FURNISHINGS : Big-Screen TVs Can Be as Good as They Sound

With the introduction of video, a lot of people stopped going to movie theaters and began watching at home. Now, with the advent of large-screen videos, viewers are bringing the theaters right into their homes.

But setting up a home theater involves much more than plopping a big-screen TV in the family room. To get the full effect, the sound has to be as good as the picture, and here is where some thought is needed.

Theater-quality sound is available to the home viewer in the guise of surround sound. This is a system where front, center and rear speaker channels are employed to produce that in-theater feel.

The current issue of Video Magazine offers some suggestions by some leading experts on installing surround sound. Much hinges on selecting the ideal room.

Many people think that a home theater has to be installed in a big room. According to the experts, nothing could be further from the truth.

A large room may not even be desirable, for the simple reason that, as a rule of thumb, the cost of achieving a high level of acoustic performance doubles each time a room’s volume doubles.

The shape of the room is more important than its size. A rectangular room is better than a square one. Square rooms create sound waves that pile on top of each other. Certain spots in a square room will have too much bass, while others will have almost none.

Rectangular proportions spread the sound waves out so they don’t all peak in the same place. Ideally, look for a relationship of 1 to 1.6 to 2.5 among the height, width and length. For example, a room with an 8-foot ceiling implies a width of about 13 feet and a length of 20.

Next, place the speakers correctly. Front speakers should be arranged to the left, right and center of the screen. All front speakers should be at the ear height of the people in the main listening area. The left and right front speakers should be slightly turned in toward the center. The speakers at the sides of the listening area should be at least 2 feet above the seated ear height.

The heart of the system is the decoder, a device that splits the soundtrack and sends it to the various channels. When picking a decoder, make sure that dialogue--the spoken parts of a film--comes from the screen and not from the rear channels. Also, look for a unit with level controls for each channel. These help compensate for badly recorded soundtracks.

Finally, a good surround-sound system doesn’t have to cost more than $1,000. Quality equipment is out there, but consumers have to be willing to look for it. For example, the Onkyo TXSV-50 audio-video receiver can be had for less than $600. Add to that five Boston Acoustics HD5 speakers, which cost about $75 apiece.

For those who are under even tighter budget constraints, Monster Cable makes a set of speakers that come with surround-sound circuitry, eliminating the need for a separate decoder. The speakers cost about $230 a pair.