Bb11 chord
The B-flat dominant eleventh chord (abbreviated "Bb11 chord") is a six-note chord consisting of the notes B♭, D, F, A♭, C, and E♭. The chord is formed by adding an eleventh to a B-flat dominant ninth chord.
In practice, the third (D) and fifth (F) are often omitted from the Bb11 chord to avoid a very dissonant sound, and because it's not always possible to play all notes simultaneously.
Name
B-flat dominant eleventh chord
Notes
B♭ D F A♭ C E♭
Intervals
1 3 5 ♭7 9 11
Chord symbol
B♭11
Type
hexad (six-note chord)