Figure (4.28) is a simplified versionofa typical’ capacitor microphone. The pressure response is found by assuming a uniform pressure Pi to exist all around the microphone at any instant of time. This is actually the case ‘of sufficiently low sound frequencies but reflection and diffraction effects distort this uniform field at higher frequencies. The diaphragm is generally a very thin metal membrane which is stretched by suitable clamping arrangement. Diaphragm thickness ranges from about 0.0025 to 0.050 mIIl:~ The diaphragm is deflected