Link to my lenghty post on the testing
Should have made a tl;dr in the first place. These refer to settings when using an LG OLED with the sharc.
* If you will send sound to an AVR and have other devices behind it that you'd like to keep using with the TV, disable CEC everywhere except Simlink on the LG as that needs to be on for eArc to work
* Set LG to use eArc, "Audio out" as Passthrough, "HDMI in" as bitstream
* Set your game console to output surround sound using Linear PCM to the correct number of channels you use
Now here's where you make your choice:
a. if you prioritize passing Dolby Atmos from internal WebOS apps and/or HD audio codecs from 4k bluray, leave Pin 1 on the shArc on the UP position. For stereo audio sources, you'll have to go into the LG sound settings and set the "audio out" option to PCM. And back to passthrough for surround sources.
b. if you don't have an Atmos capable sound system and would enjoy not having to fiddle with settings and just have everything work, set Pin 1 on the shArc to the DOWN position, and change the PS5 to decode bluray audio into Linear PCM (settings menu when playing a movie disc). You'll get surround sound from surround sources, and stereo sound from stereo sources, and non-lagged PCM from your game console and blurays.
Yes, you can get DD+ up to 7.1 with Atmos metadata from the Netflix app, but the youtube app only seems to be able to produce stereo sound, regardless of your setup.
But you can do this on regular ARC, you don't need the sharc for it. In fact, the sharc makes it worse as you'd have to keep changing settings to go from getting DD+ from Netflix to using the youtube app and back.
Personally I've never been able to get anything but stereo on YouTube regardless of the app I use for it on whatever device or tv I've had. Currently using a LG CX with ShARC. I got both in October.
For me the ShARC is working and has been after the first week I got it. I use a Denon 4200 AVR with it. But I have nothing connected to the AVR apart from ShARC. Everything else is connected to back of tv.
My PS5 on hdmi 1, PC in hdmi 3 and a few other devices like switch and Apple tv, PS3 on hdmi 4 using a hdmi switcher.
I did get the endless black screen cec loop at the start when I got the ShARC. and tbh I have no idea how I fixed it other than doing a hard factory restore of the tv (was the only way I could fix it) I disabled cec in my avr and other stuff but I dunno if I disabled it properly I still got that issue even afterwards. It was a nightmare as it was making me go insane thinking my tv was faulty or something lol.
So I just plugged everything out of the avr, except the ShARC, and into the tv just before I did the factory restore and now it seems to be working fine.
There are minor quirks like a handshake issue where I have to switch on the avr first and let it power on completely before switching on the CX. otherwise I won't get sound sometimes unless I turn them off and turn on in the correct order. Nothing major I got used to it already and it's just once a day I switch them on anyway. I leave my avr on all day when I switched on and only switch it off at night before bed. So it's no big deal.
I don't really know the difference between Dolby digital + and just Dolby digital but all the video CX apps play in dd+ Except YouTube which plays in stereo. It used to play all these like this even on my last tv a Samsung KS800 in DD+ or stereo on YouTube even without a ShARC, so it's working exactly like before.
If I use Netflix, Disney plus, Amazon video apps etc outside the webOS, on say ps5 or my Apple TV they seem to play uncompressed lossless audio and Atmos or any other format the video is supposed to play in so the ShARC works and passes this through correctly.
Most of the time I just use the tv apps for the video stuff though tbh as it's a lot faster loading. I don't care if I don't get 5.1 on YouTube as it's just short videos I watch. The YouTube app is great on the CX too. soooo fast compared to any other YouTube app on other devices and it's so seamless to switch between that and Netflix etc so the trade off is kinda worth it.
Unless I'm watching a snazzy HD film that deserves to be heard with proper Atmos sound with the picture I'll use the the Apple TV or PS5 but I normally stick to the tv apps.
Have a minor issue with Dolby Atmos content though, where it cuts the audio out of that device on stereo stuff after playing Atmos content but I believe LG are working on a fix. It's been well documented everyone gets this problem apparently. A reboot of the tv fixes the issue currently but can easily replicate it.
Also very occasionally on the pc hdmi input it did exhibit that popping sound people mentioned here when sound plays at the start of anything but this has happened like 3 times since I've had the ShARC so it's very rare. I use my pc every day too. Restarting the pc seems to always fix it anyway. Looks like a handshake issue or something. It's never happened on my other devices either.
Other than that it all seems to be working now for the past couple of months without any issues. Get perfect sound on my devices. Lag free and lossless.
I just hope a firmware update from LG for the CX doesn't break something in terms of passing audio through somewhere.
I don't think I'm gonna update the ShARC either, as it's all working fine and I don't wanna mess up something if I update it tbh.