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59-421: DOD originally stood for David Oreste DiFrancesco, who founded the company in 1973 with business partner and musician John Johnson. David was the original engineer who, with his business partner John, later sold the company to Harman International in 1990-'91. David now runs a company called Rolls Corporation. Over DOD's 40-year history, the company introduced many pedal lines and early multi-effect devices, like

118-414: A carbon microphone . When the 12 V battery was connected to the system, they experienced one of the first examples of acoustic feedback , a typically unwanted effect often characterized by high-pitched sounds. They then placed the loudspeaker on the laboratory's roof, and claims say that the amplified human voice could be heard 1 mile (1.6 km) away. Jensen and Pridham refined the system and connected

177-563: A passenger information system (PIS) server, at each station. These are linked to train describers, which state the location of rolling stock on the network from sensors on trackside signaling equipment. The PIS invokes a stored message to play from a local or remote digital voice announcement system, or a series of message fragments to assemble in the correct order , for example: " / the / 23.30 / Great_Western_Railway / Night_Riviera_sleeper_service / from / London_Paddington / to / Penzance / .... / will depart from platform / one / this train

236-628: A phonograph to the loudspeaker so it could broadcast recorded music. They did this on a number of occasions, including once at the Napa laboratory, at the Panama–Pacific International Exposition , and on December 24, 1915, at San Francisco City Hall alongside Mayor James Rolph . This demonstration was official presentation of the working system, and approximately 100,000 people gathered to hear Christmas music and speeches "with absolute distinctness". The first outside broadcast

295-645: A Marconi system to allow the announcer to address the crowds, as well as amplify 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 . Engineers invented the first loud, powerful amplifier and speaker systems for public address systems and movie theaters . These large PA systems and movie theatre sound systems were very large and very expensive, and so they could not be used by most touring musicians. After 1927, smaller, portable AC mains-powered PA systems that could be plugged into

354-466: A base station or mobile 2-way radio to a PA speaker located at distances that can measure in miles. The receiver and PA speaker combination is ideal in situations where traditional hard-wired PA installations are impractical, prohibitively expensive, or temporary. These receivers operate in business-band UHF and VHF 2-way licensed frequency bands, or in the MURS unlicensed frequencies. Installation requires setting

413-408: A building, and microphones in many rooms so occupants can respond to announcements. PA and Intercom systems are commonly used as part of an emergency communication system . The term sound reinforcement system generally means a PA system used specifically for live music or other performances. In Britain , PA systems are often known as tannoys after a company of that name that supplied many of

472-561: A central amplifier, to distribute the audio signal to paging locations across a building or campus, or anywhere else in the reach of the IP network, including the Internet. Network-attached amplifiers and intercom units are used to provide the communication function. At the transmission end, a computer application transmits a digital audio stream via the local area network, using audio from the computer's sound card inputs or from stored audio recordings. At

531-401: 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 Some private branch exchange (PBX) telephone systems use a paging facility that acts as a liaison between the telephone and a PA amplifier. In other systems, paging equipment

590-421: A distance from speakers, ensuring that directional microphones are not pointed towards speakers, keeping the onstage volume levels down, and lowering gain levels at frequencies where the feedback is occurring, using a graphic equalizer , a parametric equalizer , or a notch filter . Some 2010s-era mixing consoles and effects units have automatic feedback preventing circuits. Feedback prevention devices detect

649-756: 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. Intercom systems, installed in many buildings, have both speakers throughout

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708-411: A given direction. The sound is introduced into the narrow end of the megaphone, by holding it up to the face and speaking into it. The sound projects out the wide end of the cone. The user can direct the sound by pointing the wide end of the cone in a specific direction. In the 2020s, cheerleading is one of the few fields where a nineteenth century-style cone is still used to project the voice. The device

767-489: A microphone picks up sound from the speakers, which is re-amplified and sent through the speakers again. It often sounds like a loud high-pitched squeal or screech, and can occur when the volume of the system is turned up too high. Feedback only occurs when the loop gain of the feedback loop is greater than one, so it can always be stopped by reducing the volume sufficiently. Sound engineers take several steps to maximize gain before feedback , including keeping microphones at

826-580: A new DOD pedal called the "Boneshaker" distortion unit was released; this is a collaboration with boutique pedal builder Mark Wentz of Black Arts Toneworks. In September 2017, Harman announced that it was restructuring and consolidating its R&D facilities. This led to the engineering team at DOD/Digitech being fired in 2018, and the department integrated into Harman Pro. In April 2022, Cort Guitars ' parent company Cortek purchased DOD and DigiTech. Harman International Industries Harman International Industries, Inc. , commonly known as Harman ,

885-567: A number of businesses he sold to Beatrice. The company continued its growth with a string of acquisitions throughout the 1980s. Harman International went public in 1986 with a stock offering on the New York Stock Exchange . Cash from that sale was used to purchase other professional and consumer audio companies including Soundcraft , DOD Electronics Corp, Infinity and Epicure loudspeakers, Allen & Heath , dbx , Studer, Lexicon, AKG, BSS, Orban, Quested and Turbosound. A 2003 acquisition

944-473: A recorded sound playback device. In non-performance applications, there may be a system that operators or automated equipment uses to select from a number of standard prerecorded messages. These input sources feed into preamplifiers and signal routers that direct the audio signal to selected zones of a facility (e.g., only to one section of a school). The preamplified signals then pass into the amplifiers. Depending on local practices, these amplifiers usually amplify

1003-558: A regular wall socket "quickly became popular with musicians"; indeed, "... Leon McAuliffe (with Bob Wills ) still used a carbon mic and a portable PA as late as 1935." During the late 1920s to mid-1930s, small portable PA systems and guitar combo amplifiers were fairly similar. These early amps had a "single volume control and one or two input jacks, field coil speakers" and thin wooden cabinets; remarkably, these early amps did not have tone controls or even an on-off switch. Portable PA systems that could be plugged into wall sockets appeared in

1062-437: A restaurant, store, elementary school or office building. A sound source such as a compact disc player or radio may be connected to a PA system so that music can be played through the system. Smaller, battery-powered 12 volt systems may be installed in vehicles such as tour buses or school buses, so that the tour guide and/or driver can speak to all the passengers. Portable systems may be battery powered and/or powered by plugging

1121-580: A series of speeches about "The Chicago Plan", and provide music between races. In 1913, multiple units were installed throughout the Comiskey Park baseball stadium in Chicago, both to make announcements and to provide musical interludes, with Charles A. Comiskey quoted as saying: "The day of the megaphone man has passed at our park." The company also set up an experimental service, called the Musolaphone , that

1180-541: Is also called "speaking-trumpet", "bullhorn" or "loud hailer". In 1910, the Automatic Electric Company of Chicago, Illinois, already a major supplier of automatic telephone switchboards, announced it had developed a loudspeaker, which it marketed under the name of the Automatic Enunciator . Company president Joseph Harris foresaw multiple potential uses, and the original publicity stressed the value of

1239-711: Is an American audio electronics company. Since 2017, the company has been operating as an independent subsidiary of Samsung Electronics . Headquartered in Stamford, Connecticut , US, it has its own executive leadership team. Harman maintains major operations in the Americas , Europe , and Asia . Harman markets its products under various brands, including AKG , AMX , Arcam , Bang & Olufsen Automotive , Becker , BSS Audio, Crown , dbx , Harman Kardon , Infinity , JBL , Lexicon , Mark Levinson , Martin , Revel , and Soundcraft . Sidney Harman and Bernard Kardon founded

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1298-515: Is formed of / 12_carriages /." Messages are routed via an IP network and are played on local amplification equipment. Taken together, the PA, routing, DVA, passenger displays and PIS interface are referred to as the customer information system (CIS) , a term often used interchangeably with passenger information system . Small clubs, bars and coffeehouses use a fairly simple set-up, with front of house speaker cabinets (and subwoofers, in some cases) aimed at

1357-435: Is not built into the telephone system. Instead the system includes a separate paging controller connected to a trunk port of the telephone system. The paging controller is accessed as either a designated directory number or central office line. In many modern systems, the paging function is integrated into the telephone system, so the system can send announcements to the phone speakers. Many retailers and offices choose to use

1416-401: Is omnidirectional. In the smallest coffeehouses and bars, the audio mixer may be onstage so that the performers can mix their own sound levels. In larger bars, the audio mixer may be located in or behind the audience seating area, so that an audio engineer can listen to the mix and adjust the sound levels. The adjustments to the monitor speaker mix may be made by a single audio engineer using

1475-486: The "944 Chain-Reaction" and digital delays like the now sought-after PDS series. The '70s and early '80s 200, 400 and 600 series of stompboxes have become very collectable. 1970s gray " Overdrive Preamp 250s with LM741 op-amps fetch premium prices with collectors, with the yellow early '80s 250s not far behind. Later '90s DOD pedals have also become collectors items like the "Gonkulator", "Grind", "Buzz Box", "Meat Box", "Vibro Thang", and "Big Pig Fat" Distortion. Many of

1534-512: The 1910s. Working from a laboratory in Napa, California , they filed the first patent for a moving coil loudspeaker in 1911. Four years later, in 1915, they built a dynamic loudspeaker with a 1-inch (2.5 cm) voice coil , a 3-inch (7.6 cm) corrugated diaphragm and a horn measuring 34 inches (86 cm) with a 22-inch (56 cm) aperture. The electromagnet created a flux field of approximately 11,000 Gauss . Their first experiment used

1593-454: The 1970s, Harman accepted an appointment in the Carter administration as United States Deputy Secretary of Commerce and sold his company to conglomerate Beatrice Foods to avoid a conflict of interest. Beatrice sold many portions of the company, including the original Harman Kardon division. After he left his government position in 1978, he created Harman International Industries and reacquired

1652-542: The acquisition was completed, with Harman becoming the independent subsidiary of Samsung. Harman International Industries was to delist from NYSE in Q3/2007 due to a buy-out by KKR and Goldman Sachs Capital Partners . However, as of mid-September 2007, KKR announced they would back out of the deal. Coincident with the buy-out deal, Dinesh Paliwal was hired as company president and CEO in July 2007. On July 1, 2008, Sidney Harman

1711-443: The audience, and monitor speaker cabinets aimed back at the performers so they can hear their vocals and instruments. In many cases, front of house speakers are elevated, either by mounting them on poles or by "flying" them from anchors in the ceiling. The Front of House speakers are elevated to prevent the sound from being absorbed by the first few rows of audience members. The subwoofers do not need to be elevated, because deep bass

1770-410: The audio signals to 50 V, 70 V, or 100 V speaker line level. Control equipment monitors the amplifiers and speaker lines for faults before it reaches the loudspeakers. This control equipment is also used to separate zones in a PA system. The loudspeaker converts electrical signals into sound. Some PA systems have speakers that cover more than one building, extending to an entire campus of

1829-425: The automotive cyber-security firm TowerSec. This acquisition was notable for further demonstrating Harman's desire to expand beyond its traditional business areas of in-car audio and entertainment systems. On November 14, 2016, Harman entered into an agreement to be acquired by Samsung Electronics . In February 2017, Harman International shareholders voted in favor of the acquisition by Samsung. On March 10, 2017,

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1888-446: The communication function. At the transmission end, a PSTN Telephone, mobile phone, VOIP phone or any other communication device that can access and make audio calls to a GSM based mobile SIM card can communicate with it. At the receiving end, a GSM transceiver receives these network transmissions and reproduce the analogue audio signal via a Power Amplifier and speaker. This was pioneered by Stephen Robert Pearson of Lancashire, England who

1947-505: The early 1920s, Marconi had established a department dedicated to public address and began producing loudspeakers and amplifiers to match a growing demand. In 1925, George V used such a system at the British Empire Exhibition , addressing 90,000 via six long-range loudspeakers. This public use of loudspeakers brought attention to the possibilities of such technology. The 1925 Royal Air Force Pageant at Hendon Aerodrome used

2006-579: The early 1930s, when the introduction of electrolytic capacitors and rectifier tubes enabled economical built-in power supplies that could plug into wall outlets. Previously, amplifiers required heavy multiple battery packs. In the 1960s, an electric-amplified version of the megaphone, which used a loudspeaker, amplifier and a folded horn, largely replaced the basic cone-style megaphone. Small handheld, battery-powered electric megaphones are used by fire and rescue personnel, police, protesters, and people addressing outdoor audiences. With many small handheld models,

2065-452: The frequency you want to use on both the radio and the PA system, plus powering the wireless PA receivers. Wireless Mobile Telephony (WMT) PA Systems refers to PA paging and [intercom] systems that use any form of Wireless mobile telephony system such as GSM networks instead of a centralized amplifier to distribute the audio signal to paging locations across a building or campus, or other location. The GSM mobile Networks are used to provide

2124-576: The invention as a hotel public address system, allowing people in all public rooms to hear announcements. In June 1910, an initial "semi-public" demonstration was given to newspaper reporters at the Automatic Electric Company building, where a speaker's voice was transmitted to loudspeakers placed in a dozen locations "all over the building". A short time later, the Automatic Enunciator Company formed in Chicago order to market

2183-609: The loudspeaker. The following year, Jensen and Pridham applied for a patent for what they called their "Sound Magnifying Phonograph". Over the next two years they developed their first valve amplifier. In 1919 this was standardized as a 3-stage 25 watt amplifier. This system was used by former US president William Howard Taft at a speech in Grant Park , Chicago , and first used by a current president when Woodrow Wilson addressed 50,000 people in San Diego, California . Wilson's speech

2242-400: 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 their monitor speaker, so they can hear their singing. At a concert using live sound reproduction, sound engineers and technicians control

2301-524: The main mixing board, or they may be made by a second audio engineer who uses a separate mixing board. 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

2360-449: The marketing manager for DigiTech/DOD and continued to work on new DigiTech and DOD pedals until Samsung bought Harman International in 2018. On September 16, 2013, DOD returned with updated versions of the venerable "Overdrive Preamp/250", and "Phasor/201". Both feature true bypass, blue LEDs, modern power jack, lighter aluminum chassis, two tone flat-black and metal-flake paint jobs. The 2013 250 also features an LM741 op-amp to replicate

2419-671: The microphone is mounted at the back end of the device, and the user holds the megaphone in front of her/his mouth to use it, and presses a trigger to turn on the amplifier and loudspeaker. Larger electric megaphones may have a microphone attached by a cable, which enables a person to speak without having their face obscured by the flared horn. The simplest, smallest PA systems consist of a microphone, an amplifier, and one or more loudspeakers. PA systems of this type, often providing 50 to 200 watts of power, are often used in small venues such as school auditoriums, churches, and coffeehouse stages. Small PA systems may extend to an entire building, such as

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2478-421: 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. All PA systems have the potential for audio feedback , which occurs when

2537-581: The more popular DOD pedals are now available under the DigiTech name. This includes the Envelope Filter. In early 2010 Harman employee Tom Cram personally began a clandestine skunkworks project to revive DOD. This resulted in the prototypes for what would be the new DOD 250, 201, and an unidentified third red pedal. This skunkworks project was unknown to Harman and only became official after Cram showed his completed prototypes. Mr. Cram has subsequently become

2596-503: The 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 Associated Yacht and Power Boat Clubs of America. Seventy-two loudspeakers were strung in pairs at forty-foot (12 meter) intervals along the docks, spanning a total of one-half mile (800 meters) of grandstands. The system was used to announce race reports and descriptions, carry

2655-473: The predecessor to Harman International, Harman Kardon , in 1953. Both Harman and Kardon were engineers by training and had worked at the Bogen Company , which was a manufacturer of public address systems . They developed high-fidelity audio products together. Harman bought out his partner in 1956 and then expanded Harman Kardon. In the 1960s, Harman Kardon acquired other audio companies such as JBL . In

2714-411: The receiving end, either specialized intercom modules (sometimes known as IP speakers ) receive these network transmissions and reproduce the analog audio signal. These are small, specialized network appliances addressable by an IP address, just like any other computer on the network. A 2-Way Radio Wireless PA receiver and horn speaker is designed to facilitate the direct delivery of voice messages from

2773-519: The sounds of the original 250. In 2014 three more updated DOD pedals were released, the "BIFET Boost 410", and the "Envelope Filter 440", and the "Electro-Optical Compressor 280". The 410 features a new buffer on/off toggle and the 440 features an up/down voicing toggle, and the 280 circuit is untouched except for the addition of true bypass, LED, and modern PSU jack. All feature true bypass, blue LEDs, modern power jack, lighter aluminum chassis, two tone flat-black and metal-flake paint jobs. In early 2015

2832-578: The start of unwanted feedback and use a precise notch filter to lower the gain of the frequencies that are feeding back. Some automated feedback detectors require the user to "set" the feedback-prone frequencies by purposely increasing gain (during a sound check) until some feedback starts to occur. This process is often referred to as "a ring out" or "an EQ" of a room/venue. The device then retains these frequencies in its memory and it stands by ready to cut them. Some automated feedback prevention devices can detect and reduce new frequencies other than those found in

2891-558: The system into an electric wall socket. These may also be used for by people addressing smaller groups such as information sessions or team meetings. Battery-powered systems can be used by guides who are speaking to clients on walking tours. Public address systems consist of input sources (microphones, sound playback devices, etc.), amplifiers , control and monitoring equipment (e.g., LED indicator lights, VU meters, headphones), and loudspeakers . Usual input include microphones for speech or singing, direct inputs from musical instruments, and

2950-484: The systems used there. From the Ancient Greek era to the nineteenth century, before the invention of electric loudspeakers and amplifiers, megaphone cones were used by people speaking to a large audience, to make their voice project more to a large space or group. Megaphones are typically portable, usually hand-held, cone-shaped acoustic horns used to amplify a person's voice or other sounds and direct it towards

3009-533: The technology. A Long-Line Public Address (LLPA) system is any public address system with a distributed architecture, normally across a wide geographic area. Systems of this type are commonly found in the rail, light rail, and metro industries, and let announcements be triggered from one or several locations to the rest of the network over low bandwidth legacy copper, normally PSTN lines using DSL modems , or media such as optical fiber , or GSM-R , or IP-based networks. Rail systems typically have an interface with

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3068-431: The telephone system as the sole access point for the paging system, because the features are integrated. Many schools and other larger institutions are no longer using the large, bulky microphone PA systems and have switched to telephone system paging, as it can be accessed from many different points in the school. PA over IP refers to PA paging and intercom systems that use an Internet Protocol (IP) network, instead of

3127-651: The unit as well as technology license fees. The purchase did not include Bang & Olufsen's consumer-electronics business. Later that year, recognizing the increasing role of software and services in the markets it served, Harman expanded its capabilities around cloud, mobility and analytics with the acquisitions of Symphony Teleca , a software services company based in Mountain View, CA, and Redbend , an Israeli-based provider of software management technology for connected devices, and over-the-air (OTA) software and firmware upgrading services. In March 2016, Harman acquired

3186-456: Was Madrigal Audio Laboratories which includes Mark Levinson and Revel . In July 2011, Harman acquired MWM Acoustics. Harman expanded to include lighting in 2013 with the acquisition of Martin Professional . In June 2014, Harman completed the acquisition of AMX LLC . In March 2015, Harman acquired the automotive division of Bang & Olufsen for € 145 million ( US$ 156 million) for

3245-406: Was granted patents for the systems, which also incorporate control functionality. Using a WMT (GSM) network means that live announcements can be made to anywhere in the world where there is WMT connectivity. The patents cover all forms of WMT i.e., 2G, 3G, 4G ..... ××G. A UK company called Remvox Ltd (Remote Voice experience) has been appointed under license to develop and manufacture products based on

3304-536: Was made one week later, again supervised by Jensen and Pridham. On December 30, when Governor of California Hiram Johnson was too ill to give a speech in person, loudspeakers were installed at the Civic Auditorium in San Francisco , connected to Johnson's house some miles away by cable and a microphone, from where he delivered his speech. Jensen oversaw the governor using the microphone while Pridham operated

3363-564: Was part of his nationwide tour to promote the establishment of the League of Nations . It was held on September 9, 1919, at City Stadium . As with the San Francisco installation, Jensen supervised the microphone and Pridham the loudspeakers. Wilson spoke into two large horns mounted on his platform, which channelled his voice into the microphone. Similar systems were used in the following years by Warren G. Harding and Franklin D. Roosevelt . By

3422-539: Was succeeded by Dinesh Paliwal as chairman of the board. In April 2020 he was succeeded by Michael Mauser. Public address system A public address system (or PA system ) is an electronic system comprising microphones, amplifiers, loudspeakers, and related equipment. 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 that requires that an announcer, performer, etc. be sufficiently audible at

3481-521: Was used to transmitted news and entertainment programming to home and business subscribers in south-side Chicago, but this effort was short-lived. The company continued to market the enunciators for making announcements in establishments such as hospitals, department stores, factories, and railroad stations, although the Automatic Enunciator Company was dissolved in 1926. Peter Jensen and Edwin Pridham of Magnavox began experimenting with sound reproduction in

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