I was wonderting if anyone here stacks subwoofers. I will have 2 subs soon and they will both be sealed. One is a 1.2cf box and the other will be a 2.2cf box both with 12'' drivers a Shiva X and the other is an ED 13.0v2. Is there any reason not to do this and if so why? Also if you do stack them should they be attached to eachother or is it better to have a little isolation between them. My room is not very big so space is at a premium........Any advice?