In simple terms, acoustics is the way that sound interacts within physical boundaries. In the case of a home theatre, the boundaries are made up of walls, furnishings, window coverings, and other objects that can either reflect or absorb sound waves at different levels.
As you begin to plan your home theatre you may want to learn the basic concepts that dictate how sound will work in any given environment. This knowledge will equip you to make better decisions related to the design, furnishings, wall coverings, and accessories that you will use to maximize your audio experience.
First Order Reflection
A FOR is the first place a sound wave hits prior to being redirected to your ears. In most rooms this is either a wall, ceiling, floor or object located midway between you and the source of sound. There are two adjustments associated with the tuning of FORs: absorption and diffusion.
Absorption is generally tackled with simple changes, such as fabric coverings and curtains positioned right in front, to the left, or to the right of the speaker, or sometimes on the ceiling and floor. Carpet is a good absorption material, as is a lot of fabric-covered furniture. Hanging rugs on the walls also make a lot of difference. The effect you get is a warmer sound, with less harshness and echo.
The concept of diffusing sound in the home entertainment space is basically aimed at dispersing sound waves in way that best conveys the intent of the original sound and reduces echoes and reflections. Rough surfaces are better dispersers of sound than smooth surfaces. For example, glass, since it is smooth, is a poor diffusing material that results in a faulty listening experience. However, you do need to keep in mind that both absorption and diffusion are needed to achieve the best possible sound. Don’t overdo the rough surfaces, though, as it will result in a muffled sound. Diffusion adjustment, when done right, gives the sound a more spatial quality.
Correcting and Tuning Your Home Theatre
If you are an avid audiophile and you wish to optimize your entertainment environment to get the most out of top-of-the-line electronics, you need to involve an acoustics expert. Of course you could go by trial and error and incorporate furnishings, window coverings, and professional acoustic treatments by simply trusting your own audio instincts, but by doing so you run the risk of a large monetary investment going to waste due to failed results.
Ideally, you want to start thinking about the acoustics of a room at the design stages of your home. If this is not possible, tackling acoustics afterward may require additional tweaking. An alternative to physical acoustic adjustments, and one that is becoming quite popular with audiophiles, is going the digital route. Subwoofers, AV receivers, and AV preamps can adjust the way sound is served without having to make as many changes to the environment. A professional installation of your video and audio equipment, in tandem with good acoustic planning, will always result in a superior entertainment experience.
photo credit: Dusty J