page_title: Public address system
section_title: Large systems
hierarchical_section_title: Public address system / Large systems
caption_attribution_description: Public Address System assembled in racks for a major international airport consisting of amplifiers, mixers and routers
context_page_description: A public address system is an electronic system comprising microphones, amplifiers, loudspeakers, and related equipment. It increases the apparent volume of a human voice, musical instrument, or other acoustic sound source or recorded sound or music. PA systems are used in any public venue that requires that an announcer, performer, etc. be sufficiently audible at a distance or over a large area. Typical applications include sports stadiums, public transportation vehicles and facilities, and live or recorded music venues and events. A PA system may include multiple microphones or other sound sources, a mixing console to combine and modify multiple sources, and multiple amplifiers and loudspeakers for louder volume or wider distribution.
  Simple PA systems are often used in small venues such as school auditoriums, churches, and small bars. PA systems with many speakers are widely used to make announcements in public, institutional and commercial buildings and locations—such as schools, stadiums, and passenger vessels and aircraft.
context_section_description: Some PA systems have speakers that cover more than one building, extending to an entire campus of a college, office or industrial site, or an entire outdoor complex (e.g., an athletic stadium). A large PA system may also be used as an alert system during an emergency.
  PA systems by size and subwoofer approach
caption: Public address system consisting of amplifiers, mixers, and routers for a major international airport
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