Multichannel PCM 5.1 dropping out since 14.10 update

@RANDUSR23296 has done more than Sonos ever did (w/c is actually nothing). Sad that they can’t even be bothered to lift a finger despite all the evidence shared here by the users.

 To recap, Sonos’ response to this situation after ~1 year and ~400 posts:

1. No technical investigation that cleared the Beam of any fault
2. Place the blame on LG because numerous unrelated results come out when you google for “LG OLED 5.1 issue”
3. Claim that LG will fix it with source being “trust me bro”
4. Refuse to elaborate further. Leave

@ste_ms tagged the mod on a post from a week ago and they have not yet responded. Considering that monitoring this place is literally their job, unless they are on holiday, it is clear that Sonos had already  ducked and ran.

To potential buyers or those within the return period: if you’ve come across this thread, take heed and stay away from Sonos.

I think an internal investigation could have happened (rather than just auto-timing out their Jira ticket after 12 months). It's easy enough to reproduce, should be easy to spot in a lab with industry test gear, but Sonos may now have chosen not to publicise the results based on their discoveries.

If it turned out that only a hardware modification could restore stability then I can imagine any company involved  being much more cautious about admitting a fault/offering a fix, maybe hoping that another stake holder would back down first. The RMA costs would be considerable, so too would the reputational impact of shipping a hardware fault. 

It's rather ambiguous from Sonos’ response whether they have actually been talking to LG or not before deciding to walk away. There does seem to be evidence of LG trying to mitigate the problem, by at least stabilising HDMI1, but again they could be limited by hardware at this point. I only search for English language forums, there could be LG discussions going on outside my language bubble. Sonos are tiny (by market cap.) compared to LG so may just have the same communication issue with LG that their consumers do. LG have the upper hand here as there's still no evidence offered on this thread of any other eARC device than Beam2 triggering the TV to drop PCM5.1 over eARC.

Seems to me a change from either company would resolve the issue sufficiently. It's a poor response from Sonos whatever the situation:

- they know the cause and won't fix

- they don't know yet so can't fix

- don't want to know and have done nothing for 12 months.

Edit: to be fair, it is also possible that Sonos have investigated and their conclusions are covered by some kind of NDA...

Just to give an update, the dropouts came back, not sure if there was another Tv or sonos update since my last post. I’m just using ps5 with 7.1 and seems pretty good so far with miles morales. Was curious if there was any xbox users here as I have’nt seen any mention for settings working with series x. Need to hook mine up and see what the options are. 

Also curious as an experiment, since hdmi slot 1 seems to work (have been playing zelda totk without issue this way) if using an HDMI switcher might help? Most of the switchers are 4k and 60hz, which would potentially cap framerate depending on the console/display. 

Why buy a switch when you can buy a one way optical HDMI cable to fix it? See my posts a few pages back about this workaround if you haven’t seen it. 

I guess a switch would be operating all signals as intented, whereas blocking the Beam2 video by whatever means could be interpreted as out of spec for Warranty purposes.

Maybe this sort of thing would be sufficient:

https://amzn.eu/d/feSCeXi

My experiences with switches involving  HDMI though are that they either miss some vital capability or are annoyingly slow.

5.1 PCM started to work fine with PS5 and LG CX 3 days ago. It worked perfectly for two days, 3-4 hours of gameplay each day and no cutouts at all, until I had to cut power from all three devices, and now the issue is back again. I wonder what did I do to make it work for 2 days?

EDIT: I just read this thread a bit more and realized that the same happened to a lot of people before, but then the issue came back again. Sigh...

Thanks for taking the time to post the new data point. It seems that LG C3 chipset isn't drastically different to C1/C2.

Indeed, power cycling the Beam2 should re-instate the dropouts immediately.

Sorry, maybe I was unclear. I have an LG CX, not a C3. 

Ah, got it. Sorry, I misread your post. It was @Retcon with the C3, I should have scrolled up to double check before replying.

Anybody seeing a change on 15.5?