C#ma7b5b9 Major 7th
The C#ma7b5b9 chord is built from the notes C# – E# – G – B# – D.
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Also known as
C#maj7b5b9
Chord tones, one by one
C#Root
Root
The fundamental note the chord is built on — C#.
E#Third
Major third
Four semitones — makes the chord major (brighter, happier).
GFifth
Diminished fifth (♭5)
Six semitones — a flat fifth. Creates instability, typical of m7♭5 and diminished chords.
B#Seventh
Major seventh
Eleven semitones — a lush, jazzy seventh just below the octave (maj7).
DExtension
Flat ninth (♭9)
A ♭9 — sharp, dissonant tension typical of altered dominant chords.
🎼 Related scales
🎹 Modal analysis
This chord implies the Lydian ♭2 scale; its characteristic note is the ♭9 / ♭2.
🎸 Genres
Modern jazz · Post-bop · Fusion