A Guide to Monaural, Stereo, Multichannel, and Surround Sound

Stereo still dominates the field

Anyone interested in audio systems needs to be familiar with a few terms, among them monaural, stereo, multichannel, and surround sound. If shopping for audio components leaves you confused, learn these terms, which all audiophiles should know.

Monaural Sound Is a Thing of the Past

Monaural sound is a single channel or track of sound created by one speaker. It is also known as monophonic sound or high-fidelity sound. Monaural sound was replaced by stereo or stereophonic sound in the 1950s, so you are unlikely to run into any monaural equipment for your home.

Stereo Sound Is the Most Common

Stereo or stereophonic sound consists of two separate audio channels or tracks of sound reproduced by two speakers. Stereo sound provides a sense of directionality because different sounds can be heard from the speakers. Stereo sound is still the most common form of sound reproduction in use today.

If you have any audio equipment at all, you are likely familiar with stereo sound. Stereo systems are referred to as 2.0 channel systems (or 2.1 if a subwoofer is added). Unless you plan to venture into high-end home theater territory, stereo is most likely the type of audio equipment you need for your home.

A modern living room with wall-mounted TV, stereo speakers, and a couch.

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Surround Sound / Multichannel Audio

Surround sound, also known as multichannel audio, is created by multiple independent audio channels and speakers placed in front of and behind the listener. The purpose is to surround the listener with the sound recorded on DVD music discs, DVD movies, and some CDs. Surround sound became popular in the 1970s with the introduction of quadraphonic sound, also known as quad.

Since that time, surround sound or multichannel sound has evolved and is used in upscale home theater systems. The most popular surround sound configurations are 5.1, 6.1, and 7.1 channel sound. You need to know the difference before you shop.

5.1 Channel Sound

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), which is used for movie special effects and bass for music.

A 5.1 channel system consists of a stereo pair of front 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. The two most common 5.1 channel formats are Dolby Digital 5.1 and DTS Digital Surround.

6.1 Channel Sound

6.1 channel sound is a sound enhancement to 5.1 channel sound. It adds 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. Typically, this system is designed for DTS-ES, Dolby Digital EX, and THX Surround EX.

7.1 Channel Sound

7.1 channel sound is a further sound enhancement to 5.1 channel sound with two additional side surround speakers located on the sides of the listener's seating position. 7.1 channel sound is used for greater sound envelopment and more accurate positioning of sounds.

7.1 audio formats are the most detailed of all with DTS-HD Master Audio and Dolby TrueHD. These formats are not compressed and are identical to the original studio recording. A 7.1 configuration also delivers excellent quality with DTS-HD and Dolby Digital Plus, although it isn't lossless sound.

Which Surround Sound Configuration Is Better?

If money and space for a home theater setup are no object, the 7.1 channel sound is a clear winner, but many people don't have room for the eight speakers a 7.1 system requires. In a normal size room, a 5.1 system does a great job (at a lower cost). It's easier to set up and compatible with a wide range of technology. All the surround sound configurations deliver excellent quality.

Beyond 7.1

The adventurous can keep adding speakers as long as they have a receiver to handle them (9 channel and 11 channel receivers are available), but the technical requirements are high and the setup isn't for the faint of heart. It's questionable whether anyone needs that level of technology in a home theater.

Another twist on configurations adds vertical channels courtesy of Dolby Atmos. So a 5.1.2 configuration contains five regular speakers, one subwoofer, and two vertical channels designed for overhead speakers.

You only need to look at Auro 3D Audio or DTS:X immersive surround sound format to realize that audio technology isn't standing still.

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