Hey, i'm a crazy person trying to do harmony effects on a funk tuba. not joking. DonM or other marvelous folks on here, does this thing track if you don't have midi or guitar in? are there controls to force key, or would you bring a little keyboard along to shove notes in key at it to force it to stay in key? Also, any idea of frequency response out of the thing? I play some notes at around 35hz and i'm wondering if it's going to even pick that up, let alone try to put out the 70hz octave above that... Thanks in advance!! -Miles