Easy do it yourself wall, floor and ceiling system for making acoustical rooms is now available at
http://magnesiacore.com.
A room's acoustics is very important to enjoyability of the A/V experiences.... plus closing the door and turning up the sound level takes your home theatre or music room to higher dimension without disturbing the rest of the house.
You no longer have to build an isolated acoutical room from scratch. Add a tile panel system to walls, floors, ceilings and even on the door of an existing room and they will eat sound on its way out of the room.