What is "Phantom Powering"?

Phantom Powering

A technique for supplying the preamplifier supply voltage to condenser microphones whereby half of the DC flows through each signal conductor and returns to the voltage source via the cable shield. In this way, the DC-voltage becomes “invisible” to the circuitry that carries the microphone signal. The voltage is standardized to 48 volts only. Older equipment can work with lower voltages like 24 or 18 volts.