Hello people at Congress. I copied my c3 playlists over to YouTube from Tidal. This one is new for 39c3 and I would be using it if I was there for background music while walking around. Mostly relaxed pace ambient/techno/electronica, etc. with minimal vocals. More deep than bright.
YouTube - https://www.youtube.com/playlist?list=PL_b5aK5MAbnD8lxbyCQdTERhls7rZBFZq
Tidal (original) -
https://tidal.com/playlist/20755b8a-207c-46a4-b7bd-3bc7ac501e39
The YouTube one should work with the mobile client of your choice (tested in PipePipe).