A conventional stereo system provides two audio channels, left and right, which are reproduced by the left and right loudspeakers. When correctly set up, two channels of information driving two loudspeakers produce a sound field in front of the listener that seems to exist between and around the two loudspeakers.

A home theater system provides multiple cannels, each channel feeding a loudspeaker located in front of, alongside, and for behind the listening / viewing position. Specifically, a home-theater system has three front loudspeakers located across the front of the room, and two, three, or four surround loudspeakers behind or to the side of the listening position.

The surround loudspeakers have a different job. They are generally smaller than the front loudspeakers, and handle much less energy. Consequently, they can be mounted unobtrusively on or inside a w. Surround speakers mostly reproduce "atmospheric" or ambient sounds, creating a diffuse aural atmosphere around the listener. In a jungle scene, for example, the surround loudspeakers would recreate sounds such as chirping birds, falling raindrops, and blowing wind; - a city scene, the viewer would be surrounded by traffic sounds. The surround loudspeakers' contribution is subtle, but vitally important to the overall experience. Correctly set-up surround loudspeakers should not be able to be heard directly, but should instead envelop the view- a diffuse sound field.