I have my Xbox One X connected via HDMI to a Phillips 50PUS7304/12 TV, which is connected via optical audio to a Sonos Playbase. I want to keep the main audio to the Sonos from my TV for the movie apps on it like Netflix, Amazon Prime Video etc..
I don’t experience any audio lag when watching anything directly from my TV.
If the Xbox audio output over the HDMI is set to stereo uncompressed it's absolutely fine, except that I want better than stereo. It won't accept being set to 5.1 or 7.1 uncompressed (for this I'm just assuming it's because the TV isn't really made to be a high-end audio receiver which is fair). If I set it to bitstream out, the Dolby DTS setting is accepted but no sound comes out (presumably because Sonos don’t support it), while the Dolby Digital and Dolby Atmos settings both have a noticeable lag (maybe up to a second).
I have exactly the same issues when using the optical output directly from the Xbox to the Playbase, the only difference being that Atmos isn’t an option.
If within the bitstream settings I set the Xbox to “allow the audio receiver to decode blu-ray audio”, this lag disappears when playing blu-rays. However, it still exists for doing anything else on the Xbox. Why is this and what can I do to fix it?