Polivoks synth with FieldScaper app. Demo of original sound and processed by FieldScaper with several default presets. Synth connected to iPad through 4-pole headphone jack adapter. No external power, no any extra audio interfaces. Only small adapter (white box on video with input level knob).
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.
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: