FurnaceLoop.ogg, FurnaceStart.ogg, FurnaceStop.ogg
  by Dynamicell (http://www.freesound.org/people/Dynamicell/sounds/17548/), License: CC Sampling Plus 1.0
  
Pop.ogg
  by Traveler (http://www.freesound.org/people/Traveler/sounds/16064/), License: CC Sampling Plus 1.0