Tools / Chords / C 7th flat 5

C 7th flat 5 chord on bass (C7♭5)

Also written C7♭5, C or C Dominant 7th Flat 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.

8th fret8-9-8-9

Positions on the neck1 of 3

How it’s built

C1Root

E3Major 3rd

G♭♭5Diminished 5th

B♭♭7Minor 7th

Formula 1, 3, ♭5, ♭7

Positions on the neck1 of 3

Inversions

The same three notes, with a different one in the bass.

Root positionC–E–G♭–B♭C7♭5Bass C

First inversionE–G♭–B♭–CC7♭5/EBass E

Second inversionG♭–B♭–C–EC7♭5/G♭Bass G♭

Third inversionB♭–C–E–G♭C7♭5/B♭Bass B♭

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.

How do you play a C 7th flat 5 chord on bass?

8th fret

Intermediate● On the diagram

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.

Tip — The 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.

String-by-string 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)

C7♭5/G♭ inversion · fret 2

Intermediate

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.

String-by-string 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

Intermediate

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.

String-by-string 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)

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.

String

Fret

Finger

Note

4 (E)

C (1)

3 (A)

G♭ (♭5)

2 (D)

B♭ (♭7)

1 (G)

E (3)

String

Fret

Finger

Note

4 (E)

G♭ (♭5)

3 (A)

C (1)

2 (D)

E (3)

1 (G)

B♭ (♭7)

String

Fret

Finger

Note

4 (E)

G♭ (♭5)

3 (A)

C (1)

2 (D)

E (3)

1 (G)

B♭ (♭7)