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.
How I sample internally using IOS
Say for example you have an app that makes interesting sounds but isn’t Audiobus or auv3....
First go to settings
Select customize controls
Add screen recording
Open app you want to sample
Swipe up from bottom of screen and click the screen recording button
After the 3 second countdown recording will begin
After recording you will have a video file in your photos with the audio!
Download a free app called mymp3 player and open the file from your photos
Convert to mp3 and send to twisted wave to chop and convert to wav
I have used this technique to sample YouTube videos and apps I want to sample