midiFILTr-VF is an AudioBus 3 MIDI filter effect and CoreMIDI capable app that improves the MIDI capabilities of a hardware Volca FM synthesizer. The Volca FM is notorious for having a unique MIDI spec that does not listen to the velocity of incoming MIDI notes. midiFILTr-VF allows you to play notes with velocity as you would expect to by adding a MIDI CC message along with each note that controls the note's velocity.
This app requires:
A hardware Volca FM synthesizer
A hardware MIDI interface connected to the Volca FM
The AudioBus 3 app is recommended for ease of use, though the app can also be configured with regular CoreMIDI.