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 public, for example for announcements of movements at large and noisy air and rail terminals.
It increases the apparent volume (loudness) of a human voice, musical instrument, or other acoustic sound source or recorded sound or music. PA systems are used in any public venue, Office that requires that an announcer, performer, etc. be sufficiently audible at a distance or over a large area.
The goal of a PA system is to provide “public address”, or a way to transmit audio communication to a group.
The transmission can begin with a microphone, which is a device that can assist in magnifying an audio source’s volume. A microphone is classified as a device that transforms sound into an electrical signal.
The amplifier’s job is to magnify the audio signal by manipulating its varying frequency qualities. The gain in an amplifier refers to the decibel level of the sound coming out of the speakers. Another quality, Output Dynamic Range, refers to the loud and soft levels of a specific channel’s sound. Too low of output could result in just broadcasting noise; too high output can lead to distortion.
The speaker is the output end of the PA system, transforming the electrical signal back into sound that a group can hear.