The public address system ( PA system ) is an electronic system made up of microphones, amplifiers, loudspeakers, and related equipment. This increases the volume of sound (voice) of human voice, musical instruments, or other acoustic sound sources or sound or recorded music. PA systems are used in public places that require broadcasters, players, etc. Simply heard in the distance or over a large area. Typical applications include sports stadiums, vehicles and public transport facilities, as well as live or recorded music venues and venues. PA systems may include multiple microphones or other sound sources, mixing consoles to combine and modify multiple sources, and multiple amplifiers and loudspeakers for louder volumes or wider distributions.
Simple PA systems are often used in small places such as school auditoriums, churches and small bars. PA systems with many speakers are widely used to make announcements in buildings and public, institutional and commercial locations - such as schools, stadiums, and passenger and aircraft ships. The intercom system, installed in many buildings, has speakers throughout the building, and microphones in many rooms so residents can respond to announcements.
The term, sound reinforcement system generally means a special PA system for music or live performances. In the UK, any PA system is sometimes referred to as Tannoy, after the company's name is now owned by TC Electronic Group, which supplies a large number of PA systems previously used in the UK.
Video Public address system
Sistem awal
Megaphone
From Ancient Greece until the nineteenth century, before the invention of loudspeakers and electric loudspeakers, megaphone cones were used by people who spoke to a wide audience, to make their sound project more into space or large groups. Megaphones are usually portable, usually hand-held, cone-shaped acoustic horns used to amplify a person's voice or other sound and steer it in the given direction. The sound is inserted into the narrow end of the megaphone, holding it to the face and talking into it. The project sound came out of the cone end. The user can direct the sound by pointing the wide end of the cone in a certain direction. In 2010, cheerleading was one of the few areas where the nineteenth century cone was still used to project sound. This device is also called "talk-trumpet", "loudspeaker" or "hard hailer".
Automatic Enunciator
In 1910, Chicago Automated Electric Company, Illinois, which has become a key supplier of automatic telephone switchboard, announced that it has developed a loudspeaker, marketed under the name of Automatic Identification . Company president Joseph Harris foresaw some potential usage, and original publications emphasize the value of this invention as a public address system of hotels, allowing people in all public spaces to hear announcements. In June 1910, the initial "semi-public" demonstration was given to a newspaper reporter in the Automatic Electric Company building, where the speaker's voice was transmitted to a loudspeaker stationed in dozens of "across the building" locations.
Sometime later, the Word Automation Company was formed in Chicago to market a new device, and a series of promotional installations followed. In August 1912, a large outdoor installation was made at a water carnival held in Chicago by the Yacht Association and Forced Ship Clubs of America. Seventy-two loudspeakers were hung at a distance of forty feet (12 meters) along the pier, covering a total of one and a half miles (800 meters) from the stands. The system was used to announce race reports and descriptions, bringing a series of speeches on "The Chicago Plan", and providing interracial music.
In 1913, several units were installed throughout Comiskey Park's baseball stadium in Chicago, both for making announcements and for providing musical interludes, with Charles A. Comiskey quoted as saying: "The day the megaphone has passed in our garden." The company also set up an experimental service, called Musolaphone, which is used to send news and entertainment programs to home and business customers in southern Chicago, but this effort was short-lived. The company continued to market word-makers to make announcements in companies such as hospitals, department stores, factories, and railway stations, even though the Automatic Enunciator Company was dissolved in 1926.
Edwin Jensen and Peter Pridham of Magnavox began experimenting with sound reproduction in the 1910s. Working from a laboratory in Napa, California, they filed the first patent for a rolling loudspeaker that moved in 1911. Four years later, in 1915, they built a dynamic loudspeaker with a 1 inch (2.5 cm), 3- 7.6 cm) wavy diaphragm and 34 inches (86 cm) horn with 22 inches (56 cm) aperture. The electromagnet creates a flux field of about 11,000 Gauss.
Their first experiment used a carbon microphone. When the 12 V battery is connected to the system, they experience one of the first examples of acoustic feedback, a normally unwanted effect often marked with a high-pitched sound. They then put the loudspeaker on the laboratory roof, and the claim says that a reinforced human voice can be heard 1 mile (1.6 km). Jensen and Pridham refine the system and connect the phonograph to the loudspeaker so it can broadcast the recorded music. They did this on a number of occasions, including once in Napa's laboratory, at the Panama-Pacific International Fair, and on December 24, 1915 at San Francisco City Hall with Mayor James Rolph. This demonstration is an official presentation of the work system, and about 100,000 people gathered to listen to music and Christmas speeches "with absolute peculiarities".
The first outdoor broadcast was made a week later, once again watched by Jensen and Pridham. On Dec. 30, when California Governor Hiram Johnson was too ill to give a private speech, a loudspeaker was installed at the Civic Auditorium in San Francisco, connected to Johnson's home several miles away by cable and microphone, from where he delivered his speech. Jensen oversaw the governor using a microphone while Pridham operates the loudspeaker.
The following year, Jensen and Pridham filed a patent for what they called their "Sound Magnifying Phonograph". Over the next two years they developed their first valve amplifier. In 1919 it was standardized as a 3-phase 25 watt amplifier.
The system was used by former US president William Howard Taft in a speech at Grant Park, Chicago, and was first used by the current president when Woodrow Wilson spoke to 50,000 people in San Diego, California. Wilson's speech was part of his national tour to promote the establishment of the League of Nations. It was held on September 9, 1919 at City Stadium. Like the San Francisco installation, Jensen watched the microphone and Pridham loudspeakers. Wilson spoke in two large horns mounted on his platform, which channeled his voice into the microphone. Similar systems were used in later years by Warren G. Harding and Franklin D. Roosevelt.
Marconi
In the early 1920s, Marconi had set up departments dedicated to public addresses and began producing loudspeakers and amplifiers to meet ever-increasing demand. In 1925, George V used such a system at the United Kingdom Exhibition, addressing 90,000 through six loudspeakers over long distances. The use of public speakers brings attention to the possibility of such technology. The 1925 Royal Air Force contest at Hendon Aerodrome uses Marconi's system to allow broadcasters to speak to the masses, as well as strengthen the band. In 1929, the Schneider Trophy race at Calshot Spit used a public address system that had 200 horns, weighing a total of 20 tons.
The late 1920s 1930
Engineers created powerful first loudspeakers and loudspeakers for public address systems and cinemas. The large PA system and cinema sound system are very large and very expensive, so it can not be used by most of the tour musicians. After 1927, a smaller, portable AC powered PA system that could be plugged into a regular outlet "quickly became popular with musicians"; indeed, "... Leon McAuliffe (with Bob Wills) is still using a portable carbon mic and PA at the end of 1935." During the late 1920s to mid 1930s, small portable PA systems and guitar combo amplifiers were quite similar. The initial amp has a "one volume control and one or two input jacks, a coil speakers field" and a thin wood cabinet; amazingly, this early amp has no tone control or even an on-off switch. Portable PA systems that you can plug into a wall outlet emerged in the early 1930s when the introduction of electrolytic capacitors and rectifier tubes allowed integrated power supplies that could be plugged into a wall socket. Previously, the amplifier needed a lot of battery packs.
Electric megaphone
In the 1960s, an electric loudspeaker version of the megaphone, which uses loudspeakers, amplifiers, and folded horns, largely replacing the basic conical cone megaphone. A small battery-powered megaphone hand held by fire and rescue workers, police, protesters, and people talking to outdoor audiences. With many small handheld models, a microphone is mounted on the back of the device, and the user holds the megaphone in front of his mouth to use it, and presses the trigger to turn on the amplifier and loudspeaker. Larger electric megaphones may have a microphone mounted by a cable, allowing someone to speak without their faces obscured by a blazing horn.
Maps Public address system
Small system
The simplest, the smallest PA system consists of a microphone, amplifier, and one or more loudspeakers. This type of PA system often provides 50 to 200 watts of power, often used in small places such as school auditoriums, churches, and coffee shop stages. Small PA systems can be extended to entire buildings, such as restaurants, shops, primary schools or office buildings. Sound sources such as CD or radio players can be connected to the PA system so that music can be played through the system. A smaller battery-powered 12-volt system can be installed in vehicles such as tour buses or school buses, so tour guides and/or drivers can talk to all passengers. Portable systems may be battery powered and/or activated by inserting the system into a power outlet. It can also be used by people who handle smaller groups such as information sessions or team meetings. The battery-powered system can be used by a guide that speaks to clients on a walking tour.
The public address system consists of input source (microphone, voice player devicrs, etc.), Amplifier, control and monitoring equipment (eg LED indicator lights, VU meters, headphones), and loudspeakers. Ordinary input includes a microphone for talking or singing, direct input from a musical instrument, and a recorded sound playback device. In non-performance applications, there may be a system that operators or automated equipment use to select from a number of previously recorded messages. These input sources are inserted into the preamplifiers and signal routers that direct the audio signal to the selected zone of the facility (for example, for only one part of the school). The preamplified signal then goes into the amplifier. Depending on local practice, this amplifier usually amplifies the audio signal to the 50V, 70V, or 100V line speaker level. The control equipment monitors the amplifier and speaker path for errors before reaching the loudspeaker. The control equipment is also used to separate the zones within the PA system. The loudspeaker converts the electrical signal into sound.
Large system
Some PA systems have speakers covering more than one building, which extends to all campus campuses, offices or industrial locations, or an entire outdoor complex (eg, athletic stadium). A large PA system can also be used as a warning system during emergencies.
PA system based on subwoofer size and approach
Sistem paging telepon
Some private branch branch (PBX) telephone systems use paging facilities that act as a link between the phone and the PA amplifier. In other systems, paging equipment is not built into the telephone system. Instead, the system includes a separate paging controller that connects to the trunk port on the phone system. The paging controller is accessed either as a designated directory number or a central office row. In many modern systems, paging functions are integrated into the phone system, so the system can send announcements to the speakerphone.
Many retailers and offices prefer to use the phone system as the only access point for the paging system, because its features are integrated. Many schools and other larger institutions no longer use large and large microphone PA systems and have switched to paging phone systems, as they are accessible from many different points in the school.
PA via IP
PA over IP refers to PA paging and intercom systems that use Internet Protocol (IP) networks, not central amplifiers, to distribute audio signals to paging locations across buildings or campuses, or anywhere within network coverage IP, including the Internet. Amplifiers installed in networks and intercom units are used to provide communication functions. At the end of the transmission, the computer application transmits digital audio streams over a local area network, using audio from the computer sound card input or from stored audio recordings. At the receiving end, a special intercom module (sometimes known as an IP speaker) receives this network transmission and reproduces analog audio signals. This is a special small network equipment that can be addressed by an IP address, just like any other computer on the network.
WMT PA Systems
Wireless Mobile Telephony (WMT) PA Systems refers to PA paging and intercom systems that use any form of Wireless cellular phone systems such as GSM networks rather than central amplifiers to distribute audio signals to paging locations in buildings or campuses, or other locations. GSM mobile networks are used to provide communication functions. At the other end of the transmission, a PSTN Phone, a cellular phone, a VOIP phone or other communication device that can access and make audio calls to a GSM-based mobile SIM card can communicate with it. In the receiver, the GSM transceiver receives this network transmission and reproduces the analog audio signal through the Power Amplifier and speakers. It was pioneered by Stephen Robert Pearson of Lancashire, UK who granted patent for the system, which also incorporates control functions. Using the WMT (GSM) network means that live announcements can be made anywhere in the world where there is WMT connectivity. Patents cover all forms of WMT ie, 2G, 3G, 4G..... xxG. The UK company called Remvox Ltd (REMote VOice eXperience) has been designated under license to develop and manufacture products based on technology.
PA length line
The Long-Line Public Address System (LLPA) is a public address system with a distributed architecture, usually in a large geographical area. This type of system is commonly found on rail, light rail, and metro industry, and let announcements be triggered from one or more locations across the network through low-bandwidth copper inheritance, usually PSTN lines using DSL modems, or media such as fiber optics, or GSM -R, or IP-based networks.
Rail systems typically have interfaces with passenger information system (PIS) servers, at each station. This is related to the practice of descriptor, which states the location of rolling stock in the network of sensors on the trackside signal equipment. PIS calls a saved message to be played from the local or remote digital voice announcement system, or a series of message fragments to be assembled in the correct order, for example: "/the/23.30/First_Great_Western/Night_Riviera_sleeper_service/from/London_Paddington/to/Penzance/..../will depart from platform/single/train is formed from/12_carriages/. "The messages are routed over the IP network and played on local amplification equipment. Together, PA, routing, DVA, passenger displays and PIS interfaces are referred to as customer information systems (CIS) , a term often used interchangeably with the passenger information system .
Small place system
Small clubs, bars and coffee shops use fairly simple set-ups, with front speaker cabinets (and subwoofers, in some cases) intended for viewers, and monitor speaker cabinets aimed at players so they can hear vocals and instruments them. In many cases, the front speaker is raised, either by placing it on a pole or by "flying" them from an anchor on the ceiling. The Front of House speaker is elevated to prevent the sound absorbed by the first few lines of the audience. The subwoofer does not need to be raised, because the deep bass is omnidirectional. In the smallest coffee shop and bar, audio mixers may be on stage so players can mix their own sound levels. In larger bars, the audio mixer can be placed inside or behind the seating area of ​​the audience, so an audio engineer can listen to the mix and adjust the sound level. Adjustments to the monitor speaker mix can be performed by an audio engineer using the main mixer board, or they can be made by a second audio engineer using a separate mixing board.
Large place system
For popular music concerts, more powerful and more complex PA Systems are used to provide live sound reproduction. In concert arrangements, there are usually two complete PA systems: the "main" system and the "monitor" system. Each system consists of mixing boards, sound processing equipment, amplifiers, and speakers. The microphones used to pick up vocal sounds and amplifiers are routed through the main system and monitor. Audio engineers can set different sound levels for each microphone on the main system and monitor. For example, a backup vocalist whose voice has a low sound level in the main mix may require a much louder sound level through his monitor loudspeakers, so he can hear his singing.
- The "main" system (also known as Front of House , commonly abbreviated as FOH), which provides a reinforced voice for the audience, typically uses a number of powerful amplifiers that drive a large variety, loudspeakers heavy duty - including low frequency speaker cabinets called subwoofers, full speaker cabinets, and remote horns. A large club can use amplifiers to deliver 3000 to 5000 watts of power to the "main" speakers. Outdoor concerts can use 10,000 or more watts.
- The monitor system reproduces the performance sound and directs it to the players on stage (usually using a wedge-shaped monitor cabinet), to help them hear instruments and vocals. In English English, the monitor system is referred to as "foldback". Monitor systems in large clubs can provide 500 to 1000 watts of power to multiple foldback speakers; in an outdoor concert, there may be several thousand watts of power coming into the monitor system.
In concerts using live sound reproduction, sound technicians and technicians control the mixer boards for "main" and "monitor" systems, adjusting overall tone, level and volume.
Tour production trips with a large PA-line array system line-relocatable, sometimes rented from audio equipment rental companies. The sound equipment moves from place to place along with other equipment such as lighting and projection.
Acoustic feedback
All PA systems have potential for audio feedback, which occurs when the microphone picks up sound from the speakers, which is reinforced and sent through the speakers again. This often sounds like a loud noise or a high-pitched scream, and can occur when the system volume is raised too high. Feedback only occurs when the loop gain of the feedback loop is greater than one, so it can always be stopped by decreasing the volume sufficiently.
Sound engineers take several steps to maximize earning before feedback, including keeping the microphone remotely from the speakers, ensuring that the directional microphone is not directed to the speakers, keeping the volume level above the stage down, and lowering the gain level at the frequency at which feedback occurs, using a graphic equalizer, parametric equalizer, or notch filter. Some mixing consoles and effects units in the 2010 era have automatic feedback that prevents circuits.
The feedback prevention tool detects the start of undesirable feedback and uses the right notch filter to decrease the acquisition of the feedback frequency. Some automatic feedback detectors require the user to "adjust" the frequency that is easily affected by the feed by increasing the gain (during sound proofing) until some feedback starts to occur. The device then maintains this frequency in its memory and is ready to cut it. Some automated feedback prevention tools can detect and reduce new frequencies other than those found in sound proofing.
See also
- Announcer
- Instrument booster
- Sound reinforcement system
References
External links
Source of the article : Wikipedia
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