After a LOT of digging I think the issue have been located.
The volume syncing issue almost always comes from issues with the WiFi.
I had the same problem after switching ISP and got a new router.
So I tried a ton of different solutions but have found a solution that I think will work for most.
Here are the things you have to do in this order:
1)
Go to your iPhone settings and reset network settings.
Settings > General > Transfer or reset iPhone > Reset > Reset network settings
2)
Reset your HomePods and your Apple TV
Leave them not set up yet.
3)
Reset your router to factory settings and create a WiFi network with a new name.
Preferably disable the WiFi 5G mode. But you can try leaving it enabled and see if it works.
4)
Connect your iPhone to the new WiFi you created.
5)
Set up your Apple TV. Completing the set up with your iPhone.
6)
Set up both HomePods and leave them as individual HomePods for now and not used as TV output.
7)
When they are set up. Pair them as a stereo pair and set them as default TV output.
8)
If the problem with HomePods volume syncing continues, the problem is most likely your router.
Get a new one and use that to create a WiFi.
I ended up using an old Apple AirPort Extreme. Works perfectly.
Hope this helps if you have problems.
Very much appreciate the well detailed post and instructions. Don’t take what I’m about to say the wrong way. This is strictly a rant against Apple.
This is not a Wi-Fi or router issue. This is a HomePod issue. They suck as Home Hubs too. When all your devices are working fine on Wi-Fi except for one common device, it’s not the Wi-Fi. I perform speed tests right next to the HomePods while connected to the same node and everything looks good. I got two in stereo connected to an AppleTV staring at a hardwired eero node from 12-15’ away, line of sight and connected to that node. Still have this issue the OP describes.
HomePods are supposed to be an average consumer product that are supposed to just work without performing some crazy dance to the devil. It’s on Apple to make sure of that through software. How many times are we going to have to dance like this? It’s seemingly after every other update.
I’ve been using HomePods since they came out in 2018. I can probably count on one hand how many times an update just worked as advertised. These have been infested with bugs since day 1. Some, including myself, are very hesitant to even install an update.
Many of us have a very extensive HomeKit setup and setting up a new network will destroy that. It’s a nightmare. Now if only Apple could figure a way to let us do a HomeKit backup so we can fix the messes they create 🤔. A feature that’s been asked for, for quite some time but I digress. (yes, I know Controller for HomeKit has that but I tried it and it’s not very reliable).
This issue popped up for everyone after the latest update to 16.6. That’s the common denominator.
Once again, really appreciate you taking the time to figure it all out and to post this solution but it shouldn’t have to be this way. I’m not $hitting on you at all so please don’t take it that way for one minute. My beef is with Apple and their incompetent summer internship HomePod software team.
