What Is a Digital Theater System?

Digital theater systems contain multiple components.

In home theater systems, the term "digital" refers to the way sound and images are produced. Older analog-based systems used signals that were analogous to the source signal (hence the name). Digital systems, on the other hand, convert the signals to digital codes -- basically a series of 1s and 0s--that use much less space than an analog system and can thus carry much more information. Digital theater systems take advantage of that.

The Screen

The screen of a digital theater system should be high definition to ensure that it makes the most of digital technology. Since digital signals carry more information, they can create a clearer and more detailed image. A screen's definition is measured by the number of horizontal pixel lines it carries, as well as whether it is progressive (uses all the lines at once) or interlaced (flickers back and forth between one half of the lines and the other faster than the human eye can perceive.) So a 1080p resolution means 1080 horizontal lines delivered progressively while 720i means 720 horizontal lines delivered interlaced. The higher the number, the more information the TV can receive through digital signals and the more detailed the image.

Sound

Digital theater systems use multi-channeled sound to deliver a very realistic audio presentation. Most are either 5.1 or 7.1, which refers to the number of speakers in the set (the ".1" refers to a subwoofer, which helps create bass rumbles). A 5.1 system uses five speakers: two on either side of the screen, one in the center just below the screen and two slightly to the rear of the viewer. A 7.1 system has all of the above, plus a pair of speakers on either side of the viewer. They allow the viewer to be absorbed into the environment. For instance, a scene with a plane flying overhead can play the sound of the engines on the front speakers, then move them to the rear speakers as the plane continues on its path, creating the illusion that it is flying overhead.

Receiver

Receivers are required for digital theater systems in order to receive the digital audio signals and send them to their respective speakers. Experts at Abby's Guide recommend a speaker with 40 to 80 watts for a smaller room and a full 80 watts for a larger room dedicated solely to the theater. Digital connections on the receiver should use surround sound formats -- usually either Dolby Digital or DTS -- and be compatible with your speakers. (In other words, it should have output jacks that match your speaker's input jacks.)

Other Components

Other components in a home theater system include DVD players, Blu-ray players, game consoles and cable or satellite receivers. You can connect them directly to the screen, or route them through the receiver, depending on the precise nature of your system. In each case, look for an HDMI connection, digital optical connection and/or fiber optic connection in the back of the component; all three allow signals to be sent digitally and should be clearly labeled so you can tell which is which.

Cables

Cables for a digital theater system need to be capable of conveying digital signals and should be compatible with the jacks on the two systems they're linking. HDMI cables carry both audio and video signals digitally, while fiber optic cables or digital optical cables are used to convey sound signals only.

References

• Home Theater Systems Advice
• Monster Cable: Home Theater Connection Guide