OTHER TECH

Let's get right to the point: For home theater, a good audio system is just as important as a good video display. Sure, large-screen LCD, plasma, and DLP TVs and video projectors look spectacular. But if you don't have a high-quality audio system to complement the image, you're literally missing out on half of the home-entertainment experience - especially with today's high resolution audio formats like Dolby TrueHD, DTS-HD Master Audio, and the launch of the newly available Dolby Pro Logic IIz. This might be the best investment advice you'll get all year: Don't skimp on the audio system when you buy that big-screen TV!

You don't have to be a rocket scientist to set up a superb-sounding speaker system that'll immerse you in the onscreen action and transport you right onto the bridge of the Enterprise or into the middle of a football game. Also, some of you might already have a high-quality speaker system but feel that you can coax even better performance from it.

In a stereo setup, the left and right speakers should be placed equidistant from the listening position. Ideally, they will also be placed equidistant from the side and rear walls, but not all rooms allow for this. (You don't need a subwoofer for stereo listening as long as the left and right speakers are reasonably full-range.)

Starting With Stereo

While it's great to have multichannel surround sound, it's not mandatory. Many rooms can't accommodate a multichannel speaker setup, and some listeners simply want to stick with stereo. The fact is, even a modest pair of bookshelf speakers can provide a spacious soundstage and a surprising amount of volume and bass. But smaller speakers sound best in a 2.1-channel setup where you have a left and right speaker and a subwoofer. A few stereo receivers have a subwoofer output to accommodate this configuration.

The main difference between a correctly and a haphazardly set up speaker system is that a proper one can immerse listeners in a sense of three dimensional space, while a poorly set up system will seem to have the vocalists and instruments plastered fl at against the speaker grilles.

Before getting into speaker placement, I have to emphasize a crucial fact: The interaction between the speakers and your room is just as important as the room itself. While every speaker has its own sonic voice or "signature," how it actually sounds is inseparable both from the room and from its position in that room. All rooms have areas of bass cancellation, where a speaker's audible output is reduced, and of bass reinforcement, where the same speaker will produce more bass. Cancellation and reinforcement areas can be close together - sometimes moving a speaker a foot or less in any direction can have a major impact on bass performance. The same is true of your listening position - try moving your chair or couch closer to or farther from the front speakers and see if you get an improvement.

Many of the fundamentals of stereo speaker placement also apply to a multichannel speaker setup. First and foremost is the principle of symmetry. Stereo and multichannel speakers won't image properly - that is, they won't place the singers, instruments, and sound effects consistently within the sound field, each contributing to the overall mix from a specific distance and direction - unless they're set up as symmetrically as possible. The left and right speakers should be equidistant from the listening position and the rear walls - and, if possible, from the side walls as well (although this isn't always practical). Don't eyeball this - take out your tape measure, since differences of less than a half inch can be audible, especially with highend speakers and systems.

Stereo speakers, and front left/right speakers in a multichannel setup, should be positioned like mirror images of each other - either facing straight out or angled equally in toward the listening position.

Placing the speakers too far from each other will create a "hole in the middle" effect, while placing them too close together causes stereo imaging to suffer. A good rule of thumb is to divide the wall behind the speakers into thirds and place the speakers at the one-third and two-thirds points, and then move them out an equal distance into the room. Placing the speakers closer to the front wall will increase bass, but possibly at the expense of spaciousness and front-to-back sonic depth. You'll also have to avoid areas of bass cancellation and reinforcement. Experiment with all placement factors including toe-in and even angling the speakers back slightly, until you get to the point where tonal balance, dynamic response, imaging, and sound staging all "lock in" as best as possible. Don't be discouraged if it takes time or more than one listening session. Also, compromises might have to be made to accommodate your room.

While the subject of room acoustics is an article (or a book) in itself, in brief, you need to consider the room's surfaces and furnishings. If one speaker is next to a bare wall and the other is next to heavy drapes, the differences in how those materials reflect and absorb sound waves will cause the two speakers to sound different and make accurate stereo imaging impossible. Consider adjusting the room furnishings if necessary or possible.