Is it a bad idea to hook up a passive sub-woofer and a powered sub to the same system? I hooked up a Sony SA-WM40 along with my passive Kenwood Sub. The sony is hooked up through the receivers pre-out and my front home theater speakers are running through the kenwood (they are small 4" main 1" tweeter"). It sounds pretty good, but am I just kidding myself. Is it a better idea to just scrap the Kenwood and go with just the Sony?