Samsung UN55ES8000G E-Manual page 717

Check the volume setting of the device
(Cable/Sat Box, DVD, Blu-ray etc.)
connected to your TV.
The picture is good but there is no sound.
Set the Speaker Select option to TV
Speaker in the Sound menu.
If you are using an external device,
check the device's audio output option.
(Ex. You may need to change your
cable box's audio option to HDMI if