Hello, Right then, I'm wanting to buy a cheap midi controller to use instead of the GarageBand software keyboard, to input samples. What I am confused about, is how I use it with a presonus firebox that has a midi in/out. It has the normal midi plug plus a breakout cable with rca and a 5 pin din. I have seen a midi controller that is USB powered but I'm not sure if these units are suitable for what I want. In other words can a unit like this be plugged into the firebox midi input and does it also need the usb as well.