Home Theater & Entertainment Audio Monophonic, Stereophonic and Surround Sound Differences Expand your home theater system with additional speakers By Gary Altunian Writer Gary Altunian was a freelance contributor to Lifewire and industry veteran in consumer electronics. He passion was home audio and theater systems. our editorial process Gary Altunian Updated February 27, 2020 Frederico Rostagno Audio Speakers Stereos & Receivers Tweet Share Email Monophonic, stereophonic, multichannel, and surround sound represent the four main types of audio you'll encounter in home theater systems. Monophonic Sound Monophonic sound is created by one channel or speaker and is also known as monaural or high-fidelity sound. Monophonic sound was replaced by stereo or stereophonic sound in the 1960s. Stereophonic Sound Stereo or stereophonic sound is created by two independent audio channels or speakers and provides a sense of directionality because sounds emanate from different directions. Stereo sound reproduces sounds and music from various directions or positions the way we hear things naturally, hence the term solid sound. Stereo sound is a common form of sound reproduction. Multichannel Surround Sound Multichannel sound, also known as surround sound, is created by at least four and up to seven independent audio channels or speakers placed in front of and behind the listener that surround the listener in sound. Multichannel sound can be enjoyed on DVD music discs, DVD movies, and some CDs. Multichannel sound began in the 1970s with the introduction of Quadraphonic sound, also known as Quad. Multichannel sound is also known as 5.1, 6.1, or 7.1 channel sound. 5.1, 6.1, and 7.1 Channel Sound Here's a description of the three common multichannel surround sound speaker setups for a home theater system and how these setups are best used. 5.1 channel sound is an industry standard sound format for movies and music with five main channels of sound and a sixth subwoofer channel (called the point-one channel) used for special movie effects and bass for music. A 5.1 channel system consists of a stereo pair of speakers, a center channel speaker placed between the stereo speakers, and two surround sound speakers located behind the listener. 5.1 channel sound is found on DVD movie and music discs and some CDs. 6.1 channel sound is a sound enhancement to 5.1 channel sound with an additional center surround sound speaker located between the two surround sound speakers directly behind the listener. 6.1 channel sound produces a more enveloping surround sound experience. 7.1 channel sound is a further sound enhancement to 5.1 channel sound with two additional side-surround speakers located to the sides of the listener’s seating position. 7.1 channel sound is used for greater sound envelopment and more accurate positioning of sounds.