What is a public address system?
A public address system (PA system) is an electronic sound amplification and distribution system with a microphone, amplifier and loudspeakers, used to allow a person to address a large audience. For example: announcements of movements at large and noisy air and rail terminals.
The term is also used for systems which may additionally have a mixing console, and amplifiers and loudspeakers suitable for music as well as speech, used to reinforce a sound source, such as recorded music or a person giving a speech or distributing the sound throughout a venue or building.
Simple PA systems are often used in small venues such as schools & churches, PA systems with speakers are widely used to make announcements in public, institutional and commercial buildings and locations. Intercom systems, installed in buildings, have microphones in rooms allowing the occupants to respond to announcements.
The simplest PA systems consist of a microphone, an amplifier, and one or more loudspeakers. Simple and small PA systems of this type, often providing 50 to 200 watts of power. A sound source such as a Compact Disc player or radio may be connected to a PA system so that music can be played through the system.
Sound reinforcement systems and PA systems may use some similar components, but with differing application, although the distinction between the two is not precise. Sound reinforcement systems are for live music or performance, whereas PA systems are primarily for reproduction of speech.
School One-Way intercom system
Example of a 40 classroom one-way intercom system