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.
4Pockets AUM Midi Mixer - Automating on the Timeline Question
If you have several files loaded in all of various lengths and you think ‘right 2 minutes in I want to try a few things - maybe fade in 2&3 and mute 4’. Can you then go to the 2 minute mark on the timeline, draw in the adjustments and play that particular part accurately and listen to it as you make adjustments - or are you just judging where to put in the changes and how they will sound?
So can you listen to any part of the timeline you wish as you make edits?