By far one of my favorite iPhone apps, SynthPond provides a blank canvas for sound experimentation, accessed using cell/planet-esque components with individual parameters set by the user or at random. SynthPond’s creator ZachGage writes –

synthPond is a music / art piece that I made for the iphone. It’s a spatial synthesizer, and it’s in the vein of toshio iwai’s stuff… theres a free lite version that i think is pretty full featured, and there’s upcoming OSC support that will work with any osc device.

The 3D audio output from the app is quite interesting, very often soothing. I still find myself experimenting with groups of orbitting ‘reactors’ which can be surprisingly fun. – SynthPond