The surround sound amplifier is an electronic device for home theater systems that processes sound from an input device for delivery to a speaker configuration. The device essentially controls the audio quality, volume, and channeling of the signal. Typical units are also known as audio/video (AV) receivers. These integrated units combine sound processors such as compact disc (CD) and digital video disc (DVD) players with amplification technology. Higher-quality dedicated components split processing/amplification functions into separate units, and are known as separates.
An integrated surround sound amplifier manages all the processes, allowing users to add preferred input devices. The heart of any home theater system, the amplifier works in conjunction with a full set of speakers encircling the room. The two common types of immersive audio configurations include 5.1 and 7.1 surround sound. Both feature speaker placements at left, right, and center of the screen, with additional left and right speakers for the surround effects to indicate three-dimensional space through the use of audible cues. The 7.1 surround adds another pair of speakers for placement on either side behind the person.
The additional 0.1 aspect of the surround sound system indicates the subwoofer, usually the larger unit, which gives depth and bass to the bottom audio ranges. The integrated surround sound amplifier is often the more easily configured. Separate processors with pre-out jacks, however, offer the choice of upgrading to more powerful amplifiers in the future.
Some higher-end products may offer 100–400 watts per channel. While use typically centers around the 15-50 watt range, the greater capacity wattage of a 100-watt channel allows the output to remain on the linear portion of the distortion curve. Sound quality and special effects will be of greater quality and impact when driven by the higher-power capacities.
Surround sound amplifier connector jacks consist of the garden variety of stereo and theater components. These may include jacks for radio tuners, digital audio and video players, television, and various AV recording devices. Coax and optical audio inputs accommodate DVD, CD, and even satellite tuners. Additional jacks fit more contemporary, high-definition (HD) signal technologies. There may even be inputs for older technologies such as phonographs and cassette players.
The integrated surround sound amplifier tends to be less expensive, as it is mass produced and marketed in order to keep the unit costs low. Separate sound processors and preamps are usually manufactured in smaller numbers, and often are of higher quality. Many power amplifiers have three to seven different channels available on one unit. As the amplifier represents the power base of the home audio system, users should invest more carefully in this unit than in interchangeable peripheral components.