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.
Xsonic Xtone issues and Censorship on their forums
For anyone using XSONIC Audio products just beware they don't like ANY criticism and they'll ban you form their forums just for stating facts!, they just banned me from showing the tests I made to their "Xtone Pro", so for anyone using their products beware, they have NO customer support and their only person who responds to emails and their forum moderator "Elroy C Hu" will block you immediately!, here are the issues I found with their Xtone Pro:
MIDI switches are useless (and noisy!) as they send MIDI data only while "releasing" the switch and not at the "Press" which makes them useless for any precise control of tap-tempo, loopers, etc.
The continuous control data buffer skips lots of data as it only sends in steps of 8: "0-8-16-24-32.. etc" instead of a smooth 0-127 in steps of 1 value which makes their CC useless for any fine control of volumes, etc. as you'll hear a horrible "skipping, staircase" effect
The phase response of these units is flawed as it creates too much group delay and frequency phase shift where it should have a FLAT phase response, attached here is the result of the Transfer Function made on SMAART, see the inverted polarity of its outputs plus the frequency phase shift
Inverted polarity (negative) on its 1/4 jack outs and headphone outs and positive polarity on its XLR out!, so if you're using both outputs at the same time you'll have cancellations
Too much Roundtrip Latency even at higher sample rates/low buffer, the screenshot here shows almost 12 milliseconds at 96K and 128 buffer
Fixed instrument input with no input level control and fixed limiter and High Pass Filter which heavily affects the dynamics and low frequency response of instruments, (especially low-tuned guitars)
The unit is not reliable at all for live use as it constantly stops sending MIDI messages and you have to unplug it and reboot it
Do NOT buy any XSONIC Audio products! their "Airstep" pedals are also full of bugs!