C9#11 guitar chord
The root left to the bass player. Frees a finger for a tension.
- Tap a note to hear it
- Arrows change position
- Fingers, notes or intervals
- Play the chord
About C9#11 — rootless voicings
C9#11 is C, E, G, Bb, D and F# — C9 with the raised eleventh added on top.
It sounds wide and glassy, bright rather than tense. The ♯11 clears the major third by a whole step, so it adds height without the collision a natural eleventh makes.
C9#11 notes and formula
| C | E | G | Bb | D | F# |
|---|---|---|---|---|---|
| 1 | 3 | 5 | ♭7 | 9 | ♯11 |
Dominant — the lydian dominant sound.
Also written C9(#11), C9+11 or C9♯11. The same chord either way; which spelling you meet depends on who wrote the chart.
How to play C9#11
Leave the root to the bass player. In a band nobody misses it, and the ear supplies it from the guide tones anyway.
The finger it frees goes to a tension, which is why these sound richer than the shape they came from rather than thinner.
C9#11 has 13 of them, on the top four strings, the middle four strings and strings 5-3-2-1, from the 2nd fret up to the 14th — every inversion the chord has: E in the bass, Bb in the bass, D in the bass and F# in the bass. The one to learn first is the E shape at the 2nd fret, which is the easiest grip here.
5 of them sit on the top four strings, so you can run the inversions up one set without changing strings — which is the whole reason to learn them as a family rather than as separate grips.
Start with x3435x — no barre and low, at the 3rd fret. None of the shapes for C9#11 uses an open string, so every one of them is movable; the lowest sits at the 2nd fret. 3 of the 6 need a barre. Together they cover the neck from the 2nd fret to the 12th.
| Frets | Where | Bass | Top | Hand |
|---|---|---|---|---|
| x32332 | 2nd fret | C, root position | F# | barred |
| x3435x | 3rd fret | C, root position | E | all fretted |
| 878778 | 7th fret | C, root position | C | barred |
| 8x897x | 7th fret | C, root position | F# | all fretted |
| 898988 | 8th fret | C, root position | C | barred |
| x-x-10-11-11-12 | 10th fret | C, root position | E | all fretted |
The same notes rebuilt from scratch give 9 shell and 4 open string voicings, each on its own page.
Tensions. A shell of C9#11, root, third and seventh, leaves a string free, and the tones that belong over it are the b13 (Ab) and the 13 (A).
How to use C9#11
C9#11 is a dominant with its tension raised, so it still points at F — harder than a plain seventh does, because the altered tones sit a semitone from where they are going.
Voice by voice, C9#11 → F. 3 voices move by a semitone, and one note is common to both chords.
| In C9#11 | Moves | In F |
|---|---|---|
| C, the root | stays where it is | C, the fifth |
| E, the major third | rises a semitone | F, the root |
| G, the fifth | falls a whole tone | F, the root |
| Bb, the flat seventh | falls a semitone | A, the major third |
| D, the ninth | falls a whole tone | C, the fifth |
| F#, the sharp eleventh | falls a semitone | F, the root |
What to play over C9#11
Every note of C9#11 is in C lydian dominant.
Chords near C9#11
Change one note of C9#11 and you have C9 (drop the flat fifth), C9b5 (drop the fifth) or C13 (the flat fifth becomes a sixth).
C9#11 is an altered chord — a dominant seventh with its fifth or ninth moved. Altered dominant chords on every root.
On C9#11’s sound and use this page follows Mark Levine, The Jazz Theory Book (Sher Music, 1995). The shapes and the derived voicings come from different places, and both are explained in where the chords and the theory come from.