Gb add9
The Gb add9 chord consists of the Gb (Perfect unison), Bb (Major third), Db (Perfect fifth) and Ab (Major ninth) notes.

How to play the Gb add9 chord
- Find Gb (Root) on the piano keyboard
- Add Bb (Major third) — 4 semitones above Gb
- Add Db (Perfect fifth) — 7 semitones above Gb
- Add Ab (Major ninth) — 14 semitones above Gb
- Press all 4 notes simultaneously to sound the Gb add9 chord