C9#11

C9#11 is C, E, G, Bb, D and F#, a nine sharp eleven. The shape this page opens on is written x32332, lowest string first.

Also written C9(#11), C9+11 or C9♯11. The same chord either way; which spelling you meet depends on who wrote the chart.

There are 6 common shapes for C9#11 on the guitar, and 26 derived voicings in 3 families.

The common shapes, written lowest string first: x32332, x3435x, 878778, 8x897x, 898988, x-x-10-11-11-12.

Shell. Root, third and seventh: the guide tones fix the quality, so the fifth is dropped. That is what leaves a string free, so pick a tension to put on top. C9#11 has x3233x, 8787xx, x-x-10-9-11-10, x-15-14-15-15-x, x3x352, 8x897x, 8-7-8-11-x-x, x3237x.

Rootless. The root left to the bass player. Frees a finger for a tension. C9#11 has xx2332, x5435x, x7877x, x-x-12-11-11-12, x-x-14-15-15-14, x5x352, xx4756, x7x776.

Open string. An open string left ringing against a fretted grip. Because it costs no finger, it sounds a note the closed shape has none left for -- a tension on top, or a pedal root underneath. Either a familiar grip with open strings added, or a shape so sparse the open strings carry the chord. These belong to their key rather than to a shape, so D, A, G and E have many and Eb a handful. C9#11 has 004756, 030352, 0x0076, 6x0070.

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).

The common shapes and the derived voicings come from different places, and both are explained in where the chords and the theory come from.