Bb7(#11) chord for piano presented by keyboard diagrams.
Explanation: The Bb7(#11) alter the Bb7 by the change of one note. The chord name can also be written as Bb7+11 or Bb7#11.
Theory: The Bb7(#11) are identical with the Bb7 except that a sharpenedThe tone is one half step higher eleventh is added (E). Sometimes the fifth (F) is omitted.
Notes: Bb - D - F - Ab - E