I can't get ARC to work at all. I set the sound output to ARC on the TV. Simplex turns on by itself. But it won't output to my AvBox audio extractor. I know the box works because I tested it with a different model TV (samsung) with ARC and it worked perfectly. When I turn on ARC on the LG, the internal speakers cut out, but no sound comes through the HDMI-ARC cable.