C#m7b5add9 Half-Diminished
The C#m7b5add9 chord is built from the notes C# – E – G – B – D#.
Piano sound loads on first tap.
Also known as
C#m9addb5C#m9b5C#min9b5C#mindim9
Chord tones, one by one
C#Root
Root
The fundamental note the chord is built on — C#.
EThird
Minor third
Three semitones — makes the chord minor (darker, sadder).
GFifth
Diminished fifth (♭5)
Six semitones — a flat fifth. Creates instability, typical of m7♭5 and diminished chords.
BSeventh
Minor seventh (♭7)
Ten semitones — the dominant/minor seventh. Adds bluesy tension (7, m7).
D#Extension
Ninth (9)
A 9th — colorful extension a whole step above the octave.
🎼 Related scales
Locrian ♮2 (half-diminished)melodic minor a major 6th below
🎹 Modal analysis
This chord implies the Locrian ♮2 (half-diminished) scale; its characteristic note is the natural 2nd, softer than plain Locrian. It is a mode of the melodic minor a major 6th below.
🎸 Genres
Modern jazz · Post-bop · Fusion