Fb11 chord
The F-flat dominant eleventh chord (abbreviated "Fb11 chord") is a six-note chord consisting of the notes F♭, A♭, C♭, E♭♭, G♭, and B♭♭. The chord is formed by adding an eleventh to a F-flat dominant ninth chord.
In practice, the third (A♭) and fifth (C♭) are often omitted from the Fb11 chord to avoid a very dissonant sound, and because it's not always possible to play all notes simultaneously.
Name
F-flat dominant eleventh chord
Notes
F♭ A♭ C♭ E♭♭ G♭ B♭♭
Intervals
1 3 5 ♭7 9 11
Chord symbol
F♭11
Type
Hexad (six-note chord)