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.
AudioBus multiroute to internal speakers plus USB?
Is it possible to have AudioBus' Multiroute Audio setting apply to the built-in speakers?
Use case: OP-Z plugged into 2018 iPad Pro. The OP-Z is a 2x2 USB audio interface, but I can't monitor the iPad's audio when it's connected this way.
If I could also route audio to the speakers, as well as the USB port, this would solve the problem.