A(b9#11) Dominant 7th
The A(b9#11) chord is built from the notes A – C# – E – G – Bb – D#.
Piano sound loads on first tap.
Also known as
A7#11b9A7b9#11
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.
GSeventh
Minor seventh (♭7)
Ten semitones — the dominant/minor seventh. Adds bluesy tension (7, m7).
BbExtension
Flat ninth (♭9)
A ♭9 — sharp, dissonant tension typical of altered dominant chords.
D#Extension
Sharp eleventh (♯11)
A ♯11 — the bright, floating Lydian color.
🎼 Related scales
🎹 Modal analysis
This chord implies the Half-whole diminished scale; its characteristic note is the ♭9 / ♭2.
🎸 Genres
Bebop jazz · Hard bop · Gypsy jazz