A-altb9 Minor 7th
The A-altb9 chord is built from the notes A – C – E – G – Bb – B#.
Piano sound loads on first tap.
Chord tones, one by one
ARoot
Root
The fundamental note the chord is built on — A.
CThird
Minor third
Three semitones — makes the chord minor (darker, sadder).
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.
B#Extension
Sharp ninth (♯9)
A ♯9 — the gritty 'Hendrix' tension over a dominant chord.
🎼 Related scales
🎹 Modal analysis
This chord implies the Phrygian scale; its characteristic note is the ♭9 / ♭2.
🎸 Genres
Flamenco · Metal · Modal jazz