The subwoofer has it's own power amp and you can connect this to the Onkyo receiver. The connection on the back of the Yamaha to look for is the input, the others are for connecting other speaker to cover the higher frequency. There should also be a volume control on the back of the subwoofer along with frequency cutoff. Depending of the other speakers you have connected and the range of frequency the cover, normally this should be set at 80HZ. Hope this will help you out.
