Instructions
Check your TV's sound settings. Make sure the muting function is turned off. If you are unsure, press the "Mute" button on your remote or TV to see if it's turned off.
Check your TV's volume level. Press the "Volume Up" button on your remote control or TV repeatedly to increase the volume.
Change the AV cable. Your current one may be faulty. Make sure the cables are properly connected to the right inputs. If you're using AV cables, make sure the red and white jacks are connected to the red and white inputs on your TV. If you are using an HDMI cable, make sure it's properly connected to the HDMI port on your TV.
Select "Settings" on your PS3's main menu, select "Sound Settings" and then select "Audio Output Settings." Make sure the audio settings match the AV cable or the audio connection method you're using.