Whether you are building a recording studio, home theater or simply want to stop noise from escaping a room, you have to start with the understanding that there is a difference between controlling sound within a room versus stopping sound from exiting the room.

For instance, you would control sound within the room by placing panels on the walls to reduce echo so that the sound inside the room is better. To stop sound, you have to start by stopping air from escaping. In studios, this is done by introducing specially designed windows and doors into the equation. Both of these follow a similar approach to building an offset stud wall whereby the inside surface of the wall is disconnected from the outside surface. These walls work best when they are heavy and if at all possible, have wall surfaces of differing mass.

Studio doors and windows follow the same rule of thumb. A great place to find good heavy doors is at the used building supply yard. Schools and other pubic buildings are always upgrading their doors to meet ever more stringent fire codes. This forces them to abandon solid core wood doors which are often perfectly suited for sound isolation use. Two doors are generally used with each one opening into their own room and creating an air space between them. Good exterior door insulation is then added all away around the door… and don’t forger the floor! Where air passes so does sound.

Windows tend to be a bit more complicated to construct as you will likely have to create a window frame to separate the two (or three!) panels of glass. Again, your used building supply shop may have some good heavy glass that can be used. If at all possible, try to use say ¼” glass for one pane and maybe 5/16” glass for the other. The heavier the better and they should be of different mass. This will reduce the chance of the tow pieces of glass vibrating sympathetically.

When mounting the glass in the frame, you want to have it sit on a rubber surround so that it floats. This will help eliminate any rattling that could occur when bass is tuned up on your sound system. If you like, try angling one of the glass panes so that the air space in between the two pieces graduates. This will further improve the performance by eliminating standing waves inside the glass from forming.