In this demo FieldScaper uses one oscillator (from three) in loop mode for processing external sound from Polivoks synth. Three default presets were used within this demo.
Two presets configure FieldScaper osc for processing sound directly as it comes from the input. And one preset slices the sound of input loop on small pieces and plays them in random sequences. Which creates the new and very different from source sound.
[ More about FieldScaper app ]
iPad can give not bad quality of sound even with internal AD/DA for live performance with processing external sound sources like a synth. Very low cost and lightweight solution.
Here is DIY 4-pole headphone jack adapter (you can make it even smaller) and its diagram:
[ More about this Polivoks synth mod ]