A public address system is an electronic amplification system used as a communication system in public areas. It consists of an amplification setup with an amplifier and loudspeakers, used to reinforce a given sound (e.g. a person making a speech, prerecorded music, or a live musical performance) so that the audience can hear it clearly. The public address system also refers to an audio transmission system used in institutional and commercial buildings, in which input from a microphone or prerecorded music is amplified and sent to speakers throughout the building.