What Is Surround Sound Audio?

The definition of surround sound and differences between systems

Surround sound audio is, simply put, sound that surrounds you. It means a speaker in virtually every corner of the room, projecting high-quality digital sound at you from all angles, just like in a movie theater.

Surround Sound Audio and Sound Diversification

Surround sound audio also means sound diversification, with deep, thunderous bass rumbling the floorboards as an explosion happens on screen and subtle sound effects skittering and tapping behind you in a suspenseful scene. For music, it means the complete sonic envelopment of a song.

A surround sound system includes a set of speakers—usually five, including the center speaker—and a subwoofer for powerful bass. This is where the term "5.1" comes from: five speakers and a subwoofer.

If you're interested in buying a surround sound system, be sure to read the definitions below, as well as the breakdown of how the different parts work.

Components of a Surround Sound Speaker System

A typical surround sound speaker system has several core components.


A subwoofer is a large, powered speaker that produces bass tones and other low-frequency sounds. A subwoofer uses air pressure to create a deep, rumbling sound to fill a room with bass. Subwoofers are most often placed on the floor in the corner of a room or theater for maximum effect.

When you're in a room or theater with loud bass that makes the floor rumble, that's the subwoofer you're feeling. On a PC surround sound system, a subwoofer helps create fantastic bass tones when playing music or a particularly exciting movie.

Center Speaker

The center speaker in a surround sound system is often considered the most important speaker of all the speakers in a surround sound system. It is usually larger, more versatile, and contains more individual speaker cones than the satellite speakers.

Most of the important sound—such as dialogue and key sound effects—is channeled through this speaker. High-quality surround sound systems have a center speaker that is different from the left and right satellites.

Satellite Speakers

A satellite speaker is a general term used for any of the speakers meant to be placed on the left or right sides of the room. In a standard 5.1 system, this means the left and right front speakers and the left and right rear speakers. That's a total of four speakers plus the center speaker, which makes five. The ".1" represents the subwoofer, which is how the term "5.1" developed. "6.1" surround sound means six speakers plus one subwoofer.

Equalizer or Mixer

Usually, the equalizer or mixer will be a part of your PC (or audio receiver, for home theaters). Most computers have built-in equalizers or mixers as part of the sound card output specs. Most audio software, such as iTunes, also comes with a mixer. On high-end systems, or on systems that require a lot of power, you may need a separate equalizer as part of a powered amplification system.

Types of Surround Sound Speaker Systems

There are several typical types of surround sound speaker systems:

2.1 Speaker Systems

2.1 audio systems are not technically surround sound, but they are a step up from simple shelf speakers (which don't have the benefit of a subwoofer). As with 5.1 systems, the "2" stands for two satellite speakers, at the left and right front, and the ".1" stands for the subwoofer.

So 2.1 sound is a great economic solution if you don't have the money or space for what is called "true" surround sound (at least 5.1 speakers), but you still want high-quality, dynamic sound.

5.1 Surround Sound Speakers

5.1 surround sound is often referred to as "true" surround sound. This is because the five speakers allow for two left and right front speakers, two left and right rear speakers (behind your head), a quality center speaker, and a powered subwoofer for deep, rumbling bass tones.

When digital surround sound signals (such as Dolby or THX) are played through a system like this, you enter a new realm of sound, with thundering explosions, dynamic music, and subtle, encompassing sound effects all around your room.

6.1, 10.2, and other Multi-Speaker Systems

5.1 surround sound is considered the minimum number of speakers needed for true surround sound. Other common configurations include 6.1 (six speakers and a subwoofer) or 10.2 (ten speakers and two subwoofers).

The configuration doesn't matter a great deal and is mostly dependent upon your room size and personal desire. Most audio experts will tell you that you only need to ensure that the speakers are balanced on each side of the room. In a 6.1 system, the extra satellite usually goes at the back center of the room, to balance out the front center speaker.

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