midiFILTr-VS is an Audio Unit v3 MIDI Effect and CoreMIDI capable app that improves the MIDI capabilities of a hardware Volca Sampler. The Volca Sampler is notorious for having a unique MIDI spec that requires you to trigger individual parts on different MIDI channels. midiFILTr-VS allows you to trigger parts as you would normally expect to trigger a sampler.

midiFILTr-VS has three modes:
OCTAVE mode - C notes on any octave always trigger Volca part 1, C# triggers part 2, D triggers part 3, etc.
DRUM mode - The general MIDI drum spec is used to trigger the individual parts. Bass Drum triggers part 1, Snare part 2, Closed Hat part 9, etc.
PITCH mode - The Volca works normally triggering its 10 parts on 10 different MIDI channels. But instead of the Volca default of always playing that sample at the same pitch, the incoming note value will effect that sample's pitch.

The AUv3 also allows you to map note velocity to part volume, and provides AU parameters that map to the Volca’s MIDI CCs for easy control from your AU host

This app requires:
A hardware Volca Sampler
A hardware MIDI interface connected to the Sampler

An Audio Unit host that supports AUv3 MIDI Effects such as AudioBus or AUM is recommended for ease of use, though the app can also be configured with regular CoreMIDI.