ants:

The app is called MacPlayer and works thanks to the magic of Spotify Connect. The speaker itself streams and plays the music, and the Mac simply tells the speaker which song to play (as well as volume, current playlist, shuffle mode and other settings). Communication is over Wifi.

The app performs well on a stock SE/30, although it does rely on a bit of help from the on-board OpenWRT Wifi router to handle the HTTPS communication with the Spotify API. The router has stunnel installed on it, which acts as a HTTP to HTTPS tunnel. I updated the MacWifi Extension to allow the Mac to create SSL tunnels on the router as needed. Here’s a video of how the app performs (no music unfortunately due to Copyright):

I don’t understand half of what he is talking about but it looks amazing.