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.
25 FREE Music Making Apps for iOS | NO IAP - haQ attaQ
Here are 25 completely FREE music making apps for iOS. No freemium apps, no IAP's and No strings attached. There are a lot of free apps on the Appstore and I've gone through over 500 music apps, for both iPad and iPhone, just to find the most useful ones. I've managed to find Synthesizers, Drummachines, Delays, Flangers, MIDI tools and a few other goodies. However, the list isn't perfect because I was working under a strict set of rules ...