Ok I've done my searching and reading from previous posts, I still didn't get an answer to my little problem. I've got a 7cu.ft enclosure with a 13" JL Audio W7 series Subwoofer tuned to 18hz which weighs approximately 80kgs. It is a 5ft tall tower, hence I need it to balance properly. The enclosure is slot ported, with approximately 60square inches of port area and the port is downfiring with the subwoofer side firing. The enclosure sits behind a sofa, in a corner right now. With only 250wrms going to it, the whole house literally shakes apart, and this thing needs at least 1000wrms to reach it's full potential, so before I do actually put the power on it I want to decouple the subwoofer from the wooden, carpet covered floor. As it is right now the subwoofer does tend to get a bit boomy and is not related directly to the subwoofer itself or the enclosure, and as far as I can tell is due to the subwoofer being coupled to the floor. The enclosure is built like a tank, with it being braced in every possible way. My question is... How would I go about decoupling a monster this heavy? I was thinking multiple half squash balls with silicone on the inside, but then the whole thing would be sitting on balls, hence I'm a bit suspicious that it would be unstable. I've heard of Marble and/or Concrete slabs being used but not heard of any positive results. Anybody have any suggestions? Thanks, Mitul.