Bm(maj9b5b9) Diminished

The Bm(maj9b5b9) chord is built from the notes B – D – F – A# – C – C#.

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Chord tones, one by one

BRoot

Root

The fundamental note the chord is built on — B.

DThird

Minor third

Three semitones — makes the chord minor (darker, sadder).

FFifth

Diminished fifth (♭5)

Six semitones — a flat fifth. Creates instability, typical of m7♭5 and diminished chords.

A#Seventh

Major seventh

Eleven semitones — a lush, jazzy seventh just below the octave (maj7).

CExtension

Flat ninth (♭9)

A ♭9 — sharp, dissonant tension typical of altered dominant chords.

C#Extension

Ninth (9)

A 9th — colorful extension a whole step above the octave.

🎹 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

m(maj9b5b9) in every key

More B chords