Study of Room Noise

The following figures are power spectra of the noise in the room, with different combinations of the four different air conditioning units running. The legend in the top right hand corner of each graph explains which AC units, if any, were running when the power spectrum was taken.
The room noise has been improved recently, for actual power spectrum, follow this link.

Graph of total room noise (all AC/UPS operating).





The UPS system (Powerware 9315, 500kVA/400kW) has a lot of loose sheet metal inside. The internal cooling fan(s) cause this metal to resonate and vibrate, and makes quite a racket. This should be fixable by opening up the unit and snugging/tightening all of the internal sheet metal screws. For a wav file of the sound of the UPS system
(all AC units turned off),
please click here.