Common microphone capsule parameter tests include the following: microphone current test, directional test, frequency response curve test, sensitivity test, and signal-to-noise ratio (S/N) test.
1. Microphone Current Test
The current value (μA) is directly read from the testing instrument.
2. Microphone Directionality Test
This test should be conducted in a standard anechoic chamber using the B&K 2012 testing instrument and the B&K rotating table.
3. Microphone Frequency Response Curve Test
This test should also be conducted in a standard anechoic chamber using the B&K 2012 testing instrument and the B&K rotating table.
4. Microphone Sensitivity Test
First, calibrate the testing instrument to a sound pressure level of 94 dB using a standard microphone. Then place the microphone capsule under test onto the calibrated sound chamber.
Use test probes to check the two terminals of the microphone capsule (pay attention to the direction of the probes). Be mindful of the capsule's operating voltage and load resistance. The sensitivity at 70 Hz and 1 kHz can be directly read from the testing instrument.
5. Microphone Signal-to-Noise Ratio (S/N) Test
First, test the microphone capsule's sensitivity. Then, under the same conditions, test the microphone's noise level in the anechoic chamber.
It is best to use dry batteries to reduce testing errors caused by other power sources. Then, calculate the S/N ratio using the formula: S/N = Sensitivity Level / Noise Level, and express it in logarithmic form.
