Home theater is difficult to define — it’s really just a vague term for a particular approach to home entertainment. Generally speaking, a home theater system is a combination of electronic components designed to recreate the experience of watching a movie in a theater. When you watch a movie on a home theater system, you are more immersed in the experience than when you watch one on an ordinary television. The basic idea of a home theater is to recreate these elements with home equipment. The main thing that sets a home theater apart from an ordinary television setup is the surround sound. For a proper surround-sound system, you need two to three speakers in front of you and two to three speakers to your sides or behind you. The audio signal is split into multiple channels so that different sound information comes out of the various speakers. The most prominent sounds come out of the front speakers. When someone or something is making noise on the left side of the screen, you hear it more from a speaker to the left of the screen. When something is happening on the right, you hear it more from a speaker to the right of the screen. The third speaker sits in the center, just under or above the screen. This center speaker is very important because it anchors the sound coming from the left and right speakers — it plays all the dialogue and front sound effects so that they seem to be coming from the center of your television screen, rather than from the sides. The speakers behind you fill in various sorts of background noise in the movie — dogs barking, rushing water, the sound of a plane overhead. They also work with the speakers in front of you to give the sensation of movement — a sound starts from the front and then moves behind you. The audio/video receiver is the real heart of a home theater. The audio/video (a/v) receiver and amplifier assembly in a home theater does the same job as the receiver and amplifier assembly in any stereo system: It receives signals from various input devices, like a VCR, DVD player or satellite dish. It interprets and amplifies those signals and then sends them to output devices — your television and sound system. A home theater a/v receiver and amplifier assembly actually combines several different components. Some even have a DVD or other media player built in. You can generally assemble a superior home theater system by buying the components separately, but most people buy one unit that does all these jobs because it is more cost effective.