Hi all, My friend currently owns an Onkyo 600 receiver and is currently looking to buy mains/rears. However, in the interim, he wants to hook his computer speaker system (i.e. Receiver ---> Subwoofer ----> 4 Speakers). The Sub only has an RCA out and no other inputs/outputs. What is the proper connection to the receiver for this Sub? Im assuming it's not supposed to be connected to the subout but rather as a L/R input. Still it's not been working.