I have recently experimented with bringing my sub from a dedicated home threater into my two channel system (consisting of paradigm signature 2's). I immediately loved the additional bottom end as the sub really filled out the presentation and created a much more enveloping sound. However, I still don't feel that I've got the placement, crossover, and phase perfect. Honestly i don't know if I ever will. Rather that spending the bucks on a sub more suited to music and my monitors(was thinking about the paradigm sub 1 but that a big chunk of change) and trying to get it perfectly integrated, I'm now just going to upgrade to a floorstanding speaker that can play close to full range.
SB
SB