Db 7/Bb
The Db 7 chord consists of the Db (Perfect unison), F (Major third), Ab (Perfect fifth) and Cb (Minor seventh) notes, with Bb as the bass note.

How to play the Db 7/Bb chord
- Play Bb as the lowest bass note in the left hand
- Find Db (Root) on the piano keyboard
- Add F (Major third) — 4 semitones above Db
- Add Ab (Perfect fifth) — 7 semitones above Db
- Add Cb (Minor seventh) — 10 semitones above Db
- Press all 5 notes simultaneously to sound the Db 7/Bb chord