C#ma7#9 Major 7th
The C#ma7#9 chord is built from the notes C# – E# – G# – B# – D##.
Piano sound loads on first tap.
Also known as
C#ma7add#9C#maj#9C#maj7add#9
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).
G#Fifth
Perfect fifth
Seven semitones — the most stable interval, reinforces the root.
B#Seventh
Major seventh
Eleven semitones — a lush, jazzy seventh just below the octave (maj7).
D##Extension
Sharp ninth (♯9)
A ♯9 — the gritty 'Hendrix' tension over a dominant chord.
🎼 Related scales
Lydian ♯2harmonic minor a major 3rd below
🎹 Modal analysis
This chord implies the Lydian ♯2 scale; its characteristic note is the ♯2 / ♯9 (augmented 2nd). It is a mode of the harmonic minor a major 3rd below.
🎸 Genres
Gypsy jazz · Roma music · Klezmer · Classical