After looking at Polks PSW404 manual, it has no mention of hooking up the sub with a y adapter. But I just received my sub cable and it came along with a y-adapter. I was wondering if I should hook up my sub with the y adapter or leave it to just the L filtered line input. It sounds all right so far, but I was wondering if I went along and connected the y adapter if I would harm to sub or not. BTW, Im using a Denon 1803 reciever (has just a Sub Out) Also what it the difference between the R & L filtered input and the LFE unfiltered?