Samsung UN55ES8000G E-Manual page 691

output from the TV's Optical jack.
When the TV is displaying a DTV
(air) signal, the TV will send out 5.1
channel sound to the receiver. When
the source is a digital component
such as a DVD player and it is
connected to the TV via HDMI, you
will hear only 2 channel sound from
the receiver.
Using the ARC function