C9 chord on electric guitar
C9 is the dominant ninth chord: C, E, G, Bb and D (1–3–5–b7–9). On electric guitar, the diagram shape is 0 1 0 0 1 0, with E in the bass.
On the electric guitar a chord needs only a few clear notes — the amp sustains them and fills the space, so you mute the strings you are not playing and let the tone carry the rest. In this C9 voicing the bass is E and the shape sits at fret 1, ringing 4 open strings. Plugged into an amp, each chord sustains for as long as you hold it, and the tone — clean or driven — shapes the whole sound.
Notes and formula of C9
Notes in C9: C – E – G – Bb – DFormula: 1 – 3 – 5 – b7 – 9In the formula, the numbers count steps of the major scale starting from the note that names the chord; "b" lowers a half step, "#" raises one — and a slash names the bass note.
Where to use it
Blues, funk, choro and broader dominants.
See also
Part of the Extended family.