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 StoreAudiobus is the app that makes the rest of your setup better.
Thesys is....now an AB3 midi sender
Yay 
And looks like Effectrix just got an update too.
Comments
The Thesys-fix was long awaitet. Thanks!
Effectrix: The transport-sync doesnt function in audiobus....
Link still broken in Audiobus. No way to start the sequencer. Please fix!