LG LHT764

The first step is to make sure that all of your speakers are functioning properly and are wired in the correct place. To do this, turn on your TV and receiver, and hit "SETUP" on your remote. Step down and select "Audio" from the list on the left, and select "5.1 Speaker Setup" from the menu on the right. Scroll down to "TEST" and step through each speaker using the right and left arrow keys on your remote, ensuring that each speaker is functioning properly. Exit out of the "SETUP" menu when finished.

Now, when you have a source that you would like to hear on 5.1 channels, but is encoded in 2.1, hit the "SOUND" button on your remote until "PL II MOVIE" or "PL II MUSIC" is displayed on your screen. This stands for Dolby Pro Logic II, and is the way that your receiver multiplexes a 2-channel signal.