You would think hardwiring Sonos speakers in a 5.1 setup would be easier than setting them up as wireless... but nope. It's not. It took me a while to figure out how to do it mainly because there isn't a clear error.
When I first attempted hardwire the system everything actually worked but only for about 5 minutes. What happened next was that my whole network went down. The reason why this happened is due to what's called a "network storm". My router was overwhelmed with routing network packets generated by the Sonos system in this configuration. Seems like there's a loopback created because of Sonos' use of Spanning Tree Protocol (STP) simultaneously across WiFI and ethernet connections when both are available to a speaker. The only way to get rid of this issue easily is to connect the system into a router/switch that has STP (Spanning Tree Protocol) support.
If you don't have access to one of these routers/switches then one option is to connect and disable the wifi for each speaker in a sequential fashion. The way I did it was as follows:
- Connect Playbar to ethernet (wait about 10 minutes)
- Enter Sonos app on phone, enter playbar menu, disable wifi
- Connect right rear speaker to ethernet
- On sonos app disable the wifi for the right rear speaker
- .... and so on for the remaining speakers
With this procedure everything works.