[cscritter]

After lurking for months and learning a great deal I have a question about upgrading my sub from an old M+K Mx70 to something newer. System is onkyo tx sr805 ,polk rti8s fxi3s and csi3 . Would like to spend around $500. Looking for suggestions and thoughts about the newer subs vs the old mx70, would hate to buy new and find it wasn't really an improvement . Room size 21x14x8 Thanks for any help Chris