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 feature request: show currently active destinations in MIDI receiver dialog
Sometimes I add an audio source first in the Audio screen, and later on I decide to add MIDI control to it in the MIDI screen. To do that, I have to scroll through my list of AUs, find the same plugin and select "Instance A".
@Michael could you add some way of quickly selecting the MIDI destinations I already have active as audio sources? Now that I think of it, it could also work by long pressing the audio source itself or something like that.