Hello @4367,
The number of hops between the devices are pretty substantial here, the Core sends the Audio through your router to the Sonos so it has to bounce from Basement -> Living Room -> Basement again. If you try to eliminate one of these hops and connect the Core directly to your router, do you notice an improvement in the stutters? You can also use another Roon Remote to control the Core so installing Roon on your iOS device/Android and then controlling it this way will be a good test.
Does the stutter occur with all kinds of content, even 44.1/16? For the router you have I would also check the settings to make sure you have “Enable Multicast Routing” checked in the options as that has helped in the past.
Yes, you will need some kind of streamer to get the music in the basement. If you have a hardwire connection going from your Router to the basement then installing an unmanaged switch is recommended for best stability. Popular choices for Ethernet based endpoints include ultra/microRendu (ready to go) or Raspberry Pi’s (some assembly may be required) or DACs themselves that support Ethernet connections and are RoonReady.
Please let me know if you are able to run the test with the Core connected directly to your router and if making that multicast settings help. Would also be a good data point to know if the Living Room Sonos behaves as expected.
Thanks,
Noris