THE HOME THEATER IS AN IMPORTANT PART OF WHAT MAKES A DIGITAL HOME unique. And when designing a home theater, there are many systems and components the builder and integrator can install. But a good end result is a team effort. Well designed equipment is part of it. Providing the right acoustical setting is the rest.

For the most part, loudspeakers themselves determine what we hear at middle and high frequencies—voices, and most music. This is great news, because it means that truly good loudspeakers can sound great in most normally furnished rooms.

However, what happens at low frequencies is very different—and bass is very important to the home buyer's listening pleasure. All rooms create resonances, and the standing waves that result from sounds reflecting back and forth between and among walls, floor, and ceiling change what people hear. The frequencies and problem locations within a room depend on the room's dimensions, where loudspeakers are located, and where listeners might sit. Because all rooms are different, universal solutions are impossible. But there are solutions.

As builders, architects, and installers design and construct a home theater or media room, keep in mind the effect of standing waves. The old notion that there are “ideal” room dimensions, or ratios of dimensions, is a fantasy, based on conditions that do not exist in real-life rooms and audio systems. However, it is good practice to avoid square rooms, long narrow rooms, or room dimensions that are simple multiples of one another. Even for these rooms, though, there are solutions, involving large amounts of low-frequency sound absorption, or multiple subwoofers to attenuate the standing waves (see “Subwoofers: How Many and Where?” page 20).

There is little the equipment manufacturer, or even the builder, can do to guarantee good bass. But a combination of technology and acoustical knowledge can help deliver great listening experiences. This is where trained installers and acoustical consultants get involved (builders and architects can find experts through the Custom Electronic Design and Installation Association at www.cedia.net).

Speaker Placement Key

Assuming the home buyer has selected well designed speakers, there are simple guidelines for placing them to achieve optimal surround sound.

When builder and installer meet with home buyers, they should use all of their powers of persuasion to convince the customer that proper sound is an important part of a home theater experience and they should plan carefully where they want their sound to come from.

Traditional freestanding loudspeakers are getting serious competition from in-wall and in-ceiling loudspeakers. Not everyone, it seems, wants their room cluttered with boxes and towers. Fortunately, the best in-wall speakers compete favorably with traditional loudspeakers in sound quality, and they are less visually obtrusive. But proceed with caution.

For example, ceiling locations are simply not ideal for theater speakers. This is especially true of front speakers, for two reasons. First, sound is perceived as coming from the ceiling location, far from where the lips are moving on the screen. The larger the distance between picture and speakers, the worse the problem.

Second, the homeowner now has the best sound aimed at the floor. Tilting the tweeter can help with high frequencies, but overall sound quality will still be inferior when compared to good forward-firing, in-wall speakers.