Ive got 2 sound sources, an emu proteus 2k and a kawai k500s. I also have a pc with cakewalk and a sb live, and a pair of PS6 monitors. Im using the kawais keyboard to control the proteus. Do I need a mixer or is a way that I can have all the sounds coming from the speakers? If I do need a mixer, how is this one; the Behringer euro rack compact.(its about 99 dollars at zzounds, theres one I would also consider for 200)