First phase of the multi-room audio "Make playing to any one room easier" is done. Use Spotify, Airplay, MPD or a web browser (e.g. http://kitchen.home.whalebarn.com).
Key things:
The volume control in your app (be it Spotify, Airplay, MPD or whatever) is the only volume control that matters. If you crank it up, things are going to be loud.
Volume adjustments are a bit sluggish (~1s)
Snapcast goes away - each room switches its streams automatically
If someone leaves their Spotify stream playing in a room there's not much anyone can do about that. (But the next phase fixes this!
trello{target="blank"})
More flimsy guidance on the wiki: Media Players
Trello: Centralized Media Infrastructure Part 1
Also, some Python was harmed in the making of this: github:markferry/multizone-audio