Issues with the sound sync

That’s certainly odd. It suggests that the TV isn’t handling format changes properly, and consequently munging the feed to Sonos, which merely plays what it is handed.

I would try several things. First, reboot the TV, and all devices that are feeding it via HDMI. I’d also reboot the Sonos. Unplug them all from the wall for two minutes, then plug them back in.

Then I’d check each device for updates to their respective OS. It’s possible this issue is ‘fixed’ by either the reload of the device, or a new OS completely.

However, if it continues to randomly occur, the next time it happens, I would recommend that you submit a system diagnostic within 10 minutes, and call Sonos Support to discuss it. Don’t post the resulting diagnostic number here, their lawyers get sensitive about GDPR.

There may be information included in the diagnostic that will help Sonos pinpoint the issue and help you find a solution.

When you speak directly to the Support staff, they have tools at their disposal that will allow them to give you advice specific to your network and Sonos system.

Thanks for the information. I have tried all your suggestions already without any progress and all my devices are up to date. I will try the system diagnostic process next time. 

I have recently been in contact with the support and they just suggested me to change the “digital output” of the TV to PCM instead of Auto but the problem will remain and with the setting set to PCM the volume decrease a lot. 

I believe I have tried every possible setting both on TV and the Arc Ultra but the sound synchronisation issues on Swedish TV4 remains.

On TV:

eARC output connected to the Arc Ultra

HDMI-eARC set from auto to off (Maybe a bit less issues with the settings set to off)

Digital Output format auto to PCM (Lower volume with the settings set to PCM but still issues with lip sync. 

On Arc Ultra:

Lip-sync set to zero since higher setting will make the problem worse.

This must have something to do with the handshake between the TV and Arc Ultra since this issue doesn’t appear if I disconnect the Arc Ultra from the TV.

It seems odd. Sonos doesn’t ‘know’ that the signal from Swedish TV4 is any different than any other channel…I would suspect that there’s a difference in what your service provider, whomever they are, are sending to you. The TV just doesn’t include the channel information in the stream it sends to the Arc or the Arc Ultra…or frankly, any ARC stream via CEC. And I suspect the difference you’re ‘hearing’ when you disable the Arc Ultra and use the speakers on the TV is due to a stereo signal being played on the TV, as opposed to a 5.1 signal of some type being played on the Sonos. Two different audio streams. 

Let me clear up my first statement, it is a little ambiguous. Sonos doesn’t get any ‘this is X channel’ in the audio stream. It does receive data about what kind of stream it is, so it can properly decode it. But it has no knowledge that the data is from Swedish TV4, only that it is X type of data. 

Is this an issue only on Swedish TV4?

This occurs only on Swedish TV4 as far as I have noticed. At the moment I am trying to stream TV directly through the web browser instead of using the Telenor App and it looks like it works properly that way. Maybe the problem is within the streaming app. I have been in contact with the Internet/TV provider several times before without any progress but I believe I have to contact them again.

The movie industry resolved voice sync by the early 1940’s. The video industry is still struggling with this. Everyone’s attitude seems to be “it’s not my fault”. I do notice that movie channels have fewer voice sync issues.