:: Source Components

Source Components are any products that retrieve information from a storage medium or pick up a broadcast signal. A VHS tape machine is a source component because it reads the audio and video signals on a tape and presents them to the rest of the home-theater system. Other audio /video source components include DVD players, HDTV set-top boxes, or Digital Satellite System (DSS).

:: Home Theater Controllers, Power Amplifiers, and Receivers

The job of separating (decoding) the 2-channel Dolby Surround or discrete Dolby Digital signal into multi-channel surround sound is of the audio/video controller, also called an audio/video preamplifier . In addition to performing surround-sound decoding, the controller is also the Grand Central Station of the entertainment system. It receives audio and video signals from the source components (VHS, DSS, set-top boxes, DVD) and selects which one is decoded and amplified by home- theater audio system and sent to video monitor.

New surround sound formats can deliver more than 5.1 channels of audio information. These formats, called THX Surround EX and DTS-ES have an additional channel (called "back-surround") that drives additional round speaker or speakers located directly behind the listening position. Controllers that support THX Surround EX and DTS-ES have eight line-level outputs rather than six.

These six or eight separate outputs arc fed to a 5- or 7-channel power amplifier (plus an optional subwoofer), where they are amplified to a level sufficient to drive the home theater's loudspeaker system. A home-theater power amplifier can have five, six, or six amplifier channels in a single chassis.