In addition to the cooling effect, "220V Cooling Fan" operating noise is everyone throughout the importance of the problem. Fan noise is noise when the fan size seizure operations, affected by various factors that influence in decibels (dB). When measuring noise fan needs less than 17dB of noise muffler chamber conducted one meter intervals fan and align the fan inlet in the direction of "220V Cooling Fan" axis, the choice of A-weighted approach to measurement. The spectral characteristics of the fan noise is also very important, and therefore also need to record the fan noise spectrum analyzer frequency dispersal, the general needs of "220V Cooling Fan" noise to be as small as possible, but can not exist different tone.