Bbaug7 chord for piano with keyboard diagram.
Explanation: The Bbaug7 is a four-note chord. Bbaug7 can also be written as Bb+7, Bb7+ or Bb7#5. Notice that Bbaug7 are identical with Bb7+5.
Theory: The Bbaug7 is an augmented chord extended with a minor seventh.
Notes: Bb - D - F# - Ab