Tune the PRO FORMANCE

1. Locate the Fine Tune Control.
2. Set the control to the center detent position for Concert Pitch (A=440 Hz).
3. Turn clockwise to raise pitch (up to ± 1/2 semitone).
4. Turn counter-clockwise to lower pitch (up to ± 1/2 semitone).

Source: PROformance Plus — emu-proformance-om (manual)