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.
AUM battery drain
It has occured to me now several times that even without using my iPad, its battery was empty from one day to another, with a good remaining charge of 60..80%.
I finally found AUM to be the reason, although it was running in the background and neither MIDI nor audio was running inside AUM.
"Well-behaved" audio apps have an inactivity timer that will put the app in suspended state after an adjustable or fixed time, but I haven't found such a setting either in the app itself or in the iOS settings => AUM.
Apparently AUM will recklessly draw battery until the iDevice switches off, so my question is:
How can I avoid that? Is there a setting that will change this behavior?
Edit: I've found a related thread regarding iOS 13 but I'm on iOS 12.