Yes, any ‘bonded speakers’ are connected to their Sonos speaker they are bonded to. In your case, that would be the Arc. They get IP addresses from the router via the proxy through the Arc, but ignore your WiFi (or the lack thereof) and get their signal from a hidden 5Ghz channel created by the Arc. This is why you should never turn off the ‘radio/wifi’ on a Sonos soundbar. The surrounds and Sub(s) are trying to connect to it. 

Should have hit refresh before replying, the above is good news.

The Arc will create a 5 GHz link to the Sub and Surrounds but as the 300s don’t do SonosNet I’m not sure of the 2.4 GHz networking.

Thank you so much. That’s really good news. It’s a new build extension, so I’m assuming you wouldn’t recommend getting an Ethernet wire over to the sub and Era300s as the 5ghz network created by the wired Arc will take care of everything right? 

Thank you so much. That’s really good news. It’s a new build extension, so I’m assuming you wouldn’t recommend getting an Ethernet wire over to the sub and Era300s as the 5ghz network created by the wired Arc will take care of everything right?

I wouldn’t. At least not to support those Sonos devices. You may want to pull Ethernet cable over there to support other devices at some point.

When I ran Ethernet cable in my home in CA, I ran several drops to every room, just for the future. Much easier to do when under construction, rather than afterwards like I did. 

I’m anal about wiring. In my opinion it would be prudent to run some fiber as a future hedge.

I’d agree. I wouldn’t run just Ethernet, but fiber, and potentially RG6, although that’s a lot less common, these days. But certainly several possibilities offered by most structured wiring systems. 

Hi @Aslaidlaw 

I’m late to this party.

I read your post and just want to clear things for my own edification...and may be yours .  You stated….

• WiFi in my home does not reach my Era300s or sub but my Arc is hard wired to Ethernet switch. Will Arc create a network and talk to Era300s and my sub gen 3 for home theatre 

One thing to know that some Sonos speakers (the Arc being one of them) creates the SonosNet which is a private 2.4Ghz frequency outside of the 2.4Ghz generated by your router. It allows for better connection for all Sonos speakers to join for better stability. However, the Sonos Move2, Roam, Era 100 and your Era 300 do not join the SonosNet. So, if you were thinking that wiring your Arc would improve WiFi for your Era 300’s then that will not be the case.

As others have stated the Arc creates its own 5Ghz channel to communicate with surrounds and sub. It does so because the 5Ghz frequency is fast and does not allow the low-end and surround data sent from the Arc to those speakers to fall behind. In short the 5Ghz frequency sent by the Arc and used by the sub and surrounds keeps everything in sync. 

You can test for lag by sending TV audio by from Arc when grouped to Sonos speakers not part of its home theater setup and you will hear a delay of 75ms to those speakers. That’s only true for TV audio. Music sent from the Arc when grouped to other Sonos speakers does not experience  a delay and vise versa.

If your Era 300’s are stand-alone speakers and d not show in the Sonos app as a room then you have a network issue that has nothing to do with the Arc. 

On the otherhand...if you were having difficulty with the Arc communicating to a sub and surrounds to which it is bonded; then there is something else afoot which may require running a diagnostic within 10 minutes of the communication failure, posting the reference ID in your next post and calling Sonos tech support to review the data.

Thanks everyone for all the great information and advice. I’ll be setting this up over the coming weeks and look forward to fantastic home cinema and awesome music.