I'd like to try my hand at a bit of looping, but haven't got the foggiest idea where to start. I'm almost completely clueless about the subject. Essentially, what I'd like to be able to do is to lay down a bass track, loop it, then play guitar over the top of that, looping the guitar as well. A single loop track of bass would probably be enough for my purposes, although I wouldn't rule out using more. I'd definately want to loop multiple tracks of guitar. What would also be nice is if the loops could be triggered by a midi signal, to keep them in synch with drum machines, etc. Is there a single magic box that will let me do all this, or am I looking at getting two units or more?