If you are ever going to add a/multiple sub woofers with k-horns,I hear the rule is to never go with a smaller woofer size in the sub,as in the main speakers. I recommend going with a really nice klipsch dual 12' sub,or that very powerful 15' with the 15' radiator sub klipsch only produced in 2002 I believe. That sub has a rating of 2800 watts I believe..?? It has been a while since I owned one,but let me tell you that this sub is the baddest home stereo powered sub I have ever heard! I had just the one sub,(it had a 15' copper colored sub on each end,and I was powering a set of lascalla's with a adcom gfa 555,and a pair of cornwall 1's upgraded with bob crites everything,with the old adcom 565 mono blocks,and 565 adcom pre amp,that had the see through cover. That was my favorite system,and without that sub,it was like night and day!!