Caustic is also a great app to make music upon, though in the Android (and iOS, maybe) versions, you need to have an unlocking key installed to unleash all the remaining features. Moving on to the next, this DAW-in-an-app is good for live gigs, and if you want to experiment with natural and unconventional sounds without the hassle of having to install external plugins, as everything you need in music production, from vocoder to modular synthesizer to supersaws, are all self-contained.