Instructions
Turn on your PS3 and a controller and press the "PS" button in the middle of your controller. Select ̶0;Settings̶1; and then ̶0;Sound Settings.̶1;
Choose ̶0;Audio Output Settings̶1; from the Sound Settings menu and select the type of connection you use to connect your PS3 (e.g., HDMI or Optical).
Select the bitstream audio output format you would like to use, such as ̶0;Dolby Digital 5.1 Ch.̶1; or ̶0;DTS 5.1 Ch.,̶1; instead of the default LPCM format, and save your settings. If you would like to try out a different format later on, repeat these steps and select a different audio output format.