Extracts 4 audio channels from a stereo source:
- Two for speakers at the front - left (L) and right (R).
- Two for surround speakers at the rear - surround left (LS) and surround right (RS).
- Describes the early matrixed Surround Quadraphonic, Quadraphonic Stereo and other systems.
- Surround Sound speaker placement: The front speakers should be placed at the edges of the screen, toed in to face the central listening location, and the tweeters should be ear height. Rear channel speaker should be placed high on the back wall, slightly behind the listening position, and can be of smaller size, due to the frequency limitations of the surround channel.
