If you've performed a Factory Data Reset, you'll need to turn on the Surround Sound feature.
- Press the Home button on your remote.
- Navigate down to Settings and select it.
- Navigate down to "Sound" and select it.
- Navigate down to "Surround Sound" and select it.
- Now make your choice of "Auto", "Always", or "Never".
- Now press the 'Home' button and use normally.