[More information] DC fan DC fan DC fan http://www.szdosense.com addition to the cooling effect, cooling fan operating noise is also widespread concern. Fan noise is the size of the generated noise of the fan work, influenced by many factors, in decibels (dB). Cooling fan noise when measuring the noise needs to be less than 17dB in the muffler chamber is performed, one meter away from the fan and the cooling fan along the axis of rotation aligned with the fan air intake port, the use of A-weighted manner measurement. The spectral characteristics of the cooling fan noise is also very important, so we must also use a spectrum analyzer records the fan noise frequency distribution, the general requirements of the fan noise to be as small as possible, but can not exist different tone. SHENZHEN woo Electronics Co., Ltd. for your friendship Recommended: Dual ball bearing fan http://www.szdosense.com/products-detail.asp?cpid=81 AC AC cooling fan http://www.szdosense.com/products -detail.asp? cpid = 82