E addb9/A#
The E addb9 chord consists of the E (Perfect unison), G# (Major third), B (Perfect fifth) and F (Minor ninth) notes, with A# as the bass note.

How to play the E addb9/A# chord
- Play A# as the lowest bass note in the left hand
- Find E (Root) on the piano keyboard
- Add G# (Major third) — 4 semitones above E
- Add B (Perfect fifth) — 7 semitones above E
- Add F (Minor ninth) — 13 semitones above E
- Press all 5 notes simultaneously to sound the E addb9/A# chord