Originally Posted by Steve S
Like the vast majority of tvs the LG won't output 5.1 via it's optical digital output from external source devices, only when using the set's own digital tuner and only when tuned to a channel broadcasting in 5.1. You can run optical cables from source devices directly to your AVR in addition to HDMI to the set.
My Xbox to the TV to the receiver=DD
Stream movies from PC to the TV to the receiver=DD
Stream from USB to TV to receiver=DD
Sony Bluray to the TV to the receiver=stereo
DTV to the TV to the Receiver=stereo
I have an old JBL with only 2 optical in and no HDMI.