Modeling Microphone Noise

Campbell’s Corner – By Dick Campbell

It’s time to go a little ‘upscale’ and get a close look at a different kind of modeling – electret microphones. Some manufacturers call them ‘pre-charged’ or “pre-polarized” condensers. Originally they were called ‘capacitor’ mics, and so it is logical to model this type of mic as an electrical capacitor. Of course, there are other elements to model because there is no such thing as a ‘perfect’ capacitor in the real world, and whatever gets designed has to be packaged, amplified, and analyzed acoustically. So, the ‘perfect’ capacitor is surrounded by stuff and it all has to go into the model to predict real-world behavior.