A 5.1 surround system has five discrete audio channels: Left, Right, Center, Left Surround, Right Surround and the Subwoofer.
Front Left & Right Speakers (L & R): Place the Front Left and Right speakers at ear height, producing a 45° angle as viewed from the main seating position. This delivers a wide soundstage and precise localization of individual sounds.
Center Channel Speaker (C): Place the Center channel speaker either above or below the TV. Then, aim the speaker either up or down to point directly at the listener. If you have a perforated projection screen, center this speaker both horizontally and vertically behind the screen.
Left Surround and Right Surround Speakers (Ls & Rs): Place the Ls & Rs speakers between 90° to 110° to each side and 2 feet or higher above the listener. The Ls & Rs speakers recreate the enveloping sound and intense special effects that you experience in the cinema.
Subwoofer (Sub): If you have two Subs, put them in the middle of opposing walls. If you have one, place it in the middle of the front wall.