The electret microphone consists of two parts: acoustic-electric conversion and impedance conversion. The key component of acoustic-electric conversion is the electret diaphragm. It is a very thin plastic film with a thin metal film evaporated on one side. Then, after passing through the high-voltage electric field electret, the charges of different polarity reside on both sides. The gold-evaporated side of the diaphragm faces outward and communicates with the metal shell. In the electret microphone, there is a field effect tube for preamplification, so the electret microphone needs a certain bias voltage during normal operation. CRY6151B Electroacoustic Analyzer supports multi-channel microphone synchronous acquisition test. The test items include parameters, such as sensitivity, distortion, SNR, and current. It can meet the requirements for laboratory testing and increase production capacity in many aspects.