page_title: Public address system
section_title: Large venue systems
hierarchical_section_title: Public address system / Large venue systems
caption_attribution_description: English: Meyer Milo line array with EAW subs and an EAW side fill array Mayer Milo line array EAW side fill array EAW subs
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: For popular music concerts, a more powerful and more complicated PA System is used to provide live sound reproduction. In a concert setting, there are typically two complete PA systems: the "main" system and the "monitor" system. Each system consists of a mixing board, sound processing equipment, amplifiers, and speakers. The microphones that are used to pick up vocals and amplifier sounds are routed through both the main and monitor systems. Audio engineers can set different sound levels for each microphone on the main and monitor systems. For example, a backup vocalist whose voice has a low sound level in the main mix may ask for a much louder sound level through her monitor speaker, so she can hear her singing. 
  The "main" system (also known as Front of House, commonly abbreviated FOH), which provides the amplified sound for the audience, typically uses a number of powerful amplifiers that drive a range of large, heavy-duty loudspeakers—including low-frequency speaker cabinets called subwoofers, full-range speaker cabinets, and high-range horns. A large club may use amplifiers to provide 3000 to 5000 watts of power to the "main" speakers. An outdoor concert may use 10,000 or more watts.
  The monitor system reproduces the sounds of the performance and directs them towards the onstage performers (typically using wedge-shaped monitor speaker cabinets), to help them to hear the instruments and vocals.  In British English, the monitor system is referred to as the "foldback". The monitor system in a large club may provide 500 to 1000 watts of power to several foldback speakers; at an outdoor concert, there may be several thousand watts of power going to the monitor system.
  At a concert using live sound reproduction, sound engineers and technicians control the mixing boards for the "main" and "monitor" systems, adjusting tone, levels, and overall volume.
  Touring productions travel with relocatable large line-array PA systems, sometimes rented from an audio equipment hire company. The sound equipment moves from venue to venue along with various other equipment such as lighting and projection.
caption: A line array speaker system and subwoofer cabinets at a live music concert
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