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.
Please post wisdom about AudioLayer here. Discussion of AudioLayer other than knowledge sharing that would go in a wiki belongs in a discussion thread.
A great place to start if you are having trouble figuring out how to import EXS files into AudioLayer is this video from the AudioDabbler:
and this thread (which has a great trick if you are not see the AudioLayer folder in Files on your ipad):
@Lithalean has shared some nice instruments, here:
(Notice that a few of these are sfzs which you will have to convert to EXS)