Megaphone

Last updated November 18, 2024

A megaphone, speaking trumpet, bullhorn, blowhorn, or loudhailer is usually a portable or hand-held, cone-shaped acoustic horn used to amplify a person's voice or other sounds and direct it in 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, and the sound waves radiate out the wide end. A megaphone increases the volume of sound by increasing the acoustic impedance seen by the vocal cords, matching the impedance of the vocal cords to the air, so that more sound power is radiated. It also serves to direct the sound waves in the direction the horn is pointing. It somewhat distorts the sound of the voice because the frequency response of the megaphone is greater at higher sound frequencies.

History

Before it became a megaphone, the bull horn or cow horn or steer horn was a signaling device or bugle used from antiquity.^[1]^[2]

The initial inventor of the speaking trumpet is a subject of historical controversy. There have been references to speakers in Ancient Greece (5th Century B.C.) wearing masks with cones protruding from the mouth in order to amplify their voices in theatres.^[3] Hellenic architects may have also consciously utilized acoustic physics in their design of theatre amphitheaters.

A drawing by Louis Nicolas (right) on page 14 of the Codex canadensis, circa 1675 to 1682, shows a Native American chief named Iscouakité using a megaphone made of birch bark. The text of the illustration says that he is addressing his soldiers through a birch bark tube.

Both Samuel Morland and Athanasius Kircher have been credited with inventing megaphones around the same time in the 17th century. Morland, in a work published in 1655, wrote about his experimentation with different horns. His largest megaphone consisted of over 20 feet of copper tube and could reportedly project a person's voice a mile and a half.^[4]

Twenty years earlier, Kircher described a device that could be used as both a megaphone and for "overhearing" people speaking outside a house. His coiled horn would be mounted into the side of a building, with a narrow end inside that could be either spoken into or listened to, and the wide mouth projecting through the outside wall.

Morland favored a straight, tube-shaped speaking device. Kircher's horn, on the other hand, utilized a "cochleate" design, where the horn was twisted and coiled to make it more compact.

A later, papier-mâché trumpet of special design was the Sengerphone.^[5]

Additionally, in ruins of Tiwanaku are stones around the central place with holes shaped in a megaphone's profile. Their purpose is today unknown, but as local guards can show, it is possible to amplify a human voice loud enough to hear it across a large area.

The term 'megaphone' was first associated with Thomas Edison's instrument 200 years later. In 1878, Edison developed a device similar to the speaking trumpet in hopes of benefiting the deaf and hard of hearing. His variation included three separate funnels lined up in a row. The two outer funnels, which were six feet and eight inches long, were made of paper and connected to a tube inserted in each ear. The middle funnel was similar to Morland's speaking trumpet, but had a larger slot to insert a user's mouth.^[6]

With Edison's megaphone, a low whisper could be heard a thousand feet away, while a normal tone of voice could be heard roughly two miles away. On the listening end, the receiver could hear a low whisper at a thousand feet away. However the apparatus was much too large to be portable, limiting its use. George Prescott wrote: "The principal drawback at present is the large size of the apparatus."

Prior to the invention of the electric microphone, early pop singers sang with a megaphone.

Since the 1960s, acoustic megaphones have generally been replaced by electric versions (below), although the cheap, light, rugged acoustic megaphone is still used in a few venues, like cheering at sporting events and cheerleading, and by lifeguards at pools and beaches where the moisture could damage the electronics of electric megaphones.

German soldier using a megaphone to command troops, 1930

A sailor using a megaphone to amplify the sound of a bugle to wake recruits at an American training camp in 1947

German lifeguard with megaphone, 1969

Austrian jazz singer using megaphone, 2007

Electric megaphone

(left) Woman using a small handheld electric megaphone at a demonstration in Portugal. (right) Electric megaphones use a type of horn loudspeaker called a reflex or reentrant horn. The sound waves travel in a zigzag path through concentric widening ducts (b, c, and d).

An electric megaphone is a handheld public address system, an electronic device that amplifies the human voice like an acoustic megaphone, using electric power. It consists of a microphone to convert soundwaves into an electrical audio signal, an amplifier powered by a battery to increase the power of the audio signal, and a loudspeaker to convert the audio signal to sound waves again. Although slightly heavier than acoustic megaphones, electric megaphones can amplify the voice to a higher level, to over 90 dB. They have replaced acoustic megaphones in most applications, and are generally used to address congregations of people wherever stationary public address systems are not available; at outdoor sporting events, movie sets, political rallies, and street demonstrations.

Although electronic public address systems have existed since vacuum tube amplifiers were developed in the early 1920s, vacuum tube versions were too heavy to be portable. Practical portable electric megaphones had to await the development of microelectronics which followed the invention of the transistor in 1947. In 1954, TOA Corporation developed the EM-202, the world's first transistorized megaphone.^[7]

Handheld versions are shaped generally like the old acoustic megaphone, with a microphone at one end and a horn speaker at the other, and a pistol grip on the side, with a trigger switch to turn it on. In use, the device is held up to the mouth, and the trigger is pressed to turn it on while speaking. Other larger versions hang from the shoulder on a strap, and have a separate handheld microphone on a cord to speak into, so users can address a crowd without the instrument obscuring their faces. A vast array of modern electric megaphones are available to purchase, and characteristics like power, weight, price, and the presence of alarms and shoulder straps all contribute to a consumer's choice.^[8]

The shape of the megaphone directly affects the range of projection; narrower horns compensate for lower power by concentrating sound more sharply than wide horns.

The EM-202 made by TOA Corp., the first transistorized handheld megaphone

Waist-slung megaphones with separate microphones

Man using megaphone with separate microphone

Impact on society

Portable megaphones are widely used for crowd management and mass communication. When needing to communicate information or directions to a large crowd of people in one place, an electric megaphone is valuable when other public address systems are not present.

Besides their practical implications, public address systems, including megaphones, also had a social impact. Public address systems helped promote women's participation in society. In events like the National Republican and Democratic Conventions of 1920, when electronic public address systems were first becoming popularized, women used these amplifying technologies during the roll call of participants.^[9] Later, portable electric megaphones extended this equalizing influence to outdoor events. Some protest leaders use electric megaphones to speak to an outdoor crowd or to other protesters.

As of the 2010s, cheerleading is one of the few fields that still uses acoustic megaphones. Cheerleaders at the University of Minnesota are credited with first using acoustic megaphones in routines in 1898. Since then, cheerleaders have relied heavily on acoustic megaphones during performances at sporting events. Generally, female cheerleaders would use pom poms while male cheerleaders, with loud booming voices, would project cheers through megaphones.^[10] Vocal projection is an important aspect for cheerleading, so experts recommend the use of acoustic megaphones not only to increase the volume of sound, but also to protect performers’ voices in the process.^[11]

For decades, film directors have used megaphones to communicate with their cast and crew on sets where it was hard to hear. The acoustic megaphone became an iconic clichéd symbol of a movie director, although modern directors use electric megaphones. A major contributor to this cliche was Cecil B. DeMille, director of epic movies like The Ten Commandments and The King of Kings. Many of his films were biblical epics set on vast outdoor sets that required communication with hundreds of extras.^[12]

The distinctive distorted sound of a human voice amplified by a megaphone is widely recognized, from its use in train and bus stations and sports arenas. Applied to music, it gives the sound of an antique acoustic gramophone record player. It has been used in radio advertisements and popular music to give retro and often humorous effects. A recorded voice or music can be processed to give it a "megaphone" sound effect without using an actual megaphone, by audio recording decks and software. In recording software like Logic Pro and Pro Tools, selecting certain filters and settings will produce an artificial sound almost indistinguishable from an electric megaphone.^[13]

Legal restrictions

Governments can pass laws restricting the use of electronically amplified megaphones. In the US the ability to use a megaphone in public can be restricted to certain decibel levels, time of day or banned in residential neighborhoods. However, under the First Amendment, the specific kinds of speech used with a megaphone cannot be restricted.^[14]

Related Research Articles

<span class="mw-page-title-main">Loudspeaker</span> Converts an electrical audio signal into a corresponding sound

A loudspeaker is a combination of one or more speaker drivers, an enclosure, and electrical connections. The speaker driver is an electroacoustic transducer that converts an electrical audio signal into a corresponding sound.

A microphone, colloquially called a mic, or mike, is a transducer that converts sound into an electrical signal. Microphones are used in many applications such as telephones, hearing aids, public address systems for concert halls and public events, motion picture production, live and recorded audio engineering, sound recording, two-way radios, megaphones, and radio and television broadcasting. They are also used in computers and other electronic devices, such as mobile phones, for recording sounds, speech recognition, VoIP, and other purposes, such as ultrasonic sensors or knock sensors.

An audio power amplifier amplifies low-power electronic audio signals, such as the signal from a radio receiver or an electric guitar pickup, to a level that is high enough for driving loudspeakers or headphones. Audio power amplifiers are found in all manner of sound systems including sound reinforcement, public address, home audio systems and musical instrument amplifiers like guitar amplifiers. It is the final electronic stage in a typical audio playback chain before the signal is sent to the loudspeakers.

Audio feedback is a positive feedback situation that may occur when an acoustic path exists between an audio output and its audio input. In this example, a signal received by the microphone is amplified and passed out of the loudspeaker. The sound from the loudspeaker can then be received by the microphone again, amplified further, and then passed out through the loudspeaker again. The frequency of the resulting howl is determined by resonance frequencies in the microphone, amplifier, and loudspeaker, the acoustics of the room, the directional pick-up and emission patterns of the microphone and loudspeaker, and the distance between them. The principles of audio feedback were first discovered by Danish scientist Søren Absalon Larsen, hence it is also known as the Larsen effect.

<span class="mw-page-title-main">Recording studio</span> Facility for sound recording

A recording studio is a specialized facility for recording and mixing of instrumental or vocal musical performances, spoken words, and other sounds. They range in size from a small in-home project studio large enough to record a single singer-guitarist, to a large building with space for a full orchestra of 100 or more musicians. Ideally, both the recording and monitoring spaces are specially designed by an acoustician or audio engineer to achieve optimum acoustic properties.

<span class="mw-page-title-main">Instrument amplifier</span> Amplifier with loudspeaker for use with musical instruments

An instrument amplifier is an electronic amplifier that converts the often barely audible or purely electronic signal of a musical instrument into a larger electronic signal to feed to a loudspeaker. An instrument amplifier is used with musical instruments such as an electric guitar, an electric bass, electric organ, electric piano, synthesizers and drum machine to convert the signal from the pickup or other sound source into an electronic signal that has enough power, produced by a power amplifier, to drive one or more loudspeaker that can be heard by the performers and audience.

<span class="mw-page-title-main">Guitar amplifier</span> Electronic amplifier for musical instruments

A guitar amplifier is an electronic device or system that strengthens the electrical signal from a pickup on an electric guitar, bass guitar, or acoustic guitar so that it can produce sound through one or more loudspeakers, which are typically housed in a wooden cabinet. A guitar amplifier may be a standalone wood or metal cabinet that contains only the power amplifier circuits, requiring the use of a separate speaker cabinet–or it may be a combo amplifier, which contains both the amplifier and one or more speakers in a wooden cabinet. There is a wide range of sizes and power ratings for guitar amplifiers, from small, lightweight practice amplifiers with a single 6-inch speaker and a 10-watt amp to heavy combo amps with four 10-inch or four 12-inch speakers and a 100-watt amplifier, which are loud enough to use in a nightclub or bar performance.

A public address 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 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.

A sound reinforcement system is the combination of microphones, signal processors, amplifiers, and loudspeakers in enclosures all controlled by a mixing console that makes live or pre-recorded sounds louder and may also distribute those sounds to a larger or more distant audience. In many situations, a sound reinforcement system is also used to enhance or alter the sound of the sources on the stage, typically by using electronic effects, such as reverb, as opposed to simply amplifying the sources unaltered.

A speaking tube or voicepipe is a device based on two cones connected by an air pipe through which speech can be transmitted over an extended distance.

An ear trumpet is a tubular or funnel-shaped device which collects sound waves and leads them into the ear. They are used as hearing aids, resulting in a strengthening of the sound energy impact to the eardrum and thus improved hearing for a deaf or hard-of-hearing individual. Ear trumpets were made of sheet metal, silver, wood, snail shells or animal horns. They have largely been replaced in wealthier areas of the world by modern hearing aid technology that is much smaller and less obtrusive, albeit more expensive.

The carbon microphone, also known as carbon button microphone, button microphone, or carbon transmitter, is a type of microphone, a transducer that converts sound to an electrical audio signal. It consists of two metal plates separated by granules of carbon. One plate is very thin and faces toward the speaking person, acting as a diaphragm. Sound waves striking the diaphragm cause it to vibrate, exerting a varying pressure on the granules, which in turn changes the electrical resistance between the plates. Higher pressure lowers the resistance as the granules are pushed closer together. A steady direct current is passed between the plates through the granules. The varying resistance results in a modulation of the current, creating a varying electric current that reproduces the varying pressure of the sound wave. In telephony, this undulating current is directly passed through the telephone wires to the central office. In public address systems it is amplified by an audio amplifier. The frequency response of most carbon microphones, however, is limited to a narrow range, and the device produces significant electrical noise.

A bass amplifier is a musical instrument electronic device that uses electrical power to make lower-pitched instruments such as the bass guitar or double bass loud enough to be heard by the performers and audience. Bass amps typically consist of a preamplifier, tone controls, a power amplifier and one or more loudspeakers ("drivers") in a cabinet.

Distortion and overdrive are forms of audio signal processing used to alter the sound of amplified electric musical instruments, usually by increasing their gain, producing a "fuzzy", "growling", or "gritty" tone. Distortion is most commonly used with the electric guitar, but may also be used with other electric instruments such as electric bass, electric piano, synthesizer and Hammond organ. Guitarists playing electric blues originally obtained an overdriven sound by turning up their vacuum tube-powered guitar amplifiers to high volumes, which caused the signal to distort. While overdriven tube amps are still used to obtain overdrive, especially in genres like blues and rockabilly, a number of other ways to produce distortion have been developed since the 1960s, such as distortion effect pedals. The growling tone of a distorted electric guitar is a key part of many genres, including blues and many rock music genres, notably hard rock, punk rock, hardcore punk, acid rock, grunge and heavy metal music, while the use of distorted bass has been essential in a genre of hip hop music and alternative hip hop known as "SoundCloud rap".

A guitar speaker is a loudspeaker – specifically the driver (transducer) part – designed for use in a combination guitar amplifier of an electric guitar, or for use in a guitar speaker cabinet. Typically these drivers produce only the frequency range relevant to electric guitars, which is similar to a regular woofer type driver, which is approximately 75 Hz — 5 kHz, or for electric bass speakers, down to 41 Hz for regular four-string basses or down to about 30 Hz for five-string instruments.

Orchestral enhancement is the technique of using orchestration techniques, architectural modifications, or electronic technologies to modify the sound, complexity, or color of a musical theatre, ballet or opera pit orchestra. Orchestral enhancements are used both to create new sounds and to add capabilities to existing orchestral ensembles.

A human microphone, also known as the people's microphone, is a means for delivering a speech to a large group of people, wherein persons gathered around the speaker repeat what the speaker says, thus "amplifying" the voice of the speaker without the need for amplification equipment.

The first hearing aid was created in the 17th century. The movement toward modern hearing aids began with the creation of the telephone, and the first electric hearing aid was created in 1898. By the late 20th century, the digital hearing aid was distributed to the public commercially. Some of the first hearing aids were external hearing aids. External hearing aids direct sounds in front of the ear and block all other noises. The apparatus would fit behind or in the ear.

<span class="mw-page-title-main">Keyboard amplifier</span>

A keyboard amplifier is a powered electronic amplifier and loudspeaker in a speaker cabinet used for the amplification of electronic keyboard instruments. Keyboard amplifiers are distinct from other types of amplification systems such as guitar amplifiers due to the particular challenges associated with making keyboards sound louder on stage; namely, to provide solid low-frequency sound reproduction for the deep basslines that keyboards can play and crisp high-frequency sound for the high-register notes. Another difference between keyboard amplifiers and guitar/bass amplifiers is that keyboard amps are usually designed with a relatively flat frequency response and low distortion. In contrast, many guitar and bass amp designers purposely make their amplifiers modify the frequency response, typically to "roll-off" very high frequencies, and most rock and blues guitar amps, and since the 1980s and 1990s, even many bass amps are designed to add distortion or overdrive to the instrument tone.

Phonurgia Nova is a 1673 work by the Jesuit scholar Athanasius Kircher. It is notable for being the first book ever dedicated entirely to the science of acoustics, and for containing the earliest description of an aeolian harp. It was dedicated to the Holy Roman Emperor Leopold I and printed in Kempten by Rudoph Dreherr.

References

↑ Baines, Anthony C (1984). "Cow Horn". In Sadie, Stanley (ed.). The New Grove Dictionary of Musical Instruments. Vol. 1. p. 511.
↑ Sadie, Stanley, ed. (1984). "Stierhorn". The New Grove Dictionary of Musical Instruments. Vol. 3. p. 455.
↑ Montgomery, Henry C. (1959). "Amplification and High Fidelity in the Greek Theater". The Classical Journal . 54 (6): 242–245. JSTOR 3294133.
↑ Mills, Mara. "When Mobile Communication Technologies Were New." Endeavour 33.4 (200111111: 141-47.
↑ "SENGERPHONE-Y by Len Mullenger". www.musicweb-international.com.
↑ Prescott, George B. Bell's Electric Speaking Telephone: Its Invention, Construction, Application, Modification, and History. New York: D. Appleton &, 1884.
↑ "TOA | From 2010 | TOA History". TOA Corporation.
↑ "Megaphone & Bullhorns". Archived from the original on September 1, 2012.
↑ Kramarae, Cheris. Technology and Women's Voices: Keeping in Touch. New York: Routledge & Kegan Paul, 1988.
↑ Hanson, Mary Ellen. Go! Fight! Win!: Cheerleading in American Culture. Bowling Green, OH: Bowling Green State University Popular, 1995.
↑ Carrier, Justin, and Donna McKay. Complete Cheerleading. Champaign, IL: Human Kinetics, 2006.
↑ "Cecil B. DeMille". IMDb.
↑ Savage, Jason. "The Megaphone Effect in Radio Ads". Houston Chronicle / Demand Media . Retrieved 2 September 2013.
↑ Bernstein, David E. You Can't Say That!: The Growing Threat to Civil Liberties from Antidiscrimination Laws (2003 ed.). Cato Institute. p. 31.

External links

"Controlling Public Protest: First Amendment Implications" An article about restrictions that may legally be imposed on public protests (including use of bullhorns), by Daniel L. Schofield, S.J.D., published in the November 1994 issue of the FBI's Law Enforcement Bulletin.

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[GroveCowhorn-1] Baines, Anthony C (1984). "Cow Horn". In Sadie, Stanley (ed.). The New Grove Dictionary of Musical Instruments. Vol. 1. p. 511.

[GroveStierhorn-2] Sadie, Stanley, ed. (1984). "Stierhorn". The New Grove Dictionary of Musical Instruments. Vol. 3. p. 455.

[3] Montgomery, Henry C. (1959). "Amplification and High Fidelity in the Greek Theater". The Classical Journal . 54 (6): 242–245. JSTOR 3294133.

[4] Mills, Mara. "When Mobile Communication Technologies Were New." Endeavour 33.4 (200111111: 141-47.

[5] "SENGERPHONE-Y by Len Mullenger". www.musicweb-international.com.

[6] Prescott, George B. Bell's Electric Speaking Telephone: Its Invention, Construction, Application, Modification, and History. New York: D. Appleton &, 1884.

[7] "TOA | From 2010 | TOA History". TOA Corporation.

[8] "Megaphone & Bullhorns". Archived from the original on September 1, 2012.

[9] Kramarae, Cheris. Technology and Women's Voices: Keeping in Touch. New York: Routledge & Kegan Paul, 1988.

[10] Hanson, Mary Ellen. Go! Fight! Win!: Cheerleading in American Culture. Bowling Green, OH: Bowling Green State University Popular, 1995.

[11] Carrier, Justin, and Donna McKay. Complete Cheerleading. Champaign, IL: Human Kinetics, 2006.

[12] "Cecil B. DeMille". IMDb.

[13] Savage, Jason. "The Megaphone Effect in Radio Ads". Houston Chronicle / Demand Media . Retrieved 2 September 2013.

[14] Bernstein, David E. You Can't Say That!: The Growing Threat to Civil Liberties from Antidiscrimination Laws (2003 ed.). Cato Institute. p. 31.

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