Just to add my .02, I purchased dual Klipsch subs and after trying to integrate and adjust them properly sent them back after just 3 days. They were some of the worst sounding subs I've bought. I preferred the old Definitive Tech sub I had at the time over them. I ended up trying out a Velodyne which sounded great but was not enough to fill my room. Currently have a Rythmik FV15HP which has opened my eyes to good quality sub sound and output.