Before revision: All 5.1 systems use the same speaker channels and configuration, having a front left and right, a center channel , two surround channels ( left and right ) and the low-frequency effects channel designed for a subwoofer.
After revision: All 5.1 systems use the same speaker channels and configuration, having a Front Left (FR) and Front Right (FR), a Center Channel (CNT) , two surround channels ( Surround Left - SL and Surround Right - SR(SW) ) and the low-frequency effects channel designed for a subwoofer.