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.
Apple Pencil now a MIDI controller
Just discovered this and so haven’t had much time to play with it. But so far it’s pretty damn cool. Sending 4 CCs to LayR, each one sending a different value based on Pencil dynamics (velocity, force, tilt, orientation). You can define which CC control # you want to target for each of the 4 dynamics. Just a heads up, it only works with Apple Pencil.
Pen2Bow by Dimos Gaidatzis
Here is a demo from the developer