How to Soundproof and Improve Acoustics
Consider soundproofing and other ways to improve the acoustics of your home theater if you want to achieve the best possible sound quality with your equipment.
No matter how good your system, if you put it in an environment that is not geared toward good sound quality, even the best audio system will sound bad. The room’s construction, furnishings, and window and wall treatments have a massive effect on the quality of sound from your home theater.
You want to try to control two major types of sound distortions:
Intrusive sounds from outside your home theater
Sound reflections and refractions from the audio system itself
If you’re building a new home or renovating, you have the opportunity to address this at the architectural level. You want to isolate and control the effect of the sound system’s signals on the room itself. The following list gives you some ideas on how best to go about this task:
Place studs appropriately, double your drywall, and insulate for sound. You want to avoid having the studs of two adjacent walls touching each other. By keeping studs from touching, you cut off a primary means for sound to travel between the room and the house (in both directions). You can also dull vibrations by adding a second layer of drywall.
To further dampen any sounds, apply insulation inside the wall cavity. (If this is a concrete basement, consider a vapor barrier as well to keep moisture out of your home theater.)
Apply soundproofing between studs and drywall. Consider adding a layer of soundproofing material between the studs and drywall. This serves not only to suppress sounds going back and forth but also as a vibration trap between the drywall and the studs themselves.
Apply soundproofing to the floor. Think about a floating floor, which is a multilayered floor designed to isolate your home theater from the rest of the house. The topmost floating layer, for example, might consist of tongue-and-groove chipboard bonded to a layer of plasterboard. That in turn would be laid on a spongy layer made of some sort of mineral fiber. You could glue the spongy layer to the existing floor or even mount the whole thing on its own joists.
Apply a soundproofing system to the finished drywall. Adding specialized sound control panels to the walls can help control unwanted reflected sounds. When placed at your speakers' first reflection points (typically, the sidewall boundaries and rear wall behind the main listening position), sound treatment panels reduce your reflected sound. Sound treatments also reduce the overall sound volume in the room, enhancing low-level dialogue and environmental effects delivered over today's high-quality audio systems.
Remember that your cheapest first line of sound defense is simply securing everything that is around the room and listening for things that add noise. Subwoofers can definitely shake things up; if that becomes a problem, get some inexpensive isolation pads for the subwoofer’s feet. Projectors can make a ton of noise, too; consider a special mounting for the projector that contains its noise, but remember not to block the fan and airflow because it puts off a lot of heat, too.