Bb Minor 6th (Bbm6)
Also written as A# Minor 6th (A# and Bb are the same key).
Notes in Bb Minor 6th
Inversions
Same notes as Bb Minor 6th, with a different chord tone as the lowest note. Useful for smoother movement between chords instead of jumping around the keyboard.
Root position
A# in the bass
1st inversion
C# in the bass (Bbm6/C#)
2nd inversion
E# in the bass (Bbm6/E#)
3rd inversion
G in the bass (Bbm6/G)
Open voicings
A close-position chord like Bb Minor 6th can sound cluttered in the middle of the keyboard. Jazz players open it up by dropping one note down an octave, spreading the same notes wider without changing the chord.
Drop 2
E# on the bottom
Drop 3
C# on the bottom
Bb Minor 6th is built from A#, C#, E# and G.
A minor triad with a major sixth on top carries a bittersweet color a plain minor chord doesn't have. Composers reach for it when a minor chord needs an extra touch of melancholy without sliding into the more overtly jazzy sound of a minor seventh.