Surround sound means just what it says, sound that surrounds you. Surround sound in your home is designed to create an immersive audio experience that surrounds you in the events shown on screen, just like it does in the movie theater. To achieve this goal, different types of surround sound systems have been created with special speaker placement, these systems are summarized below.
2.0 channel sound systems. Better known as "stereo" this is the most basic of modern-day systems, and it requires a minimum of two speakers (left and right of the listening position).
2.1 channel sound systems. This "stereo" system is an expansion of 2.0 with the addition of a subwoofer (.1).
3.1 channel surround sound systems. This system is the same as 2.1 but includes a center channel (typically focused on vocals and effects taking place on-screen). The two other speakers would be placed left and right of the listening position as in a 2.0 or 2.1 configuration.
5.1 surround sound speaker systems. Better known as "Dolby Digital™" which is the most common name for six-channel surround sound audio systems which use five full-bandwidth effects speakers (5) and one low-frequency effects (LFE) subwoofer (.1). Three of the speakers are used for the front left, center and right with the remaining two speakers placed towards the rear and sides of the listening position. All effects speakers project discrete surround channels encoded in a 5.1 soundtrack which are designed to immerse the listener in a surround experience. The 5.1/Dolby Digital surround sound system is currently the most common of all surround sound system formats today, due to the continued use and proliferation of DVD, Blu-ray™ soundtrack requirement, and broadcast of Dolby Digital audio. Dolby Atmos® enabled speakers can be added to a 5.1 system to create either 5.1.2 or 5.1.4 surround sound configurations with the additional effects channels positioned in the ceiling, just forward and rearward of the listening position.
7.1 surround sound speaker systems. An expansion of Dolby Digital/5.1, 7.1 is an eight-channel surround audio system commonly used in home theater configurations. This system adds another two surround speakers which are placed to the sides or behind the listening position. These speakers add discrete enhanced surround effects information. As with a 5.1 surround sound system, 7.1 surround sound systems borrow the same front left, center, and right effects channels and LFE speaker configuration. Where a 5.1 surround sound system's rear channel effects are limited to two channels, a 7.1 surround system splits the surround and rear channel information into four discrete channels in which sound effects are directed to left and right surround channels, and/or two rear surround channels. In a 7.1 surround sound home theater setup, the surround speakers are placed to the sides of the listening position and the rear speakers are placed behind the listening position. Dolby Atmos enabled speakers can be added to a 7.1 system to create either 7.1.2 or 7.1.4 surround sound configurations with the additional effects channels positioned in the ceiling, just forward and rearward of the listening position.
See examples of 5.1 and 7.1 surround sound system layouts here.
Dolby, Dolby Atmos are registered trademarks of Dolby Laboratories. Dolby Audio, Dolby Digital are trademarks of Dolby Laboratories. Blu-ray is a trademark of the Blu-ray Disc Association.