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How Many Channels do You Need?

Stereo and Multichannel Sound


An Overview of 2.0, 2.1, 5.1, 6.1, and 7.1 Channel Systems

  • 2.0 Channel Stereo Systems

    A basic stereo system (2.0) consists of two-channels of sound produced by stereo speakers, left and right channels powered by a stereo receiver or amplifier. A 2.1 channel system includes a subwoofer with the stereo speakers.

    Stereo Component Reviews

    More About 2.1 Channel Systems

  • 5.1 Channel Home Theater Systems

    A/V receivers are distinguished from two-channel or stereo receivers by having five or more amplifier channels for movie theater sound or multichannel music ( DVD-Audio and SACD discs) in your home. A basic home theater system consists of 5.1 channels (or more) of sound. The five-point-one channels are left and right, like a stereo system, a center channel for movie dialog or music vocals and on-screen sound, and left and right surround channels, for special effects and surround sound. An additional subwoofer channel (the .1 or LFE channel, Low Frequency Effects) adds very low bass for music sources and special effects on DVD movie sound tracks. The composite of the five main channels plus a subwoofer channel produces a “soundfield” that envelops the listener with sound coming from in front of and behind the listenerMost DVD discs and other multichannel sources are encoded in Dolby Digital 5.1 and/or DTS 5.1 channel sound for playback on home theater systems. .

  • 6.1 Channel Home Theater Systems

    6.1 channel systems have an additional rear-center channel speaker for a total of three front and three rear speakers. 6.1 channel sound provides more precise positioning of sound effects and creates a more enveloping soundfield. Sound effects such as airplane flyovers that go directly overhead can sound more realistic with a 6.1 channel system. Some DVDs are encoded with 6.1 channel Dolby Digital EX and DTS-ES sound, and can be played back on this type of system.

  • 7.1 Channel Home Theater Systems

    7.1 channel receivers have three front channels, two surround channels and two surround-back channels, plus a subwoofer channel. The additional rear surround channels produce a soundfield with more precise placement of surround sound effects. Some 7.1 channel receivers offer THX™ soundfield enhancement, which is a system developed by Lucas Film™ designed to present film sound or multi-channel music with the most authentic quality. THX processing is offered as Select or the more advanced Ultra 2 format, which is optimized for movies and multi-channel music. Many other manufacturers have proprietary soundfield programs, called DSP (Digital Signal Processing, which also provide soundfield enhancements for music and movies. Sony, for example, has Digital Cinema Sound™ and Yamaha has Cinema DSP™.

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