Capacitor microphones consist of two electrically conductive capacitor plates, one fixed and one movable. Between the plates, an electric field is built up by means of tormented voltage. When the movable plate (membrane) vibrates in step with the sound wave, the distance between them and there with the capacitance changes. These are then converted to an electrical signal. Because the membrane can be made very thin and light, the compliance becomes good with high signal quality.