- Press the [MASTER] button.
- Select the 'MIDI MODE' screen.
- Set the mode to 'MULTI'.
- (Optional) Navigate to 'MIDI ENABLE' to turn specific channels On or Off.
Source: Proteus FX — proteusfxownersmanual (manual)
Symptoms this guide addresses
Source: Proteus FX — proteusfxownersmanual (manual)