A 7.1 surround system has seven discrete audio channels, Left, Right, Center, Left Surround, Right Surround, Left and Right Back, and of course, 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 seat. 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 display. 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.
Rear Surround Left & Rear Surround Right Speakers (Rrs & Rls):
Subwoofer (Sub): There are a few variations for subwoofer placement, depending on how many subwoofers you have in your room. If you have four subs, place one in the middle of each wall. If you have two, put them in the middle of opposing walls. If you have one, place it in the middle of the front wall.