Condenser microphones have thin, electrically conductive diaphragms that move back and forth when sound waves hit them, changing the distance between the diaphragm and a back plate and converting sound into an electrical signal. However, the signal is fragile and requires an impedance converter and external power. Condenser microphones offer superior sound quality to dynamic microphones due to their extremely low-mass diaphragms, which can follow sound waves more accurately, resulting in a wider frequency response and better transient response. They became more convenient with the invention of phantom power, which supplies the needed voltage through microphone cables.