F# addb9
The F# addb9 chord consists of the F# (Perfect unison), A# (Major third), C# (Perfect fifth) and G (Minor ninth) notes.

How to play the F# addb9 chord
- Find F# (Root) on the piano keyboard
- Add A# (Major third) — 4 semitones above F#
- Add C# (Perfect fifth) — 7 semitones above F#
- Add G (Minor ninth) — 13 semitones above F#
- Press all 4 notes simultaneously to sound the F# addb9 chord