Right now I am using one Sunfire True subwoofer. Its 13 inches cubed in size. The room I have it in is pretty big and opens to several other rooms. I want more bass. I don't really have the floor space for anything much bigger than the Sunfire. What should I do to get more bass? I've already upgraded my mains to RTi150s and added a external amp for more bass from the mains. I suppose I could add a SVS tower sub, but damn those things are ugly. Are there any other subs about the same size as the Sunfire that will have more output? I'm considering saving up for a JL sub that would fit the floorspace, but the cheaper option would probably be to add a similar Sunfire on the other side of the entertainment center.
Any thoughts? Anything I am missing or passing over?