Lost surround and sub ( after update ?)

14.8.1  D#18887051765

Here’s a little fuel for the fire. I haven’t had a dropout in about a week and decided to try and cause one to support the fault finding effort. For the last week I’ve only had my main Apple TV connected, no other sources. I’ve watched all kinds of content on multiple apps with no problems. In preparation, while watching content on Prime on my main Apple TV,  I connected my second (vpn) Apple TV and powered it on. Before switching over to it, I tested my favourite atmos test scene and observed my first dropout in a week. I did not even have to switch sources to cause the dropout, just connect the second device and have my TV recognize it. 

I restored sub and surround with the new disable/re-enable Wi-Fi trick on the arc and played a bunch of trailers on Prime and then auto play trailers on Netflix (still on second Apple TV). While on Netflix I had a second dropout. I unplugged and disconnected the second Apple TV and restored sub and surround again.

I connected and powered on the second Apple TV again to see if it would trigger another dropout immediately which it did not. I watched my show on Prime for a while then flipped around different content a bit (on main Apple TV). Then I watched trailers on Netflix and triggered a third dropout (all in the space of an hour). Super interestingly, after watching various content and then trailer hopping in Prime and Netflix, the second and third dropouts both occurred when viewing the same Netflix trailer (Venom) after watching maybe 10-12 other Netflix trailers.

I restored again and jumped straight to Venom but a fourth dropout did not occur (just a coincidence then?) I disconnected the second Apple TV and jumped around content a bit on the main Apple TV. I went through the same trailer hopping exercise and was not able to trigger a fourth dropout within a similar timeframe. I won’t do a full disconnect/reconnect and power cycle of all devices and see how long I go before another dropout.

I’ve had a case open with Sonos support for a while and now that I think I can force a dropout, I’ll try to get escalated as high as I can to demonstrate it.

Takeaways: My system is far less stable with 2 Apple TV’s connected. My system might be completely stable with just 1 Apple TV connected. There appears to be more to it than just codec changes. It seems to be HDMI source related. Perhaps a codec or format change can appear like a source change (or source renewal?) depending on how certain devices handle format changes. This might explain why some people’s systems are more stable than others. 

@Freddy45764 remind me what tv you have? Thank you all the testing btw

im inclined to believe it is something related to HDMI CEC

LG C1 OLED. CEC seems very plausible to me at this point. I also bought a CEC blocking HDMI adapter but haven’t tried it yet. I’ll try to connect the second Apple TV again with it and see if I get the same problems. 

What really makes me think it’s CEC related is that I think the Apple TV is really stubborn about CEC so that even if you turn off “control TVs and receivers” it doesn’t actually completely disable CEC

on my LG CX system which doesn’t have an Apple TV my only sources are game consoles I have CEC turned off on all of the devices and I’m confident they actually respect it being disabled. 

as I mentioned I ordered a CEC blocking adapter that should arrive tomorrow so I’ll test further 
 

Ya that all seems to track for me. I have it off on my second Apple TV and on for my main FYI. But I agree, I don’t think that setting is doing the job. 

@Freddy45764 @peterbault - that is quite an interesting thread that I missed whilst sleeping! I also have two Apple TV’s in my home. Both connected to the network (not via any VPN though). I have had these in my house for years without problem.

In terms of my case, Sonos have now exhausted testing and I have been told this is going to L3 Engineers for further investigation.

Last night, I did catch (and send a diagnostic) on some new behaviour. My rears and subs stopped when I flicked to Godzilla movie on Netflix via AppleTV. I left it playing whilst writing an update to Sonos and sending diag details. When I got back after 10-15 minutes the surrounds and one sub returned! (I sent another diag to capture that as well).

This is a very challenging problem to understand.

To be clear, the purpose for my second Apple TV is to connect through vpn. All the testing last night was done with the vpn router powered off and the Apple TV connected to main network via wifi. VPN is certainly not part of this as it has been unplugged for 3 weeks

@Freddy45764 @peterbault + All.

Its question time! (Sorry, no prizes).

1. What exact version of the Apple TV do you have?  (i.e. 4K Gen 1 or Gen2?)
2. What HDMI versions does your TV support? (i.e. HDMI2.0a or HDMI 2.1)
3. Do you have CEC turned on for all appliances? (i.e. TV, Apple TV and Sonos)