Ab 9
The Ab 9 chord consists of the Ab (Perfect unison), C (Major third), Eb (Perfect fifth), Gb (Minor seventh) and Bb (Major ninth) notes.

How to play the Ab 9 chord
- Find Ab (Root) on the piano keyboard
- Add C (Major third) — 4 semitones above Ab
- Add Eb (Perfect fifth) — 7 semitones above Ab
- Add Gb (Minor seventh) — 10 semitones above Ab
- Add Bb (Major ninth) — 14 semitones above Ab
- Press all 5 notes simultaneously to sound the Ab 9 chord