I wanted to run a situation by you all. We have a customer that has an RTI XP6 processor, couple T2i remotes, and (2) RTI PCM4 units - 1 for Master Bedroom and 1 for BBQ area. That is the control system. Then we have 6 or so Sonos Amps in place, all setup via WiFi, none are hardwired. For the network we are using a Luxul Router and Luxul WiFi APs. The customer is experiencing huge delays when trying to use the T2i remote in the Master Bedroom. When he pushes a button it takes anywhere from 5-13 seconds for the button press to respond. It is happening across all sources in the Master Bedroom - DirecTV, AppleTV4K, Samsung BDP. Again, the Master Bedroom is controlled over 1 of the RTI PCM4 devices. If the XP6 processor gets power-cycled, the issue goes away for awhile before coming back again. I called RTI and they suggested putting in a managed switch and applying settings to deal with the Sonos Spanning Tree issues and Multicast devices issues because RTI says that the PCM4 devices are very very dumb network devices and the its cache could be being maxed out quickly from all the multicast traffic from Sonos. Have any of you come across anything like this? Or do any of you have any ideas as to what may be going on? The remotes, the XP6 processor, and all the Luxul products all have current firmware updates applied.

Too many Sonos device to be using Wi-Fi

Listen to what they told you about a managed switch and spanning tree. A Luxul managed switch should have spanning tree on by default - I think.

STP is a potential issue for wired Sonos devices. I agree, with that many devices, you should be wiring one or more Sonos devices. Make sure that Sonos uses a different channel than the WiFi. If all of the Sonos devices are in one area, wire them to a switch, rather than daisy chain.

If your Sonos amps are all in one location, wire one only, and let the others all talk to each other. No STP problems will result.