There really is no such thing as a "subwoofer" cable. They just market them that way. Any RCA type connector running from the sub out to line in will work just fine.

The receivers have many settings on them that need to be set to correctly represent your system. Although most don't like it, one of the best things you can do is read and re-read your owners manuals and apply what you learn to your system. It took me numerous reads of my receiver manual to figure out what each setting meant and what it did.

Don't overlook the subwoofer manual as well.