Gb add13/D
The Gb add13 chord consists of the Gb (Perfect unison), Bb (Major third), Db (Perfect fifth) and Eb (Major thirteenth) notes, with D as the bass note.

How to play the Gb add13/D chord
- Play D as the lowest bass note in the left hand
- Find Gb (Root) on the piano keyboard
- Add Bb (Major third) — 4 semitones above Gb
- Add Db (Perfect fifth) — 7 semitones above Gb
- Add Eb (Major thirteenth) — 21 semitones above Gb
- Press all 5 notes simultaneously to sound the Gb add13/D chord