Centralized multi-room audio setup with MPD and spotify integration - Solutions - openHAB Community
Review: Antipodes Audio S40 Music Server
How to build your open source multi-room sound system | by Fabio Manganiello | The Monolith | Medium
GitHub - bosim/socompd: A minimal implementation of mpd that relay commands to Sonos. So this program acts as a mpd proxy i.e. you can use a mpd client for controlling your Sonos