Does this also happen when you only use ARC? Do you really need eARC - at this time you do not need eARC for sound if you do not use external players.

I have a Shield connected so do need eARC for Atmos etc.

Hi @loobar23 

Thanks for your post!

There doesn’t seem to be any issues reported in the diagnostic - the relevant logs look no different than if you were just changing channels.

I recommend checking the TV for software updates, and also unplugging it from power for a couple of minutes.

I hope this helps.

Hi Corry P. I’ve been in contact with Sonos support and they assure that there is a problem with audio received from the TV unit. At present I am in quandry, is it the TV or is the Arc. Have tried with a Beam, and no issues, so suspect the Arc maybe the issue.

Sonos support wish to go through all the checks again but I think I’ve proved a point (at least to myself).

Hi @loobar23 

Given that the issue only happens when watching received TV channels - please let me know if that is no longer the case - you cannot discount even the weather. I would assume that CEC issues would be repeated despite the model connected to the TV - perhaps switching back to the Arc would now find no issues with it either? In addition, our handling of your case went a bit wayward at the end there - apologies. Therefore, I have arranged for a more senior technician to look over your existing case and you should hear from someone in the next day or two.

Hi Corry, the conclusion of the senior tech is that the fault is with the TV, no suprise there. And the conclusion of Panasonic is that the fault is with the Sonos Arc. And no suprise there either.

Unfortunately there is no stock to swap the TV, so would have to go back. for a refund, which is unfortunate as the picture quality is excellent.

The issue only ocurrs with  live FreeView TV, and the inbuild apps. No issue for attached devices such as Fire or Shield. I want to use the inbuilt iPlayer app as BBC have released UHD content, so it makes sense to use that as the pic quality is excellent.

It does not seem to have the issue on the satellite reception, but the TV lacks Freesat EPG so is not a great solution.

Hi @loobar23 

That certainly sounds frustrating! I can only say that the Arc would have no idea where the source of the audio is, so wouldn’t know how to only misbehave for the in-built apps and TV reception - it does sound like the TV is at fault. Was your Panasonic support case escalated to a higher level too?

Been there - I had a TV that broke the day before the warranty ran out. A close call, but Amazon had no spares to replace it with and I ended up buying another brand from a store immediately. I ended up hating the TV I got for years - don’t make the same error I did! Choose just as carefully as you did last time.

I don’t see why your nVidia Shield wouldn’t be able to play UHD on iPlayer. With AI-upscaling enabled, you might not even need more than standard HD to get the same perceived quality, saving you some bandwidth. I too have a Shield, but am avoiding BBC services so that I don’t actually require a TV license, so I am unable to test this for you. It just occurred to me that I don’t have a 4K TV either.

Did the Sonos Engineer get you to disconnect all ‘other’ TV HDMI-connected devices (Shield/Cable box etc?) to eliminate it was not those devices attempting to steal the CEC focus away from the TV/eARC connection?

If that’s not been tried, I would perhaps give that a go, particularly as the issues reported are intermittent, which is a classic sign for that type of problem - it is easy to solve too.

After removing all other connected devices, I would also power off the TV and Arc at the wall for 3 minutes, before testing, as that will resolve any HDMI handshake issues. See if the TV inbuilt Apps then work without issue.

Ken, thanks for the info. I have indeed done that, though I did not unplug the TV and Sonos after doing so. So I might as well try that. Its frustrating to test, as it could require the TV to be on for one hour before doing it.

On iPlayer UHD, it seems only certain devices have this working, and mostly are TV manufacturers. There is no UHD on iPlayer on the Shield - for eg Wimbledon was in UHD on the Panasonic but not Shield or Fire.

Shame I have no one near by with an Arc, so that I can rule it in or out.

Hi @loobar23 

I had no idea it made a difference - it seems a bit strange, seeing as the BBC don’t make TVs or other devices to be considered first-party. The AI-upscaling on the Shield should be able to take a HD feed and make it look like a UHD feed, however - it should simply be a case of enabling the setting on the Shield.

Slightly wrong - the Firestick 4K Max supports UHD on iPlayer.

The iPlayer UHD supported devices are listed here:

https://www.bbc.co.uk/iplayer/help/questions/supported-devices/uhd-supported-devices

I understand their UHD trials have been ongoing (on/off) since 2016. My LG TV is supported, but I’m somewhat surprised it’s not available on either the Amazon 4K Stick, or the Nvidia Shield?

Yes indeed, its bizarre. I have a Shield, Firestick 4K and 4 Max. The max has UHD programs available, the others do not. The iPlayer app on the Panasonic TV also has UHD available.

so I removed anything from HDMI 1 & 3, namely a Shield and a Firestick. No outage issues last night, though did not have the TV on for hours, but it was on for at least 90 mins on a mixture of live TV via Freeview and iPlayer.

Later when messing around with the native Plex TV app (only every use Plex via Shield or Fire) the Arc lost connectivity altogether. I think that might be a red herring; the app was struggling to play any 1080p or 4K movies, and I won’t use the native Plex app as it is nowhere near as good as the Shield for eg. Just seemed an odd occurance. Rebooted TV and nada, but removing and re-inserting the Arc HDMI cable re-engaged the sound via the Arc.

Rather than keep rebooting the TV/Arc, perhaps try toggling off/on the "TV Autoplay" option instead in the Arc Room Settings in the Sonos App, or perhaps see if the TV icon at the bottom of the Music Services Tab (music icon) brings back the TV audio,  or look to the TV settings instead and try toggling the TV Digital Sound Out audio between ‘Passthrough’ or ‘PCM’ and ‘Auto’ and maybe leave it on passthrough if the TV has that option. See if those things bring back the audio rather than having to reboot everything.

Also the fact the native Plex App is struggling to play, doesn’t sound right either, like there is a network related issue… is the TV wired to the LAN or using a wireless connection?

I use Plex on my LG TV and that App seems fine to me, at least on par with what’s on the Shield and I use multiple Plex servers here. 

So my thoughts are if using a WiFi connection maybe just check the router settings and if necessary, put the 2.4Ghz Band on a fixed non-overlapping channel such as 1, 6 or 11 and if the router allows set the channel-width to 20 MHz only and try that with the TV… or cable the TV to the LAN if practicable, or check it’s cable if already wired.

OK...worked it out. The Panasonic Plex app doesn’t like .265 video format. Trust me to pick only those to test last night. Works fine with .264.

I did just check my own plex servers here and I did notice there was a server update. (for my Linux server) so that maybe worth a quick check too, perhaps?

Anyhow if the intermittent audio interruption issues do go away, I would then add the (HDMI connected) devices back to the TV over the next few days, just one at a time and see if any devices in particular perhaps causes the issue and (if possible) switch off CEC on that one device only (remember to power off everything when you do make that change and disable its CEC feature) and try to perhaps identify the problem device and just leave CEC, on that problem product, disabled.

Hope that you do manage to find the answer to this, going forward.

Plex is up to date, am running from a Synology NAS. Just had a look online, the Panny Plex app does seem a bit naff - plenty of people saying its not working with .265. As I say, I will only use the Shield for Plex though, so to send through Dolby TrueHD without any issues etc.

So after removing all devices from the HDMI ports the problem persists. Same ten second outage when watching live TV or using an onboard app. Frustrating. 

Sorry to hear that you’re still having issues with this.

I assume you’ve already tried a different HDMI 1.4+ (heac supported) cable between the Arc and TV, in which case, it sounds like there is possibly a fault then, with either the TV, or the Arc.

I’m also assuming you’re using the latest firmware updates on both the Arc & TV aswell?

Maybe go back to the support desks for both Sonos & Panasonic and see if they can assist you further - or if you have another TV in the Home, you could try the Arc with that TV too perhaps?