Understand and Play the C 9b5 Chord on Guitar

The C9b5 chord, or C ninth flat five, is spelled C, E, Gb, Bb and D. Take C7b5 (C, E, Gb, Bb) and put the D, a major ninth, on top: the chord keeps its tritone tension and gains a little more colour.

Three voicings are listed, all of them barres, the lowest at the 2nd fret. The D is also the second step of the C whole-tone scale, and that scale contains every note of the chord, so it is the obvious source for melodic ideas over C9b5.

Press play above to hear the chord strummed, then as an arpeggio.

C 9th with flat 5th guitar chord is also written as C9b5, C9(b5) or C9-5.

Notes of the C 9b5 chord:

C E Gb Bb D

Tones in the Dominant Ninth Flat five chord:

Formula: 1 3 b5 b7 9

C 9b5 Chord Interactive Fretboard

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C 9b5 Guitar Chord Diagrams

Position 1 Barre Movable

Finger Positions

Place your index finger (1) on the fret 2 of the low E, D and high E strings at the same time
Place your middle finger (2) on the fret 3 of the A string
Place your ring finger (3) on the fret 3 of the G string
Place your pinky finger (4) on the fret 3 of the B string

Position 2 Barre Movable

Finger Positions

Place your index finger (1) on the fret 7 of the A, G and B strings at the same time
Place your middle finger (2) on the fret 8 of the low E string
Place your ring finger (3) on the fret 8 of the D string
Place your pinky finger (4) on the fret 8 of the high E string

Position 3 Barre Movable

Finger Positions

Mute the low E string
Mute the A string
Place your index finger (1) on the fret 10 of the D and high E strings at the same time
Place your middle finger (2) on the fret 11 of the G string
Place your ring finger (3) on the fret 11 of the B string

Find more shapes in our all guitar chords online library. If you prefer a printable pdf, download the Free Guitar Chords Chart Pdf

Play This Chord With Other Roots

C 9b5 | D 9b5 | E 9b5 | F 9b5 | G 9b5 | A 9b5 | B 9b5 | C#9b5 | D#9b5 | F#9b5 | G#9b5 | A#9b5 | Ab9b5 | Bb9b5 | Db9b5 | Eb9b5 | Gb9b5

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Created by

Giancarlo Facoetti

Giancarlo is a musician (teaching guitar since 2000), software engineer, AI consultant and published researcher

FAQ

What notes are in C9b5?

C9b5 contains C, E, Gb, Bb and D. It is C9 with the fifth lowered from G to Gb.

Which scale pairs with C ninth flat five?

The C whole-tone scale is C, D, E, F#, G# and Bb. It holds all five chord pitches, with the chord's Gb written as F#.

What do the b5 and 9 mean in C9b5?

The b5 is Gb, a diminished fifth over C. The 9 is D, a major ninth over C, or the second degree an octave higher.

How many C9b5 voicings are there?

There are 3 voicings, from fret 2 to fret 11. All 3 are barre voicings and none uses an open string.

How is C9b5 different from C7b5?

C7b5 has C, E, Gb and Bb. C9b5 keeps them and adds D, the ninth, for a fifth note.