1. Current Measurement
The current measurement is directly read from the testing instrument, typically in microamperes (μA).
2. Sensitivity Measurement
First, use a standard microphone to calibrate the testing instrument with a sound pressure level of 94dB. Then, place the microphone under test in the calibrated sound chamber, using test probes to measure the two terminals of the microphone. Pay attention to the orientation of the probes and the microphone's operating voltage and load resistance. The sensitivity at 70Hz and 1kHz can be directly read from the instrument.
3. Directionality Measurement
This test must be performed in a soundproof room using a B&K 2012 testing instrument and a B&K rotating platform for measurement.
4. Frequency Response Curve Measurement
This test also requires a soundproof room and the use of a B&K 2012 testing instrument along with a B&K rotating platform.
5. Signal-to-Noise Ratio (SNR) Measurement
First, measure the microphone's sensitivity. Then, measure the noise level in the soundproof room under the same conditions. It is best to use dry batteries to minimize testing errors caused by other power sources. The SNR is then calculated using the formula: SNR = Sensitivity Level / Noise Level, and the result is expressed in logarithmic scale.
6. Maximum Sound Pressure Level Measurement
This test is conducted in a soundproof room using a B&K 2012 testing instrument. Gradually increase the sound pressure level while monitoring for distortion. When the distortion reaches 3%, the corresponding sound pressure level is recorded as the Maximum Sound Pressure Level (MAX SPL). The MAX SPL should be greater than 115 dB SPL.
