I'm using 18 ga Radio Shack wire in mine, and there is a little more room, so I would guess that 16ga would work. You could always use bannana plugs at the speakers, and they sell some things at Best Buy (saw them yesterday) that screw onto the ends of cables and adapt down to a smaller gold wire that would go into the sub ($$$). Personally, I would say that 16ga Monster Cable is overkill unless your speakers are really far apart. For what it's worth, I could not tell a difference in sound quality when I changed the cable, I just needed longer wires.