alpine kettle
Thought I'd try posting here about this issue, because why not, we do ask everyone with issues to post them here 😛
Some background information: I have now a new LG OLED C2 TV with which I want to take advantage of some of the Series X features such as 120 Hz and VRR.
And I have a Samsung Q950T Dolby Atmos soundbar from before.
The ideal setup I'm trying for is Series X -> via HDMI 2.1 -> TV, and then the TV -> via HDMI eARC -> Soundbar.
The TV's settings are set to send audio via eARC to the soundbar via HDMI bitstream. On Xbox I have audio passthrough enabled.
But when I do this, and I select the "Dolby Atmos for Home Cinema" option on the Series X's audio settings, I get a VERY noticeable audio delay, measured even as high as 300-400 ms. Everything else is working properly (Dolby Atmos content plays as intended, each speaker sending the right signal, the Dolby Access app detects a correct setup...), but the audio delay is apparent on all content, from the Xbox dashboard sounds to games and streaming apps.
Now though, there's a setting on the TV which allows me to change the Digital Sound Output to Auto, PCM or Pass Through. Both Auto and PCM cause audio delays. Changing to Pass Through causes the Dolby Atmos for Home Cinema setting to disappear from the Xbox settings. This is quite odd, since the recommended set up would be that both Xbox and TV are set to passthrough so it's the soundbar that does all the audio decoding, to my understanding.
Other bitstream audio formats such as Dolby Digital also have an audio delay, though it's a bit smaller (200 ms). Uncompressed audio formats such as surround 5.1 and 7.1 work as intended with no delay whatsoever, and the test audio option in Xbox plays all sounds for each speaker correctly.
I have reported the issue from the console itself already.
As some added notes, I'm on the Xbox Insider Alpha ring.
Additionally, I normally have a Philips HDMI Sync Box between the Series X and the TV to sync up my living rooms Philips Hue lights. But for the purpose of troubleshooting this issue I have tried as well with both this box in and out of the device chain.
Finally, I should point out that connecting the Series X directly to the soundbar, which supports video passthrough to the TV, works just fine, and Atmos content will play as intended with no delay. However, this causes a loss in other features such as VRR, 120 Hz and more due to the soundbar not supporting all HDMI 2.1 features. Thus why I want to do the setup with the console connected directly to the TV, as should be intended.
Should be noted that there are multiple threads online about this issue taking place with both this TV, this soundbar, as well as other combinations of TVs and sound systems, so it doesn't seem to be an issue exclusive to this new TV.
neon sapphire