Bbdim7(b9) Diminished
The Bbdim7(b9) chord is built from the notes Bb – Db – Fb – Abb – Cb.
Piano sound loads on first tap.
Also known as
Bbdim7addb9Bbo(addb9)Bbo7(addb5b9)Bbo7(b9)
Chord tones, one by one
BbRoot
Root
The fundamental note the chord is built on — Bb.
DbThird
Minor third
Three semitones — makes the chord minor (darker, sadder).
FbFifth
Diminished fifth (♭5)
Six semitones — a flat fifth. Creates instability, typical of m7♭5 and diminished chords.
AbbSeventh
Diminished seventh (♭♭7)
Nine semitones — a doubly-flat seventh, found in fully diminished 7th chords.
CbExtension
Flat ninth (♭9)
A ♭9 — sharp, dissonant tension typical of altered dominant chords.
🎼 Related scales
Locrian ♮6harmonic minor a semitone below
🎹 Modal analysis
This chord implies the Locrian ♮6 scale; its characteristic note is the natural 6th over a diminished chord. It is a mode of the harmonic minor a semitone below.
🎸 Genres
Modern jazz · Post-bop · Fusion