In any multiple-speaker audio system -- whether or not it involves surround sound -- you'll have to connect rear speakers to make everything work as intended. The term "rear speakers" is often used as a catch-all to describe multiple speaker functions. For example, many receivers use the same output terminals for multiple auxiliary speaker outputs, with these jacks labeled "Speaker B," "Zone 2" or "Surround." There are many ways of getting sound from these jacks, including the use of wireless options if necessary.
Conventional Surround Sound
The most common application for rear speakers is when used in a surround environment. In these cases, rear speaker outputs may be labeled "Surround" or "Surround Back." The former is used in standard 5.1-channel surround setups, featuring one pair of surround speakers to the sides or rear. Surround back speakers are used in conjunction with standard surround speakers in 7.1-channel environments, with the surrounds placed to the sides and the surround backs located behind the listening position. When the surround back terminals aren't used for this application, they may often be re-assigned for stereo music output in a separate room through the receiver's menu system.
Stereo "B" Speakers
Conventional stereo receivers normally feature a "B" speaker output. This is designed to output the same audio information as the "A" speakers in the main listening area, perhaps in the back of the room or in another space entirely. The "A" and "B" speaker outputs share the same volume level and amplifier. In simple multi-zone audio systems, the "A" or "B" speaker outputs are fed to a speaker selector box, with each individual speaker pair wired to the selector. This allows stereo sound outside, in the den, living room or other multiple spaces using a basic receiver and audio source, like a portable media player or CD player.
Some environments aren't friendly for running wires. Lofts, homes built on concrete slabs and older homes featuring plaster and lathe are notoriously hard to cleanly route new speaker wire through. Enter wireless speakers. These systems feature a small transmitter box that connects to the rear speaker output terminals on the receiver, similar to how a conventional pair of speakers would connect. The box then sends the audio signal from the receiver to a pair of remote speakers up to 100 feet away. Bluetooth wireless speakers are another option, but their range is typically shortened to around 30 feet. The catch with these systems is that the speakers must also be powered -- either through the use of batteries, or plugging them into an AC outlet. Wireless speakers may be used for stereo output or surround sound duty, the same as any other conventional pair of wired speakers.
No matter what you use the rear speaker outputs for, there are certain practices that provide the best sound and reliability. Speaker wire insulation, for example, should only be stripped enough to expose enough wire to fit into the binding post or spring terminals without leaving exposed copper. This prevents accidental short circuits from contact with the chassis of the receiver or another exposed wire. Crimp or screw-on banana plugs make wire connections easier, while preventing air exposure from oxidizing the copper underneath. The actual speaker wire should be of sufficient gauge to carry the audio signal without significant loss from resistance. For example, up to 100 feet, 16-gauge wire is sufficient. Beyond this distance, 14- or 12-gauge wire should be chosen. If the wires are running through the walls, CL-rated wire must be selected. This specialized wire meets electrical code, featuring a jacket that won't emit noxious fumes or conduct fire from one space to the next.
- Medioimages/Photodisc/Photodisc/Getty Images