orange-pi zero 2 boxes attached to wifi or ethernet for input and output to class D amp and speakers, also have to power them. You put the pi's running shairport sync where you want the speakers.
Eg plug the pi into power and the amp, plug the amp into power and the speakers. No other wires.
They all synchronise perfectly over wifi or ethernet, which is the point of shairport-sync. They identify themselves on your network as AirPlay 1 speakers. Note that they actually work with the spotify app directly in a reliable way just like AppleTV doesn't - your AppleTV will require a reboot every time you want it to be the output of spotify. So either I'm a better engineer with off the shelf parts and open source software than apple's full time paid professional engineers or maybe Spotify has a point when complaining about Apple non-competitive behaviour? I wish it were the former but somehow doubt it.
