My SVS PB2 plus should be ariving soon and I'm a little worried about controlling the beast as my HT room is upstairs and is suseptable to vibrations. When I originaly fitted the room out I decided I wanted to try and reinforce the floor as well as try and sound proof it to a certain extent. The original floor is made up of what looked like some type of chipboard paneling so on top of this I laid acoustic/thermal insulation tiles and on top of this I screwed down boards of gyproc soundbloc boarding. On top of this I laid black carpet. I then covered concrete slabs with offcuts from the same carpet and positioned my speakers on top of these. As a whole it seams to work really well short of having the floor concreted. But I am affraid the PB2 plus will be harder to control than my little REL StrataIII, so I have already constructed a super heavy duty isolation platform for the PB2 plus. This consists of a base layer of 18mm MDF, glued on top of this is a foam acoustic isolation tile and on top of that two concrete slabs. This is all wrapped up in the same carpet as my AV room floor and looks really neat despite its size. Does anyone else have any suggestions with regard to isolation and positioning to get the best most accurate performance out of a big sub?