Configure MIDI Overflow Mode (32 Note Polyphony)

1. Connect the MIDI Out of the first PRO FORMANCE to the MIDI In of a second PRO FORMANCE.
2. Connect the audio outputs of both units to your mixer/amplifier.
3. Ensure both units are configured to the same MIDI Channel or Omni mode.
4. If using the PRO FORMANCE +, you must select the split point on both units individually if using split presets.

The first unit will automatically enter Overflow mode and route excess notes to the second unit.

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