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.
OT: MSoundFactory beta over 70% off (with code)
For those with desktop systems, this newly released sound design package is very deep, and steeply discounted for a limited time. New customers can get an additional 20% off with code MELDA2608397.
I've been playing with it for the past few days and I'm very impressed with the interface and the multitude of plugins and options available.