C#maj13b5 Major 7th
The C#maj13b5 chord is built from the notes C# – E# – G – B# – D# – A#.
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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).
D#Extension
Ninth (9)
A 9th — colorful extension a whole step above the octave.
A#Extension
Thirteenth (13)
A 13th — full, rich top extension.
🎼 Related scales
🎹 Modal analysis
This chord implies the Lydian scale; its characteristic note is the bright, floating ♯11.
🎸 Genres
Film & TV scoring · Modal jazz · Impressionism