Surround Sound

Surround sound systems separate an audio signal into multiple speakers. There are usually four to seven speakers that play different ranges of music for a deeper field of sound.

Surround sound systems add additional speakers to audio or home theater systems in order to create a more realistic field of sound. Whether the listener is in a small living room or a large theatre, surround sound allows sounds to come from different places within the room. For example, if a movie is playing a scene where a car drives by, surround sound systems allow the sound to begin in the back of the room and move toward the front of the room as the car on the movie drives by. Most surround sound systems have rear speakers that play ambient noises and special effects, and they employ a center speaker that plays dialog or vocals.

Besides adding additional speakers to home stereo systems, surround sound systems separate different ranges or frequencies of sounds into different channels. In the 1950s, stereophonic sound, or "stereo" was commercially introduced as a vast improvement over "mono" sound. Early stereo systems and current surround systems operate via a similar principle of separating ranges of sounds into different channels. Whereas stereo systems separate different sounds into two channels, most surround sound systems separate sounds into four or more channels. Some movie theater surround sound systems separate seven channels of sound into eight or more speakers.

The biggest drawback to the basic stereo audio system is that most people position their two speakers side by side in the front of the room. This creates a flat sound since the listener hears sounds coming from only one direction. In the 1970s, beginning with films such as Star Wars, Dolby Labs began setting the standards for today's surround sound systems. These early surround sound systems were operating primarily in theaters, where listeners were astonished to hear sounds such as the Millennium Falcon passing from the left rear theater speakers through the right front speakers. With each surround sound speaker making a separate part of the sound spectrum, the combined effect of the multiple speakers was a richer, fuller field of sound. The popularity of Dolby's surround sound systems allowed the company to create home audio and theater surround sound systems.