SOUND-BAR Speakers come in two types, one is intended to add the (missing) CENTER speaker for a 3.1 or a 5.1 sound system. The second is a style that has multiple speakers in one enclosure and has the decoding electronics for a 5.1 sound system all in one self contained unit and makes the listener think some of the sound is coming from a place, from the sides and/or back, where there are no actual speakers through a kind of PHASE control.