By default, the Vintage B3 Organ accepts MIDI input only on MIDI channels 1–3 and ignores MIDI data on channels 4–16. If the track's MIDI channel is set to a value above 3, the Vintage B3 Organ won't respond.
MIDI data on channel 1 or 2 plays the upper or lower Vintage B3 manual. MIDI channel 3 plays the pedal. Set the MIDI channel of the Vintage B3 Organ track to a value between 1 and 3 to play one of the manuals or the pedal.
If you set the MIDI channel parameter to “All,” the MIDI channel of your MIDI keyboard or MIDI notes in regions on the track pass unfiltered to the Vintage B3 Organ. Choose this setting for a split keyboard or a dedicated organ keyboard setup. You can then set a dedicated MIDI mode in the Vintage B3 Organ window. You can change the MIDI channels for either manual and pedal by clicking the Split button in the Main window.
Learn more about the Vintage B3 Organ software instrument