I now use Sonos to stream audio content. Since we already have a very large media library on our server (Win 2016 essentials), and there are 6 of us in the house accessing it, I installed Subsonic for a more feudal category division.
Basically everything works as it should, we are really happy with this solution. There is one small (beauty) problem, though: how do I get a nice icon for the Subsonic service on the Sonos app?

https://www.dropbox.com/s/528xcw3b0rdwb ... 5.jpg?dl=0
Regards, Thomas
