Dorian b5 is a minor scale with the Dorian natural 6 but a flatted 5th. It combines the jazzy character of Dorian with the instability of a diminished 5th - a rare and interesting sound for half-diminished contexts.
Scale Formula
1 2 b3 4 b5 6 b7 - Dorian with flat 5. Semitone pattern: W H W H WH H W
Fretboard (C Dorian b5)
Toggle to interval view to spot the b5 and natural 6 - these two intervals together distinguish Dorian b5 from regular Dorian and from Locrian.
Common Chords
Half-diminished 7th (1 b3 b5 b7), Minor 7b5 (1 b3 b5 b7).
Diatonic Harmony
Improvisation Context
Play over half-diminished (m7b5) chords. An alternative to Locrian #2 with a different flavor - the natural 6 provides a distinctive brightness against the b5.
Characteristic Note
The natural 6 combined with the b5 is what sets this mode apart. Regular Dorian has a natural 5, and Locrian has a b6 - Dorian b5 splits the difference with a diminished 5th but a bright natural 6th. The natural 6 adds unexpected warmth to what would otherwise be a fully dark half-diminished sound.
Practice
Play C Dorian b5 over a Cm7b5 drone. Compare it with C Locrian (b2 b3 4 b5 b6 b7) to hear how the natural 2 and natural 6 brighten the half-diminished sound. Then compare with regular C Dorian - the single b5 change makes the mode unstable but the natural 6 keeps it from being as dark as Locrian. Improvise lines that highlight the 6 resolving to the b5.