Dm7b5 is D, F, Ab and C — with the fifth lowered a semitone.
It sounds hollow, and unmistakably going somewhere. It walks straight into an altered dominant, which is where you will nearly always meet it.
Pre-dominant — the ii of a minor key.
Also written Dø, Dø7, Dm7-5, Dm7(b5) or D half diminished.
In a minor key the ii chord is half-diminished, and Dm7b5 leads to the V and on to the i. Its flat fifth is the key’s flat sixth: it holds as the dominant’s flat nine, then falls to the fifth of the home chord, whether that chord is minor or major.
Listen for: The flat fifth holds over the barline as the dominant’s flat nine, then falls a half step to the fifth.
Heard in“There Will Never Be Another You”“Night and Day”, resolving to major
In a major key Dm7b5 is built on the leading tone and does the dominant’s job. Lower its seventh a whole step and it becomes Bb7; its bass, the leading tone, then rises into the root of Eb.
Listen for: Only the seventh moves at first, down a whole step, and the chord is the V7. That note then holds as the fifth of the I.
In the basic turnaround in F minor, Dm7b5 is the second chord, between the i and the ii.
A turnaround in B♭ major can start on the iii instead of the I, and that iii can be played as Dm7b5, in front of an altered VI7.
In which keys. Every note of Dm7b5 belongs to C minor and Eb major.
Every note of Dm7b5 is in D blues, D locrian, D altered and D half-whole diminished.
Each of those is a page: the scale across the neck, and the chords it harmonises into — which is where Dm7b5 sits in it. Every scale.
Change one note of Dm7b5 and you have (drop the flat seventh), (the flat seventh becomes the diminished seventh), (the flat fifth becomes the fifth), (the flat seventh becomes the major seventh) or (the minor third becomes the major third).
Dm7b5 is a diminished chord — root, minor third, flat fifth. Diminished and half-diminished chords on every root.
The common shapes and the derived voicings come from different places, and both are explained in how this site is built.
Shows each chord the way this style would voice it, and marks which of its alternatives belong to the idiom.