the bass, creating a darker, less stable feel. Choose the Cm7♭5/B♭ inversion when the bass line needs to descend to B♭.
Other C chords
Common questions
How is C minor 7th flat 5th written?
C minor 7th flat 5th is written as Cm7♭5, and it is also called Half Diminished Minor 7.
What is the difference between C minor 7th flat 5th and C diminished?
C minor 7th flat 5th adds a minor 7th to the diminished triad. C diminished has only the root, ♭3 and ♭5.
Why does C minor 7th flat 5th sound unstable?
The tritone between C and G♭ creates tension that wants to resolve. This instability makes the chord useful as a passing harmony.