Hi.  Sonos HT systems are designed to communicate within the HT setup using direct routing using their 5GHz radios.  You might regard it as a form of 5GHz SonosNet but it doesn’t really matter what we call it.

Each Sonos speaker has a setting for ‘enable / disable WiFi’, which i assume is what you refer to in your post.  This is very poorly labelled, as it in fact enables and disables the wireless radio on the speaker, making the speaker incapable of any wireless communication when this setting is set to ‘Disable’.

So your post made sense to me until the bit saying that with cables disconnected and the radios turned off, the rear speakers continued to function.  Are you sure?  My only guess is a cache working its way through.  Can you confirm please?

Hi John, thanks for your quick reaction, appreciate it.

So you say that if I disable the Wifi setting through the controller app there could be no wireless communication at all on that speaker.

I did hear the surrounds after disconnecting the ethernet cables. However it could have been the cache - delayed signal. I will check it today again. 

So in fact when all speakers (Arc, surrounds, Woofer) are connected through ethernet cables and all settings for wifi are disabled on the app, it will be a 100% wireless setup? 

Yes.  As I mentioned, the HT system is designed to work wirelessly using direct routing, but I think if you go fully 100% wired and turn off all the radios it will work without wireless. 

Your mobile controllers will still be talking wirelessly to your router (although I believe ethernet adapters do exist).

Try those surrounds again  - I’d be interested to hear what happens.