What Zman is describing is the way I have my sub hooked up. A second set of speaker cables is hooked to the same speaker terminals as the main speakers. It sounds all wrong, but the input impedance through the sub's speaker (high level) inputs is high enough that it isn't a problem. Then, as Lewhite says, set a low frequency on the sub's crossover.
using Velodyne sub in 2-channel setup?
I want to use pure diect mode on Marantz receiver because sound quality is better than stereo. If I run L/R preouts to sub in, then sub out to power amp to speakers using sub x-over, will I lose signal stregth or sound quality? Should my better interconnects be used in front of sub or in front of amp? I was thinking amp.