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.
Behringer UMC 1820 works great with iPad mini 4
I setup my new Behringer UMC 1820 with the iPad mini 4 last night. I got it to replace the Roland UA-22 + USB Streamer combo that I was using with my Expert Sleepers ES-3/ES-6. Since both the UA-22 and USB Streamer are audio interfaces, I couldn't use them both at the same time. The UMC 1820 is like having both the UA-22 and USB Streamer combined with many more inputs/outputs. With all these channels I can use AUM to apply different effects to each of my hardware synths plus have the ES-3/ES-6 for sending/receiving DC-coupled CV (or audio) to and from my Eurorack modular using the ADAT connections. The only issue I had setting it up was that I didn't realize it doesn't override the iPad's audio so I wasn't getting any sound from the unit until I cranked up the iPad volume. This was a bit strange, since all the other audio interfaces I've used disable the iPad's volume buttons.