I never could get subs to match up right with any speakers including the one pi s. They always sound like two different sound makers and only mixed when I was at a distance. I have not tried the four pi s yet. This includes in autos also. The speakers by themself always sounded better and I do like a good bass punch with the capability of still hearing a pluck of a bass fiddle. Ok my first stab at a four pi was that you could hear the bass fiddle but not enough punch. That's without a sub, with 4 db of 100 hz bass added plus the loudness control on. Any suggestions? Thanks and hey is there a 10 db bump at the Rz freq. of the woofer using a tube amp with a output transformer?