I also have a 55 inch LG oled & a 42 inch pioneer plasma that we have tested the soundbar on and it works fine on these - unfortunately I don't have another device with optical output (that's easy to move) to plug in to our 65 inch, but the soundbar seems to work perfectly on the other TV's. I have made sure all the settings on the TV allow for optical output to the soundbar. The only thing I can think of is that this TV (and ideally the soudbar) is in an outdoor studio and the doesn't have at present have a wifi connection to our internet (it is out of range at present and too far from the modem for an ethernet connection). We have obviously set up the soundbar inside with internet connection and I can't see why the soundbars lack of Internet connectivity would have an issue with an optical connection to the TV. Can you please advise if this is a technical issue with the TV or the soundbar.... any help would be appreciated!
Best answer by Airgetlam
While you're in the TV's audio settings, you may want to check to see if they have a setting to turn on or off the optical output. Some TVs do, some do it automatically when you turn off the speakers, some have it on all the time and there's no option to do that. And if there's a setting in that location that allows you to switch between Fixed or Variable, make sure it's set to Fixed.
Then go in to all the devices that are connected, and do basically the same thing. Make sure that they're all set to Dolby Digital as well. This may be a problem for BluRay players, some of them don't have the option, and you have to either set it when you're watching a specific disc, or replace the BluRay player with one that does downmixing, as most BluRay discs are actually DTS, which can't be read by the PLAYBAR. There's a long thread in the Home Theater area of this board regarding which BluRay players actually can do downmixing.
Once you've done all this, you should be getting the necessary sound from the PLAYBAR.