F#13(b9) Dominant 7th
The F#13(b9) chord is built from the notes F# – A# – C# – E – G – B – D#.
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Chord tones, one by one
F#Root
Root
The fundamental note the chord is built on — F#.
A#Third
Major third
Four semitones — makes the chord major (brighter, happier).
C#Fifth
Perfect fifth
Seven semitones — the most stable interval, reinforces the root.
ESeventh
Minor seventh (♭7)
Ten semitones — the dominant/minor seventh. Adds bluesy tension (7, m7).
GExtension
Flat ninth (♭9)
A ♭9 — sharp, dissonant tension typical of altered dominant chords.
BExtension
Eleventh (11)
An 11th — a suspended, airy color on top of the chord.
D#Extension
Thirteenth (13)
A 13th — full, rich top extension.
🎼 Related scales
Mixolydian ♭9harmonic major scale
🎹 Modal analysis
This chord implies the Mixolydian ♭9 scale; its characteristic note is the ♭9 / ♭2. It is a mode of the harmonic major scale.
🎸 Genres
Modern jazz · Post-bop · Fusion