Arthur Kerns released midiFILTr-VB for Volca Bass. This AUv3 MIDI effect lets you send paraphonic chords to a connected KORG Volca Bass. midiFILTr-VB also exposes some hidden MIDI CCs inside of the Volca Bass.
midiFILTr-VB for Volca Bass App Store Description:midiFILTr-VB is an Audio Unit v3 MIDI Effect and CoreMIDI capable app that allows you to play chords on your Korg Volca Bass synthesizer. Using this app you can make the Volca Bass play with paraphony, meaning when you send it a MIDI chord the Volca Bass will change the pitches of its oscillators to play that chord. There is also a mode where you can set midiFILTr-VB to automatically play a major or minor chord when you send it a single note.
Additionally, the Audio Unit version allows you to control the MIDI CCs of the Volca Bass using AU parameters, including giving you access to the MIDI only parameters of slide, expression and gate length. This makes it easier to map or automate the Volca's MIDI CCs using an AU host.
This app requires:
A hardware Volca Bass
A hardware MIDI interface connected between your iOS device and the Volca Bass
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.