Having distorted unrecognizable audio from my LG 65 UH8500 TV's optical out in some scenarios.

Hi All, I have LG 65UH8500 TV (recently purchased so I still have return window), I wanted to use my wireless headphone with it which has 3.5mm jack, my TV only supports optical output along with TV internal speakers, there are no headphone jack. So I had to buy Optical to Analog converter from amazon. Check below my findings when using 3.5mm audio out from my converter:

1. Its working fine when playing XBox One connected to TV via HDMI.
2. Having horrible noise when watching TV using antenna.
3. When using TV USB, mp3 music is playing fine, AVI video's audio is fine but MKV video's audio was again chunk of noise, if needed I can check and share audio formats.

In all above scenarios TV internal speakers playing perfectly, I wanted both audio as I like louder so needed head phones and my wife needs casual TV sound.

It feels like some audio format issue but very confusing as TV speakers has no issue but optical output is having feedback distortion, this is completely new experience for me using optical audio out so no idea where to look. Any ideas/help will be greatly appreciated.

It seems that it works when the source is 2 channel but not 5.1
Check the TV audio menu to see if you can change the digital audio output type.
Most optical to analog converters will not accept a 5.1 channel input. It might output noise when receiving 5.1

^I agree. Your converter box suppose to ignore 5.1 signal, but if it's a cheapy box, it tries to interpret something it doesn't understand. Set TV for PCM output, not Dolby, and if there is a setting nearby that says Downsample, say YES.