Multichannel PCM 5.1 dropping out since 14.10 update

Mine has come back too, however I redid the steps you left here last time but I set it as home theatre instead of soundbar and it appears to be working again. Fingers crossed🤞 
 

edit: turned my tv off and when it came back on the issue came back

Sounds like it’s an issue in the TV set somewhere. Sonos plays whatever it’s handed. 

Have you contacted the CS for the manufacturer of the TV set?

I can chip in with my experience regarding this issue. I bought a Beam Gen 2 a cople of weeks ago and had the exact same problem. Sound dropouts 1 sec every minute or so when playning Xbox Series X with uncompressed 5.1. Uncompressed 7.1, Dolby Digital and Dolby Atmos worked fine.

I have a LG C1 65” with ultra certified hdmi cable connected between the TV and the Soundbar, Xboxs own HDMI cable connected to the TV. Both the TV and the Beam with the latest firmware. I couldn't figure out what the problem was. I tried everything that I could think of, factory reset, changed cables, diffrent setting on the TV and the Xbox but nothing.

In the end I returned the Beam and bought an Sonos Arc instead and now everything works just fine. No problem with uncompressed 5.1 and I’m using the same settings on the TV/Xbox and the same cables I used for the Beam.

I didn't read the whole thread but It seems a lot of you have an LG TV (including me) so maybe there is a problem with LG and the Beam Gen 2.

i'm sorry I didn’t brought any solution to the table but I hope my input can be of some help for you guys to figure out what the issue can be.

Couldn't possibly be a Sonos bug, right? Despite the Beam 2 having internal audio buffers for lip sync, true play, multi-room, and having CEC control and HDMI handshakes and considerable DSP. Could be in the C1 too from the experiences posted, but let’s try to remain objective and keep the apologist rhetoric to the first page of these threads?

Edit: That being said I noticed there is a new LG C1 firmware released (03.33.26) which I have yet to install, will report back if this changes the behaviour of the dropouts

It’s never impossible to be a Sonos bug, by any stretch. Just unlikely. But if it were a Sonos bug, there’d likely be thousands upon thousands (relatively speaking) posts about it. 

Sonos is essentially a “dumb” device, at the end of a long chain of things. All it does is play what it’s handed, in whatever form it can, and reports back to the CEC computer on the TV a small amount of data (what type of device it is, what formats it can play, and volume info, as near as I can tell). Sure, it has those things you mention, but if they work elsewhere (for instance, on my TVs, and most other folks installations), then they should work essentially the same everywhere. 

More often than not, the issue tends to be upstream. More so before CEC became a standard, since optical, used on the PLAYBAR and PLAYBASE, was a one way transmission, but still. There’s just not that much going on in the Sonos products. 

Which is why, in the preponderance of posts I make (check me on that, look at many of my posts), I do suggest a diagnostic and a call to Sonos. Just to be sure if it is a Sonos issue, and if it is indeed a Sonos issue, providing the engineering team hard data to look at. All of the engineers I’ve worked with in the last 40 years have wanted hard data, not anecdotal data, otherwise they return quickly with a “it works on my machine” response. 

There have been calls to support and diagnostics sent in the thread. We have all reset TVs and Beam, changed cables, settings... As far as I know there is no clear answer as to what the problem is or if it is at Sonos or LG side. 

There are multiple posts here and in Reddit about this issue but there is never going to be thousands because it requires a quite specific combination of hardware and settings: Beam + LG CX and above + LPCM Multichannel 5.1 output. It is even possible that many people that have the issue just changed to Dolby if allowed by the affected device to solve it... But this is just a workaround and not always possible...

Edit

My experience is similar to many others here. My Setup LG CX (04.40.20 latest update), Sonos Beam Gen 2 (Version 14.19 latest update) with 2 IKEA SYMFONISK bookshelf speakers, PS5 & Series X. Beam is hooked up to Ethernet, 2 Ikea Speakers are on gigabit Wi-fi (router is in the room). I am using EARC, Bitstream, Digital Sound Out is Pass Through. I have 48GB Certified Ultra HDMI Cables from Monoprice. When set to Linear PCM, AV Amplifier 5.1 on PS5 I see Multichannel PCM 5.1 on the Sonos App. Dropouts occur somewhere in the 2 minute range. When set to Uncompressed 5.1 on Xbox I get the same dropouts. No issues with 7.1 on either console. Now if I set the TV to Digital Sound Out Auto instead of Pass Through and change the PS5 to Dolby, I get Dolby Multichannel PCM 5.1 with no dropouts. I guess the question is then, whats best? Multichannel PCM 7.1 and hope the Sonos Beam downmixes correctly or set it to Dolby Multichannel PCM 5.1 on both the PS5 and Series X? Non Dolby Multichannel PCM 5.1 skips on my PS5, Series X.

Just to follow up I found out setting it to auto and having “Dolby Multichannel PCM 5.1” has definite audio delay. So sounds like Non Dolby Multichannel PCM 7.1 is the way to go until this is fixed, if ever. Just sucks knowing a 7.1 signal is being sent to a 5.1 device.

If you leave the TV on pass through but set the PS5 to Dolby do you still get delay? There are a number of other discussion threads around that say that fixes the delay issue with Dolby output - on auto there is a re-encoding of the audio causing the delay I think.