Whats the best way to sound proof a std hollow wooden internal door. As i understand it there are 2 kinds of sound damping, the diffusing way to reduce reflections and echoes of acoustics in a room (egg box panels on the walls), but this is not sound proofing but sound damping. I want to be able to sound proof a door to reduce sound coming from one room to another. budget is important, a cost effective solution is sought.