Bb7+9 (Bb7#9) altered chord
Altered Bb chord for piano presented by keyboard diagrams.
Explanation: The Bb7+9 alter the B#9 by the change of one note. The chord name can also be written as Bb7#9 or Bb7(#9).
Theory: The Bb7+9 are identical with the Bb9 except that the major ninth is sharpenedThe tone is one half step higher.
Notes: Bb - D - F - Ab - C#