Arc Ultra Surrounds Disconnect Daily After Extended TV Off Period

​@ScottDDev 

There are questions I have yet to get answered. If you did and I missed your reply … my apologies.

Questions:

Do you have different SSID’s for your 2.4Ghz and 5Ghz bands?

Do you have a Guest Network active?

My system has been stable for a few days now, so I wanted to share an update in case it helps others.

After restoring default settings on my ASUS RT-AX88U, I made the following changes:

2.4 GHz Band

• Disabled 802.11ax / WiFi 6 mode
• Set Channel bandwidth to 20 MHz
• Set Control Channel to 11
• Disabled Roaming assistant
• Disabled Explicit Beamforming
• Disabled Universal Beamforming

5 GHz Band

• Set Control Channel to 48 (non-DFS)
• Disabled Roaming assistant
• Disabled Universal Beamforming

After these changes, the Sonos Arc Ultra and surrounds have remained stable with no more auth/assoc/deauth loops.

The last changes I made before things stabilized were disabling beamforming and setting the 5 GHz control channel to 48, so one (or both) of those appears to have made the difference. I haven’t isolated which one yet.

ASUS is still looking into it, but so far this configuration has been stable.

ASUS got back to me:

…Your changes:

Disabling Roaming Assistant
Disabling Universal Beamforming
Fixing the 5 GHz channel to a non-DFS channel (e.g., channel 48)

are all aligned with best practices for improving stability in environments where devices rely on consistent, low-latency peer connections rather than dynamic roaming behavior.

At this time:

This does not indicate a hardware fault with your ASUS router.
It is also not unexpected behavior, given how advanced wireless optimization features can interact with proprietary device communication protocols.
The configuration you applied is appropriate for ensuring stable operation of your Sonos system.

For ongoing reliability, we recommend:

Continuing to use a fixed non-DFS 5 GHz channel (36–48 range)
Keeping Roaming Assistant disabled for environments with stationary IoT or audio systems
Avoiding features that dynamically steer or modify client associations when using mesh or multi-node setups with latency-sensitive devices…

If you avoid the DFS channels that leaves you 9 channels at 5 gHz but 165 can be iffy depending on your location.  

Channels 36, 40, 44, 48, 149, 153, 157, and 161 are all good first choices. 165 is a second but not DFS choice.

Good advice on DFS, avoiding it and the channels involved 52, 56, 60, 64, 100, 104, 108, 112, 116, 120, 124, 128, 132, 136, 140, and 144 is the safe bet. 

Some possibly bad advice, if the 9 non-DFS channels are crowded and you don't have a DFS priority user (usually radar) in your area you might be tempted. I was and picked channel 100, for no particular reason, and have been using it for a long time. I haven't had any DFS events where my Wi-Fi was shutdown or forced to change channels so I'm going to keep using it. If I'd have had any events I'd have tried other DFS channels or gone back to the safe ones.

Bottom line, go with the safe option but if you are willing to experiment with little or no support...