Can someone clear up how I make this connection please? My Marantz 7200 has a single RCA/phono output for the sub woofer (it is a non-amplified chanel). The sub (Velodyne 8") has *2* RCA/phono inputs (labelled L&R) and a set of regular speaker connections (which I cannot use in this instance) Can I run a co-ax with an RCA/phono on one end (for the amp) to either the left or right channels (not both) OR do I have to split the signal at the speaker. In which case can I just use a Y splitter from Radio Shack? I remember reading somewhere that the volume could be doubled with a splitter. Is that necessary as the sub is powered? Thanks!