Bb-6(b9b13) Minor
The Bb-6(b9b13) chord is built from the notes Bb – Db – F – G – Cb – Gb.
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Chord tones, one by one
Root
The fundamental note the chord is built on — Bb.
Minor third
Three semitones — makes the chord minor (darker, sadder).
Perfect fifth
Seven semitones — the most stable interval, reinforces the root.
Thirteenth (13)
A 13th — full, rich top extension.
Flat ninth (♭9)
A ♭9 — sharp, dissonant tension typical of altered dominant chords.
Flat thirteenth (♭13)
A ♭13 — dark altered tension over a dominant chord.
🎹 Modal analysis
This chord is so rich it doesn't fit a single scale: it's a polychord (an “upper structure”) that stacks tensions from several scales at once. It doesn't work like a dominant that “wants” to resolve — it's pure color: picture one triad floating over an unrelated bass, the kind of sound used in reharmonization and modal passages. To make sense of it, follow the note-by-note breakdown above.
🎸 Genres
Modern jazz · Fusion · Film & TV scoring · Impressionism