Kinda off topic as it's not directly about the music but i thought those who love Quake and the soundtrack would enjoy seeing this little mini-doc that came out about the game. (although be warned, it's very nerdy and technical but we're NIN fans, we like things nerdy and technical right?)
They do of course touch briefly on NIN's killer soundtrack work and the music format for about a minute or so at 7:35 mark.