The Bb9 sus 4 chord (Bb9 suspended 4, or Ab/Bb) contains the notes Bb, Eb, F, Ab and C. It can be thought of as a Bb9 chord with a 4th (instead of a 3rd) or an Ab chord with a Bb in the bass.

10 Ways To Play The Bb9 Sus 4 chord

If you’ve come to this page just to view some chord diagrams for Bb9 Sus 4 (Ab/Bb), here they are.

Bb9 Sus 4 Chord 10 Shapes