Samsung PN51E6500EFXZA - Manual (Page 622)

separate audio cable is required.
If your TV has a headphone jack, make
sure there is nothing plugged into it.
If the TV is connected to an external
device, reboot the connected device by
disconnecting, and then reconnecting
the device’s power cable.
The speakers are making an inappropriate
noise.
Check cable connections. Make sure
a video cable is not connected to an