Home Theater Acoustics Primer
So you've decided you're going to invest in some home theater equipment. You head off to the dealer's showroom and are blown away by the top of the line system and lay down $5000.00 bucks and head home. Brimming with excitement, you spend hours mounting and installing everything until the big moment when you drop in your favorite DVD only to find that you are missing the smooth and dramatic response you heard at the store. So what's missing?
The bottom line is that once you've reached midrange quality in your AV equipment, the weakest link is going to be the room acoustics, the most overlooked aspect of setting up a home theater. When you are more than a few feet away from the speakers, you are listening from what is called "far field", and the sound is actually coming to you indirectly from the room and not the speakers. Because the speakers are spreading sound in many directions, the room acts like a big filter, exaggerating some sounds while softening others.
Now where do you start? If it is within your budget, it would be well worth the investment to hire a professional acoustical consultant, but if you need to keep your costs down, you can certainly improve your room acoustics by following a few simple rules:
If possible address any excessive outside noise, (HVAC, traffic, footsteps, etc.).
Treat 20% to 40% of your wall space with acoustical absorption panels to reduce reverberation, flutter, and echoes.
Add absorptive bass traps to corners to reduce low frequency build up.
There are many noise control products to keep unwanted sounds from entering your home theater. Duct Silencers and pipe and duct lagging to reduce HVAC noise, vinyl noise barrier and isolation clips to decouple walls and ceilings thus interrupting the transmission of sound waves, as well as acoustic doors and door seal kits. The goal here is to improve speech intelligibility in the movie's soundtrack by lowering the signal to noise ratio (that is, the relative strength of the speech vs. the background noise).
Acoustic panels and bass traps come in a wide variety of materials and price ranges. There are custom fabric wrapped panels that can be made to seamlessly integrate with the room's décor, as well as out of the box kits. The main thing to remember is that a mediocre sound system in a well-tuned room will outperform a top of the line sound system in a poorly tuned room.