Ab7b9

Ab7b9 is Ab, C, Eb, Gb and A, a seven flat nine. The shape this page opens on is written x01112, lowest string first.

Also written Ab7(b9), Ab7-9 or Ab7♭9. The same chord either way; which spelling you meet depends on who wrote the chart.

There are 6 common shapes for Ab7b9 on the guitar, and 41 derived voicings in 5 families.

The common shapes, written lowest string first: x01112, 4342xx, xx4545, 464545, xx6575, x-11-10-11-10-11.

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. Ab7b9 has 4342xx, xx6575, x-11-10-11-10-x.

Drop 2. A close-position chord with the second voice from the top lowered an octave. Sits on four adjacent strings. Ab7b9 has 4342xx, xx6575, x-11-10-11-10-x, x0411x, xx4214, 5965xx, x9759x, 8-11-7-11-x-x.

Drop 3. The third voice from the top lowered an octave. The dropped voice becomes the bass, which is why a string is skipped. Ab7b9 has x0x112, 4x421x, 5x657x, x9x595, 8-x-7-11-9-x, x-11-x-11-10-8, 14-x-10-13-10-x, x-12-x-13-13-14.

Rootless. The root left to the bass player. Frees a finger for a tension. Ab7b9 has xx1212, x3424x, xx4545, x6757x, xx7878, x-9-10-8-10-x, x-x-10-11-10-11, x-12-13-11-13-x.

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. Ab7b9 has x34240, 5x6570, x00570, 2005xx.

Tensions. A shell of Ab7b9, root, third and seventh, leaves a string free, and the tones that belong over it are the #11 (D), the b13 (Fb) and the 13 (F).

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