When soundproofing a room installing the proper door is one of the most important elements. Allot of the sound leakage from the room will be through the door. Standard interior doors provide nearly no sound isolation. You must use a solid exterior type door. Best is a solid 2″ MDF type with a metal shell.

For the best sound isolation the best method is to use two doors with an air gap in between. The dead air between the doors acts as a sound barrier. This air gap can be as little as a few inches or if you have the space it is best to have a sound lock or a small room or hallway between the two doors.

The seal around the doors is also very important. The frame around the door must seal completely. Again the best is a metal frame and one that is design to fit the door.

The door sweep is another important element. You need to install a piece of rubber molding at the the bottom of the door so that it rubs on the floor and there is no air gap.