Audiobus: Use your music apps together.
What is Audiobus? — Audiobus is an award-winning music app for iPhone and iPad which lets you use your other music apps together. Chain effects on your favourite synth, run the output of apps or Audio Units into an app like GarageBand or Loopy, or select a different audio interface output for each app. Route MIDI between apps — drive a synth from a MIDI sequencer, or add an arpeggiator to your MIDI keyboard — or sync with your external MIDI gear. And control your entire setup from a MIDI controller.Download on the App Store
Audiobus is the app that makes the rest of your setup better.
SOLVED (kind of) Will polythemus allow me to play several monophonic mpe synths polyphonically?
Looks interesting, https://apps.apple.com/cn/app/polythemus-au/id1439815017?l=en, but wondering if it would work with shockwave (‘mpe’ monophonic synth).
**Edit: it definitely works to some extent, can do single note pitch bends while playing chords etc. But need to check more to see if full functionality is there **