A use case that’s come up here a few times before: accessing Roon over VPN (Teleport/Wireguard, Tailscale) works well for connecting to the server, but since mDNS does not propagate, the zone you’re holding/sitting in front of cannot be used. I know there’s Arc – but it’s mobile only and a bit eh… different. Sometimes you just want the full flavored stuff. 
That’s exactly why I baked Tap for Roon: a small app running on a Raspberry Pi, leveraging Roon Bridge for zone control (so the zone stays local to the server) with loopback via ALSA. An extension monitors play state and launches a hosted raw PCM stream (with minimal buffering and a gentle drift control). On the remote device (now: iPhone, Mac) a companion app (Ear) captures and plays the stream (at full quality and aware of sample rate / bit depth changes).
The extension also passes on artwork, metadata and play controls – so the basically headless app shows this info on the Now Playing lock screen, with play controls controlling the Roon zone (pretty cool on iPhone).
Second part of the story could be this: a second Pi the second home, auto-connecting to the Tap stream upon play and passing on the stream to a connected USB DAC of choice. Two homes, one core, one Roon.
The first part is finished: I use it daily at work to use Roon with my AirPods (did I say it supports auto play/pause when in and out of the ears already?). Any interest in the second part?
