The Velodyne HGS 15 and 18 have line level and speaker level inputs and outputs. They also have XLR inputs. There is volume control on the remote, so you have bass management no matter what the source is. They have tremendous power and very low distortion. I heard a couple of subs from Sunfire, Mirage, Rel, and some others, I bought the HGS 15.
Sonny
Sonny