Ab7b5

Ab7b5 is Ab, C, D and Gb, a seven flat five. The shape this page opens on is written 4x453x, lowest string first.

Note by note. Ab is the root, C is the major third, D is the flat fifth and Gb is the flat seventh.

Also written Ab7(b5), Ab7-5 or Ab7♭5. The same chord either way; which spelling you meet depends on who wrote the chart.

There are 5 common shapes for Ab7b5 on the guitar, and 35 derived voicings in 4 families.

One note away. Change a single note of Ab7b5 and you have Abmaj7b5 (with one note moved), Abm7b5 (with one note moved), Ab7 (with one note moved), Abaug7 (with one note moved) or Ab9b5 (with one note added).

The common shapes, written lowest string first: 4x453x, xx6778, x-9-10-11-9-10, x-x-10-11-9-10, x-11-12-11-13-x.

Under the hand. None of the shapes for Ab7b5 uses an open string, so every one of them is movable; the lowest sits at the 3rd fret. None of them needs a barre. Together they cover the neck from the 3rd fret to the 13th.

Where it goes. Ab7b5 is a dominant with its tension raised, so it still points at Db — harder than a plain seventh does, because the altered tones sit a semitone from where they are going.

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. Ab7b5 has 4x453x, 4347xx, x-11-x-11-13-10, x-x-6-5-7-10, x-11-10-11-15-x.

Drop 2. A close-position chord with the second voice from the top lowered an octave. Sits on four adjacent strings. Ab7b5 has xx0112, 2301xx, xx4534, 4545xx, x5657x, xx6778, x-x-10-11-9-10, 10-11-10-11-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. Ab7b5 has x3x132, 2x011x, 4x453x, x5x574, 8x677x, x9x798, 10-x-10-11-9-x, x-11-x-11-13-10.

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. Ab7b5 has 454500, 4x4530, x56570, 20050x, 2x0500, xx0570.

Tensions. A shell of Ab7b5, root, third and seventh, leaves a string free, and the tones that belong over it are the b9 (Bbb), the 9 (Bb), the #9 (B), the b13 (Fb) and the 13 (F).

What kind of chord this is. Ab7b5 is an altered chord — a dominant seventh with its fifth or ninth moved. altered dominant chords on every root, and what they are for.

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