No, although I don’t think it’s terribly well delineated anywhere. Much like your old sound bar, the Sonos will use a ‘hidden’ 5Ghz network channel to connect the signal coming from the Arc going to both the surrounds and the Sub. You don’t have any control over that channel, it automatically is selected for you. 

As to the connection between your Arc and your router, you can choose to either connect via a wired connection, SonosNet, or directly to your 2.4Ghz channel that your router is using (channels 1, or 6, or 11, since they don’t overlap).

There’s essentially zero connection between those two concepts. The Arc will want to connect on an unseen network with its ‘satellites’, whether or not you have the Arc wired or not. which is why the ‘radio/WiFi’ needs to be left on at all times, whether it’s wired or not. 
 

Note that there is a secondary method of connecting both surrounds and subs to your router by cabling,  likely for installs that are super rich interference environments, so the radio/Wi-Fi can actually be turned off, but I tend not to recommend that, as it feels like a fall back. Some Sonos engineer is probably cursing me now for all the work they put in to that feature.

If you’re going with the Arc, I’d suggest using the ‘normal’ connection, and only fall back if you find significant disconnects. One of the issues that many people run into are networking issues, not Wi-Fi issues, but they don’t understand the difference. There are some routers that just don’t handle the DHCP table as well I would like, and the nature of all Sonos devices asking for new IP addresses every time they reboot for new software makes lots of people think Sonos is at fault, so if you have the opportunity, reserving IP addresses, while not required per we, is a good idea.

I’m sure you’ve read about all of the prior issues with ASUS and Sonos in the past, they’re not held in high regard, at least by me, but I do think it’s been a couple of years since the last major software release for the routers that were an issue. 

This diagram seems to be disagreeing with your interpretation of not using SonosNet.  Looks like it will use my WiFI network if I disable SonosNet.

https://support.sonos.com/en-us/article/choose-between-a-wireless-and-wired-sonos-setup?language=en_US

If by wired to the sub and rears you mean Ethernet, I have no issue with that. The house is fully networked, 

As for ASUS, I am not using their canned off the shelf mesh system. I use two RT-AX86U routers in AIMesh mode. These are running the Merlin-Asus optimized OS. Front haul and back haul are Ethernet thru a managed switch.  

What Bruce mentions is correct in his post. The Sonos Support link you’re referring to in your second post @TNPAPA is showing the differences between a wireless and wired (SonosNet) connection relating to different Sonos ‘Rooms’, whereas Bruce is just referring to the ‘bonded’ connection between the Sonos Arc (Soundbar) and its Surrounds/Sub… that bonded setup occurs within just one Sonos Room tied together (usually) by an ad-hoc 5Ghz wireless signal, which auto-seeks the best 5Ghz channel to use.

It’s a 20Mhz channel-width only signal and operates within normal WiFi range for the 5Ghz band and it will even use DFS channels too. If you do encounter any interference (unlikely), then my suggestion would be to simply reboot the soundbar and just let it re-negotiate the wireless connection again, but it should do that automatically anyway. I personally would never wire the surrounds, or the sub, to the local LAN.

For the record: I’m anal about wired network. Since there is a history of 5GHz interference at this location, I recommend wiring as many SONOS units as is practical.

I always wire where possible, but sometimes you gotta go wifi.  That said my main concern is the interference to the sub and surrounds.  The Samsung HW-Q90R system I currently have is LOCKED to one channel that can't be changed. My immediate next-door neighbor is locked to the same channel on his AT&T controlled Fiber Modem/Router, and it can't be changed.

In looking for a new system I saw reports of the same interference issue with LG, Vizio and many other soundbar based surround systems.  I just don't want to drop $2K on the Sonos and have the same issue.

This is what the spectrum in my house looks like.  As long as the SONOS can find a channel I am hopeful.

 

The answer is to perhaps try these things. If you buy direct from Sonos they do offer a 100 day money back guarantee. I think the period may vary by Country so it maybe best to look at the T&C’s. See this link:

https://www.sonos.com/en/legal/terms#2022-legal-terms-sale-returns

I’m reading that plugging the sub into the ethernet network has no effect, it will still use SonosNet to communicate. True?

Again, bonded is not the same thing as SonosNet. Two different systems..,as near as I can tell. The Sub is always bonded to another ‘parent’ device, which means it communicates on a 5 GHz signal where it can. You have no control over that channel, the Sonos system looks for the best available. I don’t know how frequently it does that, though, whether it’s periodic, or a one time thing.

SonosNet is essentially 2.4Ghz b/g/n. Bonding is on a 5Ghz channel. 

The idea is that Sonos doesn’t want to expose this data to the consumer, as in 99% of the users, it would be confusing, and contrary to the whole ‘easy to use’ thing that they are relying on.

Well when the gear arrives will be the test, will the sub stay connected or not?  It happens immediately with the Samsung, the moment my neighbor starts to send any data on his network I get a burst of digital noise and then the speakers disconnect, reconnect, disconnect. Imagine listening to a really sound intense movie and the speakers keep cutting out every few seconds.

The HT master continuously monitors, and will change channel if required. The HT master simultaneously instructs the satellites, so channel switching is very rapid. Audio should not be interrupted.