Having listened to a friends set up recently I've realised that my Quake Sub isn't powerfull enough for my 20' x 12' room and I now want harder hitting deeper bass!! Any suggestions on a potential ugrade ?, budget is what ever I get back from the sale of the Rel plus around another £300 - £400. Space is not a big issue so the new sub could be a fair bit bigger than the quake. The Sub is mainly used for movies and is to run with Monitor Audio radius surround speakers. Thanks all, any suggestions gratefully received.