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C 7th flat 5 chord on bass (C7♭5)
Also called or written C7♭5, C, C Dominant 7th Flat 5 or C 7th ♭5
C 7th flat 5 contains C, E, G♭ and B♭. The 8th-fret shape places the root high on the neck, where the frets are close and the stretch is manageable.
How it is built
Formula 1, 3, ♭5, ♭7
How do you play a C 7th flat 5 chord on bass?
C 7th flat 5 is played at the 8th fret as 8 9 8 9: index finger on the E string at fret 8, ring finger on the A string at fret 9, middle finger on the D string at fret 8 and pinky finger on the G string at fret 9.
Full note and interval breakdown
| String | Fret | Finger | Note |
|---|---|---|---|
| 4 (E) | 8 | 1 | C (1) |
| 3 (A) | 9 | 3 | G♭ (♭5) |
| 2 (D) | 8 | 2 | B♭ (♭7) |
| 1 (G) | 9 | 4 | E (3) |
AdvancedThe 8th-fret shape requires the pinky to reach fret 9 on the 1st string while the index holds fret 8 on the 4th string, stretching the left hand.
C7♭5/G♭ inversion · fret 2
C 7th flat 5 is played at the 2nd fret as 2 3 2 3: index finger on the E string at fret 2, ring finger on the A string at fret 3, middle finger on the D string at fret 2 and pinky finger on the G string at fret 3.
Full note and interval breakdown
| String | Fret | Finger | Note |
|---|---|---|---|
| 4 (E) | 2 | 1 | G♭ (♭5) |
| 3 (A) | 3 | 3 | C (1) |
| 2 (D) | 2 | 2 | E (3) |
| 1 (G) | 3 | 4 | B♭ (♭7) |
C7♭5/G♭ inversion · fret 14
C 7th flat 5 is played at the 14th fret as 14 15 14 15: index finger on the E string at fret 14, ring finger on the A string at fret 15, middle finger on the D string at fret 14 and pinky finger on the G string at fret 15.
Full note and interval breakdown
| String | Fret | Finger | Note |
|---|---|---|---|
| 4 (E) | 14 | 1 | G♭ (♭5) |
| 3 (A) | 15 | 3 | C (1) |
| 2 (D) | 14 | 2 | E (3) |
| 1 (G) | 15 | 4 | B♭ (♭7) |
Why it sounds like that
C 7th flat 5 is built from the formula 1, 3, ♭5, ♭7. The diminished 5th between C and G♭ defines its unstable quality. Compare it with C 7th, which has a perfect 5th.
What goes wrong with C 7th flat 5?
- Letting the pinky collapse on the 1st string, which mutes the B♭ at fret 9.
- Pressing the ring finger too flat on the 3rd string, so it deadens the 2nd string next to it.
- Striking the open 5th string, which is not part of the chord and adds an unwanted C.
When to use it
C 7th flat 5 functions as a dominant chord in F minor or as a passing chord in jazz. It can substitute for C 7th when the ♭5 is needed. Its tense sound fits bebop and fusion lines.
Changing to and from C 7th flat 5
- Move to B♭ 7th flat 5 by sliding the shape down two frets to the 6th fret.
- Move to C♯ 7th flat 5 by sliding the shape up one fret to the 9th fret.
Which voicing to use
The 8th-fret shape keeps C in the bass for a root-position sound. The C7♭5/G♭ inversion at fret 2 or 14 puts the ♭5 in the bass, creating a darker, less stable feel.
Other C chords
Common questions
How is C 7th flat 5 written?
C 7th flat 5 is written C7♭5 or C. The symbol C is also used, and the chord is sometimes called Dominant 7th Flat 5.
What is the difference between C7♭5 and C7?
C7♭5 has a diminished 5th (G♭) instead of the perfect 5th (G) in C7. That one note changes the chord from bluesy to tense and unresolved.
Can C7♭5 be used in place of C7?
C7♭5 can replace C7 when the melody or solo uses the ♭5. In a standard blues, the ♭5 may clash with the expected perfect 5th, so use it selectively.