Today I received my new Sonos Arc, and I was going crazy because I couldn’t add it to my existing Sonos network. The app would see the new device, but when I pressed the button on the back nothing happened. I began to wonder if the new Arc was just defective, but it is not.

I have a Ubiquiti Unifi wifi network with a whole bunch of wireless APs, and in order to optimize wifi performance I have had to enable an option in the Unifi controller that blocks LAN to WLAN broadcast and multicast activity. If you have a lot of devices using mdns, especially Apple devices, then you may have much more wifi bandwidth consumed by broadcast and multicast activity than you realize, and it can be really slow!

Anyway, on a hunch I turned off the “Enable Multicast and Broadcast Filtering - Block LAN to WLAN Multicast and Broadcast Data” option in the Wifi Networks section of the Unifi controller, and then I was able to add the new Sonos Arc immediately. After the Arc was added I turned the option back on, and the Sonos network continues to run like a champ. It seems only to affect the step when you press the button on the back of the device while adding.

I hope this saves some other Unifi user some frustration.