I've decided to set up half of my basement as my HT area, but the sound from the basement can be heard anywhere in the house. I think the reason for this is that the hardwood floor on the first level and the basement ceiling are the exact same boards, so there's no buffer for sound. The basement ceiling is basically the boards plus support beams. So what would be a good, cheap way to soundproof the ceiling? The layout is just an 11'x17' rectangle, and rafters(?) run across the width.