John, if he has an In cabinet sub.. The amp is a separate, the driver and its enclosure is just like a "regular" speaker.. The RCA to the amp, then wire to speaker just like any other speaker..
Amie, it might be worth pointing out that the Subwoofer drivers are Dual voice coil drivers, and require a pair of cables to power both voice coils (especially the inwall subs such as niveka has, maybe this could be brought up at the time of purchase if ordered over the phone)... In the Version 1 of the EP-600's there was only 1 "amp", so Niveka would not have had a problem. But, the new design has an amp for each voice coil. I don't think this is something most people would assume, I think most would assume that there would be one amp channel powering both voice coils in parallel.
Edited by dakkon (08/17/12 11:00 PM)