Fm7b5

Fm7b5 is F, Ab, Cb and Eb, a half-diminished seventh. The shape this page opens on is written 1x110x, lowest string first.

Note by note. F is the root, Ab is the minor third, Cb is the flat fifth and Eb is the flat seventh.

Also written Fø, Fø7, Fm7-5, Fm7(b5) or F half diminished. The same chord either way; which spelling you meet depends on who wrote the chart.

There are 9 common shapes for Fm7b5 on the guitar, and 28 derived voicings in 3 families.

One note away. Change a single note of Fm7b5 and you have Fdim (with one note taken away), Fdim7 (with one note moved), Fm7 (with one note moved), FmMaj7b5 (with one note moved) or F7b5 (with one note moved).

In which keys. Every note of Fm7b5 belongs to Eb minor (the ii°) and F# major (the vii°).

The common shapes, written lowest string first: 1x110x, 123141, xx3444, x86867, x8989x, x-x-9-10-9-11, 13-11-13-13-0-x, 13-x-x-13-12-11, 13-x-13-13-12-x.

Under the hand. 1 of the 9 shapes here sits in open position, and the first uses 1 open string with 2 left unplayed. 5 of the 9 need a barre. Together they cover the neck from the 1st fret to the 13th.

Where it goes. Fm7b5 is the ii of Eb minor, which is where it is nearly always found: half-diminished, then an altered dominant, then the minor tonic.

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. Fm7b5 has 1x110x, x8x897, 13-x-13-13-12-x, 1664xx, x-8-13-13-12-x.

Drop 2. A close-position chord with the second voice from the top lowered an octave. Sits on four adjacent strings. Fm7b5 has xx1101, 1211xx, xx3444, x6646x, 7868xx, xx6867, x8989x, x-x-9-10-9-11.

Drop 3. The third voice from the top lowered an octave. The dropped voice becomes the bass, which is why a string is skipped. Fm7b5 has x2x141, 1x110x, 4x344x, x6x464, 7x686x, x8x897, 11-x-9-10-9-x, x-11-x-10-12-11.

Tensions. A shell of Fm7b5, root, third and seventh, leaves a string free, and the tones that belong over it are the 11 (Bb) and the b13 (Db).

What kind of chord this is. Fm7b5 is a diminished chord — root, minor third, flat fifth. diminished and half-diminished 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.