Amaj13b9 Major 7th
The Amaj13b9 chord is built from the notes A – C# – E – G# – Bb – F#.
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Chord tones, one by one
ARoot
Root
The fundamental note the chord is built on — A.
C#Third
Major third
Four semitones — makes the chord major (brighter, happier).
EFifth
Perfect fifth
Seven semitones — the most stable interval, reinforces the root.
G#Seventh
Major seventh
Eleven semitones — a lush, jazzy seventh just below the octave (maj7).
BbExtension
Flat ninth (♭9)
A ♭9 — sharp, dissonant tension typical of altered dominant chords.
F#Extension
Thirteenth (13)
A 13th — full, rich top extension.
🎼 Related scales
🎹 Modal analysis
This chord implies the Lydian ♭2 scale; its characteristic note is the ♭9 / ♭2.
🎸 Genres
Modern jazz · Post-bop · Fusion