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.
The piano and bass on this one are from the Kawai MP11se. The piano is a sampled Shigeru grand and quite good (maybe better than my iOS favs). The upright bass also excellent. I added SWAM Tenor Sax and Euphonium and SoftDrummer. I have the Shigeru patch on my current Kawai ES8. The problem using it is it requires an interface to record midi and audio, so one cannot edit the original Shigeru sound, just the blank midi.
Fortunately, this piano improv required no edits.