Quality over Quantity. REL T/7x. I have one in my room and it integrates seamlessly with my monitors. I see no reason why I would need 2. My room is about the size of yours and the T/7x pressurizes it just fine. Bass slams you in the guts and sometimes vibrates the whole couch. Queen Mary by Francine Thirteen will make your whole body vibrate (powerful low 30s Hz).
