sorry for such a basic question--but I am new to this. I am getting a home theater set up and am considering these speakers as my towers. My room is about 20 by 20 with open walls on 2 sides to rest of house. Are these good speakers for the price? I have a Yamaha SW150 double 8 inch subwoofer--do you think this sub will be sufficient with these speakers or should I go with a 10 inch sub? Thanks!