A Surround-Sound Primer

You know the drill: You have your popcorn ready, and you're ready to plop onto the couch and watch a movie on your home theater system. So you put in a DVD and click through to find the setup screen, where several surround-sound options are available. But which setting should you select?

Before you choose, you should know how to select a surround mode suitable for your home theater equipment, and to do that you should understand how the formats work. To help you make sense of surround-sound terminology, we've defined all of the major surround-sound encoding and decoding formats in the following pages.

Surround-sound encoding repackages multiple audio channels in a format that is more convenient for storage or transmission, while decoding reverses the process to play the signal. The audio is encoded at its source--when a DVD is produced, for example. It gets decoded by whatever you use to play it--in the case of a DVD movie, your DVD player or your A/V (audio/video) receiver. The decoding applied to a signal must match the encoding scheme that was used to create it, or else you may wind up with no sound at all.

DVD movies and HDTV programs use special techniques to encode and store soundtracks containing more than two channels of audio. An A/V receiver, which sits at the heart of most home theater systems, handles the signal routing from the DVD player, VCR, or TV; the amplification to the loudspeakers; and, critically, the surround decoding. A digital connection between components is generally preferable, and is the alternative that will be assumed henceforward.

Remember that choosing the correct decoding option will yield the best sound quality when you sit down to enjoy a movie. If you'd like to know more about setting up your own surround-sound home theater system, see "Recycle Your Stereo for Surround Sound."