B9#11 Dominant 7th
The B9#11 chord is built from the notes B – D# – F# – A – C# – E#.
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Also known as
B#11B9(#11)B9(#4)
Chord tones, one by one
BRoot
Root
The fundamental note the chord is built on — B.
D#Third
Major third
Four semitones — makes the chord major (brighter, happier).
F#Fifth
Perfect fifth
Seven semitones — the most stable interval, reinforces the root.
ASeventh
Minor seventh (♭7)
Ten semitones — the dominant/minor seventh. Adds bluesy tension (7, m7).
C#Extension
Ninth (9)
A 9th — colorful extension a whole step above the octave.
E#Extension
Sharp eleventh (♯11)
A ♯11 — the bright, floating Lydian color.
🎼 Related scales
Lydian dominant (acoustic)melodic minor a perfect 4th below
🎹 Modal analysis
This chord implies the Lydian dominant (acoustic) scale; its characteristic note is the ♯11 over a ♭7 (the acoustic sound). It is a mode of the melodic minor a perfect 4th below.
🎸 Genres
Jazz fusion · Modal jazz · Bossa/MPB