We use Sonos at the office for easy music-access across the entire building. We've got 8 Sonos AMPs linked to Bowers And Wilkins built-in ceiling speakers, combined with a couple of Play:3 and Play:1 units for smaller offices. It's an elegant system. We hooked up one radio, tuned to Studio Brussel to the line-in of one of the AMPs, thus combining one of Belgiums better radio stations with a zero-bandwidth solution. It's better to share the line-in of an AMP than to have a dozen Sonos devices all streaming high quality internet radio all day.
Users who do want something different can use the build-in Tune-In radio to pick a radio station of their preference. All hooked up to ethernet.
A perfect solution. Or so we thought.
For a while now we had some serious issues on the network. Switches would randomly lock, internet would grind to a stop and internal network traffic would just drop.
Frustrated and confused, because there was no obvious culprit to be found, I spent last weekend rewiring and checking our entire server-backbone. To make this process easier I decided to turn off any devices that weren't necessary to work productively.
Accidentally I noticed that the network behaved a lot better after I disconnected the switch that contained all the Sonos devices. And said switch still acted weird even when unpatched from the rest of the network.
Turns out: Managed switches and wired Sonos is a big no-go. If you have more than one Sonos connected via ethernet, things may go wrong.
Since Sonos also talk to each other, they have the downside of possibly creating a Broadcast Storm on your network, and thus taking down a part or all of the network.
Luckily there's a solution: either use a dumb unmanaged switch (not gonna happen), or adjust the Spanning Tree State settings of your switch(es). So a few configuration changes later, we again have a stable setup.
If you happen to have some managed switches, and think about hardwiring your Sonos to reduce the load on your wi-fi network: file this article for future use. It may save you from spending a sunny afternoon in a server room surrounded by ethernet cables and switches.