Public Address System

A public address or "PA" system is an electronic amplification system with a mixer, amplifier and loudspeakers, used to reinforce a given sound, e.g., a person making a speech, prerecorded music, or message, and distributing the sound throughout a venue. PA systems are often used in venues such as school churches, in institutional and commercial buildings, to read announcements or declare states of emergency. Intercom systems, which are often used in schools, also have microphones in each room so that the occupants can reply to the central office.