OTHER TECH

5.1-channel A 5.1-channel receiver decodes and powers the five main channels (left, center, and right front plus left and right surround) in a surround sound system and sends deep bass from the ".1" channel to a powered subwoofer. Most 5.1 systems consist of five speakers plus a subwoofer, but a sub can be built into one or more of the other speakers.

back surround One or two speakers that you place behind your main seating area to reproduce the channel centered between the left and right surround speakers.

bipole speaker Radiates equally and in phase in two directions, creating an open, but focused, sound.

crossover Separates the audio signal according to frequency - for instance, the lower, bass frequencies go to a woofer while the higher frequencies are sent to a tweeter.

dipole speaker Radiates equally in two directions, but out of phase, creating a diffuse sound; often used for surround speakers.

multichannel analog audio input The six (sometimes eight) input jacks on a receiver that accept the signals for each surround sound channel in the high-resolution mixes on DVD-Audio discs or SACDs.

power tower A floor-standing speaker with a powered subwoofer built in (see "tower speaker").

satellite speaker Any speaker that relies on a subwoofer to reproduce the deep bass; usually refers to the main speakers in a sub/sat system.

sensitivity A measure of how efficiently a speaker uses power from an amplifier, expressed in decibels (dB). The higher the number, the more sensitive the speaker, meaning it doesn't need as much power to achieve the same volume as a less-sensitive speaker.

6.1- and 7.1-channel A receiver that can decode a back surround channel from a Dolby Digital EX or DTS-ES soundtrack and amplify it for one or two speakers. The receiver might also have processing to change the single recorded back surround channel into two separate channels or to add a back surround to program sources that don't have one.

tower speaker A floor-standing speaker, as opposed to a bookshelf model.