Why not use _____ ?

Limitations are good. It doesn’t really restrict creativity: limitations focus it.

The current idea is that whatever equipment I use has to fit in a single backpack. That doesn’t mean I only use iPads since I can see working in some traditional instruments at some point. I might change my keyboard controller in the near future if I find one that does what I want, but it has to either run off of batteries or the tablet’s battery—I want the core bit of my setup to not require plugging into a power socket.