Looks like https://github.com/badaix/snapcast https://github.com/badaix/snapcast is powering the audio coordination under the hood. Noted at the bottom of this

Looks like https://github.com/badaix/snapcast https://github.com/badaix/snapcast is powering the audio coordination under the hood. Noted at the bottom of this page, https://www.balena.io/blog/turn-your-old-speakers-or-hi-fi-into-bluetooth-receivers-using-only-a-raspberry-pi/ https://www.balena.io/blog/turn-your-old-speakers-or-hi-fi-i...