...and they work great as a space heater - my R4B2 is in my bedroom keeping it a bit warmer and is quiet enough to sleep no problem. My R4B4 is actually a bit louder (8.7THs vs 8THs) so it's going off to be hosted for now.
FIX THE LOUDNESS, FIX THE NOISE!
THE ONLY SOLUTION THAT ACTUALLY WORKED FOR ME.
JUST SAYING This made my ANTMiner QUITE!!
http://www.chikenfeed.com/0011-miner-s7-noise-reduction-sound-reduce-of-s7-antminer