Db maj13/Gb
The Db maj13 chord consists of the Db (Perfect unison), F (Major third), Ab (Perfect fifth), C (Major seventh), Eb (Major ninth) and Bb (Major thirteenth) notes, with Gb as the bass note.

How to play the Db maj13/Gb chord
- Play Gb 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 C (Major seventh) — 11 semitones above Db
- Add Eb (Major ninth) — 14 semitones above Db
- Add Bb (Major thirteenth) — 21 semitones above Db
- Press all 7 notes simultaneously to sound the Db maj13/Gb chord