How to connect up via Ethernet with DoS2?

[ragwo]

@quartz78 Thank you for the thorough explanation. It's like I suspected, if I ever migrate to DOS2, I'll use ethernet all the way.

[MarkSolo]

After paired left and right in Stereo with WIfi With DOS2 , you can directly connect the Ethernet cable left to the right without router...

Good for a stereo pair... But when you plug Ethernet cable between Left and Right, you have to restart booth, and Ethernet cable will take priority over Wifi and CPL to communicate between speaker. Wifi to control the "stereo room", and the ethernet cable is used between left and right.

It's the best Stereo stable soluce.

Thanks this i can reach 60 ms of latency without problems. But with Wifi or CPL between left and right, 60 ms not work....

So streaming still relies on WiFi, it's only the synchronization of the two speakers that is controlled by ethernet? Isn't there a way to get rid of the need for WiFi all together?

It is the second or the third time I see people talking about the Ethernet cable directly between left and right speakers. Here's what I understood:

For setup and control:
1) you need a connection path from your MASTER speaker to your phone, to be controlled via Devialet app (or UPNP controller) => the apps won't work over LTE  

To get sound into the MASTER speaker:
2) if your source is in the local network (AirPlay source (including Spotify via AirPlay), UPnP), you obviously need a path from the MASTER speaker to your source device (phone, laptop, NAS).
3) Of course, in some cases, your local source (phone, laptop,...) is just a relay for an Internet source (think YouTube, Tidal etc.) - need a path from the local source to the origin source in the "cloud".
4) If your source is in Internet (Spotify Connect), the MASTER speaker needs an Internet connection
5) Finally, if your source is Bluetooth (including Spotify via Bluetooth), your Bluetooth device should be close to the MASTER speaker.
6) oh, and of course, physical inputs (optical and analog for Reactors) are wired  to the MASTER speaker

To distribute sound from MASTER to other speakers:
7) a path from master (left one, let us say) to the other speaker (right) - can be Devialet PLC, your home Wi-Fi, Ethernet via router, and apparently, direct Ethernet from left to right. Whenever the Ethernet cable is plugged (router or direct), it takes precedence (yes, remember to reboot, good point @ofrappier). Otherwise, the option from the app corresponding to the MASTER speaker is used (Auto, Forced PLC, Forced Wi-Fi).
8) now with DOS 2.10 and multi-room, the master obviously needs to get sound to all other speakers in all rooms...

To communicate between speakers (including synchronization):
9) also, paths from master to all others. It may or may not be the same as the (7)-(8), we'll never know. I guess one can find it out by using direct Ethernet connection between the two, metallic vault and independent power supply to remove Wi-Fi and PLC 

It pains me to think what happens to the music stream when I play YouTube via AirPlay on a stereo pair with forced Wi-Fi:
youtube.com -> router -> (http / wi-fi) -> phone -> ( Airplay / wi-fi) -> router -> ( Airplay / wi-fi) -> MASTER -> ( Devialet / wi-fi) -> router -> ( Devialet / wi-fi) -> right speaker
The first one is buffered, but the following four are not (or just a little), so any latency issue = risk of sound cut. I can see why @ragwo wants to avoid Wi-Fi

You need to see exactly where every data/control flow goes for your usage scenario(s) to optimize your setup. My advice:
- Only change the Auto setting to anything else if you already have issues.
- Do not count on the fact that MASTER is the left speaker, as reported in this forum. There is no guarantee that it stays constant and actually, for your optical right input, the MASTER is on the right! => if you try forcing Wi-Fi or PLC, do it on all your speakers, as the customer support actually tells us to do!
- Also, if you use Ethernet to router on one of the pair, you should do it also on the other. Otherwise, it can get actually worse, because master will use Ethernet to do (7), but from the router down, it will still be Wi-Fi, and in some cases it can be worse than PLC.
- If you are 100% wireless fan, you should get a decent Wi-Fi router and configure all your Phantoms on the 5 GHz network, ideally, checking the channel congestion first.
- Forced PLC can solve all your issues... or create new ones. It depends on your electrical cabling, your equipment, but also that of your neighbours.
- Remember that low latency setting ONLY applies to optical / analog inputs.
- I agree with @ofrappier that direct Ethernet connection is probably the best compromise, if it works for you. You can really go down on latency for the TV scenario, and you bypass your home router completely for the streaming. No hole drilling is involved and the ugly cable is hidden behind your TV. It is not known if you still need Wi-Fi on the non-master for (9), but you will definitely need it on both speakers for (1) and on the master for (2) and (4).
- Last resort: full Ethernet to router + a good router with good Wi-Fi for (1), (2 (except wired laptop or NAS)) and (3).

Note on a multi-room case:
I can imagine a number of ways to do (8) with a combination of one or several methods of (7), but based on the fact that "network interface" option in the app v1.11 stayed exactly the same as before, it is probable that the same method is used for all non-masters when forced to PLC or Wi-Fi. There may be a more complex algorithm hiding behind "auto" selection, but there are too many unknowns here. For a solid multi-room case... wire everything in Ethernet.

(Disclaimer: I have 2xGold + 2xReactor and the multi-room is working just fine in Spotify Connect + full Auto... (no Ethernet))
An overlong post... again. Sorry folks! I hope it helps someone.

Most excellent post!
Thank you.