Only one Sonos speaker needs to be connected to the router with an ethernet cable to create SonosNet. So connecting the second Arc is not necessary.
Thanks, that’s what I thought, but it’s good to have a definitive, crisp opinion. One more benefit of Sonos ownership is a very responsive community.
“required, redundant or harmful?”
You usually can connect as many Sonos as you like to Ethernet, it does lower the amount of data that needs moved over the radios. In some cases you’ll see network glitches when you connect multiple Sonos, usually easily solved following instructions here on STP, Spanning Tree Protocol tweaking.
I’m in a busy RF location so I wire all the Sonos here that are easy to wire, giving lower RF usage and more places for the wireless Sonos to connect to. Not really needed in most cases but since it was easy and only cost me a short Ethernet patch cable I did it.
Thanks! For now I’ll take the easiest approach and just leave the wire in place for the downstairs Arc, and I assume the upstairs Arc will join the (wifi) party, along with any sub/surround speakers I might add to it later.