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95-469: Soundcraft first made its mark by manufacturing the Series 1, the first mixing console built into a flight-case. It was available with 12 or 16 input channels and 4 outputs—main stereo, plus a post-fader ‘echo’ send and pre-fader foldback. Each channel had four-band fixed-frequency EQ. The Series 1 also included a multi-pin connector that integrated with a multi-channel microphone snake to route signals from and to

190-435: A caveat for a version using a brass rod instead of the needle. Other minor variations and improvements were made to the liquid microphone by Majoranna, Chambers, Vanni, Sykes, and Elisha Gray, and one version was patented by Reginald Fessenden in 1903. These were the first working microphones, but they were not practical for commercial application. The famous first phone conversation between Bell and Watson took place using

285-713: A mic ( / m aɪ k / ), 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 . Several types of microphone are used today, which employ different methods to convert

380-563: A patent caveat for his telephonic device to the U.S. Patent Office in 1871, but there was no mention of electromagnetic transmission of vocal sound in his caveat. In 1876, Alexander Graham Bell was granted a patent for the electromagnetic transmission of vocal sound by undulatory electric current. Despite the longstanding general crediting of Bell with the accomplishment, the Italian Ministry of Cultural Heritage and Activities supported celebrations of Meucci's 200th birthday in 2008 using

475-403: A resonant circuit that modulates the frequency of the oscillator signal. Demodulation yields a low-noise audio frequency signal with a very low source impedance. The absence of a high bias voltage permits the use of a diaphragm with looser tension, which may be used to achieve wider frequency response due to higher compliance. The RF biasing process results in a lower electrical impedance capsule,

570-592: A 3.5 mm plug as usually used for stereo connections; the ring, instead of carrying the signal for a second channel, carries power. A valve microphone is a condenser microphone that uses a vacuum tube (valve) amplifier . They remain popular with enthusiasts of tube sound . The dynamic microphone (also known as the moving-coil microphone ) works via electromagnetic induction . They are robust, relatively inexpensive and resistant to moisture. This, coupled with their potentially high gain before feedback , makes them popular for on-stage use. Dynamic microphones use

665-647: A Spanish province, where Meucci accepted a job at what was then called the Teatro Tacón in Havana (at the time, the greatest theater in the Americas). In Havana he constructed a system for water purification and reconstructed the Gran Teatro. In 1848 his contract with the governor expired. Meucci was asked by a friend's doctors to work on Franz Anton Mesmer 's therapy system on patients with rheumatism . In 1849, he developed

760-452: A button microphone), uses a capsule or button containing carbon granules pressed between two metal plates like the Berliner and Edison microphones. A voltage is applied across the metal plates, causing a small current to flow through the carbon. One of the plates, the diaphragm, vibrates in sympathy with incident sound waves, applying a varying pressure to the carbon. The changing pressure deforms

855-441: A diaphragm that is at least partially open on both sides. The pressure difference between the two sides produces its directional characteristics. Other elements such as the external shape of the microphone and external devices such as interference tubes can also alter a microphone's directional response. A pure pressure-gradient microphone is equally sensitive to sounds arriving from front or back but insensitive to sounds arriving from

950-435: A high-quality audio signal and are now the popular choice in laboratory and recording studio applications. The inherent suitability of this technology is due to the very small mass that must be moved by the incident sound wave compared to other microphone types that require the sound wave to do more work. Condenser microphones require a power source, provided either via microphone inputs on equipment as phantom power or from

1045-492: A laser source travels through an optical fiber to illuminate the surface of a reflective diaphragm. Sound vibrations of the diaphragm modulate the intensity of light reflecting off the diaphragm in a specific direction. The modulated light is then transmitted over a second optical fiber to a photodetector, which transforms the intensity-modulated light into analog or digital audio for transmission or recording. Fiber-optic microphones possess high dynamic and frequency range, similar to

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1140-539: A laser-photocell pair with a moving stream of smoke or vapor in the laser beam's path. Sound pressure waves cause disturbances in the smoke that in turn cause variations in the amount of laser light reaching the photodetector. A prototype of the device was demonstrated at the 127th Audio Engineering Society convention in New York City from 9 through October 12, 2009. Early microphones did not produce intelligible speech, until Alexander Graham Bell made improvements including

1235-453: A liquid microphone. The MEMS (microelectromechanical systems) microphone is also called a microphone chip or silicon microphone. A pressure-sensitive diaphragm is etched directly into a silicon wafer by MEMS processing techniques and is usually accompanied with an integrated preamplifier. Most MEMS microphones are variants of the condenser microphone design. Digital MEMS microphones have built-in analog-to-digital converter (ADC) circuits on

1330-464: A popular method of using electric shocks to treat illness and subsequently experimentally developed a device through which one could hear inarticulate human voice. He called this device "telegrafo parlante" (talking telegraph). In 1850, the third renewal of Meucci's contract with Don Francisco Martí y Torrens expired, and his friendship with General Giuseppe Garibaldi made him a suspect citizen in Cuba. On

1425-457: A preamplifier and, therefore, do require phantom power, and circuits of modern passive ribbon microphones (i.e. those without the aforementioned preamplifier) are specifically designed to resist damage to the ribbon and transformer by phantom power. Also there are new ribbon materials available that are immune to wind blasts and phantom power. The carbon microphone was the earliest type of microphone. The carbon button microphone (or sometimes just

1520-414: A small battery. Power is necessary for establishing the capacitor plate voltage and is also needed to power the microphone electronics. Condenser microphones are also available with two diaphragms that can be electrically connected to provide a range of polar patterns , such as cardioid, omnidirectional, and figure-eight. It is also possible to vary the pattern continuously with some microphones, for example,

1615-402: A sound conductor, which is also an electrical conductor, as a means of communication by sound between distant points. Fourth. The same in combination with provisions for electrically insulating the sending and receiving parties. Fifth. The mouthpiece or speaking utensil in combination with an electrically insulating conductor. Sixth. The ear utensils or receiving vessels adapted to apply upon

1710-445: A spirale che lo avvolge. Vibrando, il diaframma altera la corrente del magnete. Queste alterazioni di corrente, trasmesse all'altro capo del filo, imprimono analoghe vibrazioni al diaframma ricevente e riproducono la parola. Translated: It consists of a vibrating diaphragm and a magnet electrified by a spiral wire that wraps around it. The vibrating diaphragm alters the current of the magnet. These alterations of current, transmitted to

1805-598: A static charge is embedded in an electret by the alignment of the static charges in the material, much the way a permanent magnet is made by aligning the magnetic domains in a piece of iron. Due to their good performance and ease of manufacture, hence low cost, the vast majority of microphones made today are electret microphones; a semiconductor manufacturer estimates annual production at over one billion units. They are used in many applications, from high-quality recording and lavalier (lapel mic) use to built-in microphones in small sound recording devices and telephones. Prior to

1900-432: A thin, usually corrugated metal ribbon suspended in a magnetic field. The ribbon is electrically connected to the microphone's output, and its vibration within the magnetic field generates the electrical signal. Ribbon microphones are similar to moving coil microphones in the sense that both produce sound by means of magnetic induction. Basic ribbon microphones detect sound in a bi-directional (also called figure-eight, as in

1995-575: A useful by-product of which is that RF condenser microphones can be operated in damp weather conditions that could create problems in DC-biased microphones with contaminated insulating surfaces. The Sennheiser MKH series of microphones use the RF biasing technique. A covert, remotely energized application of the same physical principle called the Thing was devised by Soviet Russian inventor Leon Theremin and used to bug

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2090-424: A variable-resistance microphone/transmitter. Bell's liquid transmitter consisted of a metal cup filled with water with a small amount of sulfuric acid added. A sound wave caused the diaphragm to move, forcing a needle to move up and down in the water. The electrical resistance between the wire and the cup was then inversely proportional to the size of the water meniscus around the submerged needle. Elisha Gray filed

2185-476: A very limited frequency response range but are very robust devices. The Boudet microphone, which used relatively large carbon balls, was similar to the granule carbon button microphones. Unlike other microphone types, the carbon microphone can also be used as a type of amplifier, using a small amount of sound energy to control a larger amount of electrical energy. Carbon microphones found use as early telephone repeaters , making long-distance phone calls possible in

2280-635: A very poor sound quality. The first microphone that enabled proper voice telephony was the (loose-contact) carbon microphone . This was independently developed by David Edward Hughes in England and Emile Berliner and Thomas Edison in the US. Although Edison was awarded the first patent in mid-1877 (after a long legal dispute), Hughes had demonstrated his working device in front of many witnesses some years earlier, and most historians credit him with its invention. The Berliner microphone found commercial success through

2375-413: A voltage when subjected to pressure—to convert vibrations into an electrical signal. An example of this is potassium sodium tartrate , which is a piezoelectric crystal that works as a transducer, both as a microphone and as a slimline loudspeaker component. Crystal microphones were once commonly supplied with vacuum tube (valve) equipment, such as domestic tape recorders. Their high output impedance matched

2470-421: Is a function of frequency. The body of the microphone is not infinitely small and, as a consequence, it tends to get in its own way with respect to sounds arriving from the rear, causing a slight flattening of the polar response. This flattening increases as the diameter of the microphone (assuming it's cylindrical) reaches the wavelength of the frequency in question. Therefore, the smallest diameter microphone gives

2565-403: Is aimed at the surface of a window or other plane surface that is affected by sound. The vibrations of this surface change the angle at which the beam is reflected, and the motion of the laser spot from the returning beam is detected and converted to an audio signal. In a more robust and expensive implementation, the returned light is split and fed to an interferometer , which detects movement of

2660-548: Is at least one practical application that exploits those weaknesses: the use of a medium-size woofer placed closely in front of a "kick drum" ( bass drum ) in a drum set to act as a microphone. A commercial product example is the Yamaha Subkick, a 6.5-inch (170 mm) woofer shock-mounted into a 10" drum shell used in front of kick drums. Since a relatively massive membrane is unable to transduce high frequencies while being capable of tolerating strong low-frequency transients,

2755-399: Is practically constant and the voltage across the capacitor changes instantaneously to reflect the change in capacitance. The voltage across the capacitor varies above and below the bias voltage. The voltage difference between the bias and the capacitor is seen across the series resistor. The voltage across the resistor is amplified for performance or recording. In most cases, the electronics in

2850-505: Is to bring distinctly to the hearing the word of the person at the opposite end of the telegraph. To call attention, the party at the other end of the line may be warned by an electric telegraph signal, or a series of them. The apparatus for this purpose, and the skill in operating it, need be much less than for the ordinary telegraphing. When my sound telegraph is in operation, the parties should remain alone in their respective rooms, and every practicable precaution should be taken to have

2945-441: Is to sounds arriving at different angles about its central axis. The polar patterns illustrated above represent the locus of points in polar coordinates that produce the same signal level output in the microphone if a given sound pressure level (SPL) is generated from that point. How the physical body of the microphone is oriented relative to the diagrams depends on the microphone design. For large-membrane microphones such as in

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3040-692: The Italian Republic ), on 13 April 1808, as the first of nine children to Amatis Meucci and Domenica Pepi. Amatis was at times a government clerk and a member of the local police, and Domenica was principally a homemaker. Four of Meucci's siblings did not survive childhood. In November 1821, at the age of 13, he was admitted to Florence Academy of Fine Arts as its youngest student, where he studied chemical and mechanical engineering . He ceased full-time studies two years later due to insufficient funds, but continued studying part-time after obtaining employment as an assistant gatekeeper and customs official for

3135-471: The Røde NT2000 or CAD M179. There are two main categories of condenser microphones, depending on the method of extracting the audio signal from the transducer: DC-biased microphones, and radio frequency (RF) or high frequency (HF) condenser microphones. With a DC-biased condenser microphone , the plates are biased with a fixed charge ( Q ). The voltage maintained across the capacitor plates changes with

3230-643: The Teatro della Pergola in Florence as a stage technician, assisting Artemio Canovetti. In 1834 Meucci constructed a type of acoustic telephone to communicate between the stage and control room at the Teatro of Pergola. This telephone was constructed on the principles of pipe-telephones used on ships and still functions. He married costume designer Esterre Mochi, who was employed in the same theatre, on 7 August 1834. In October 1835, Meucci and his wife emigrated to Cuba , then

3325-657: The Westfield , Meucci's financial and health state was so bad that his wife sold his drawings and devices to a second-hand dealer to raise money. On 12 December 1871 Meucci set up an agreement with Angelo Zilio Grandi (Secretary of the Italian Consulate in New York), Angelo Antonio Tremeschin ( entrepreneur ), Sereno G.P. Breguglia Tremeschin (businessman), in order to constitute the Telettrofono Company. The constitution

3420-405: The diagram below) pattern because the ribbon is open on both sides. Also, because the ribbon has much less mass it responds to the air velocity rather than the sound pressure . Though the symmetrical front and rear pickup can be a nuisance in normal stereo recording, the high side rejection can be used to advantage by positioning a ribbon microphone horizontally, for example above cymbals, so that

3515-406: The 2010s, there has been increased interest and research into making piezoelectric MEMS microphones which are a significant architectural and material change from existing condenser style MEMS designs. In a plasma microphone, a plasma arc of ionized gas is used. The sound waves cause variations in the pressure around the plasma in turn causing variations in temperature which alter the conductance of

3610-509: The County of Richmond and State of New York, respectfully represents: That he has made certain improvements in Sound Telegraphs, ... The following is a description of the invention, sufficiently in detail for the purposes of this caveat. I employ the well-known conducting effect of continuous metallic conductors as a medium for sound, and increases the effect by electrically insulating both

3705-458: The English physicist Robert Hooke was the first to experiment with a medium other than air with the invention of the " lovers' telephone " made of stretched wire with a cup attached at each end. In 1856, Italian inventor Antonio Meucci developed a dynamic microphone based on the generation of electric current by moving a coil of wire to various depths in a magnetic field. This method of modulation

3800-532: The Florentine government. In May 1825, because of the celebrations for the childbirth of Marie Anna of Saxony , wife of Leopold II, Grand Duke of Tuscany , Meucci conceived a powerful propellant mixture for flares. The fireworks went out of his control, causing damages and injuries in the celebration's square. Meucci was arrested and suspected of conspiracy against the Grand Duchy. Meucci later became employed at

3895-507: The Oktava (pictured above), the upward direction in the polar diagram is usually perpendicular to the microphone body, commonly known as "side fire" or "side address". For small diaphragm microphones such as the Shure (also pictured above), it usually extends from the axis of the microphone commonly known as "end fire" or "top/end address". Some microphone designs combine several principles in creating

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3990-597: The US Ambassador's residence in Moscow between 1945 and 1952. An electret microphone is a type of condenser microphone invented by Gerhard Sessler and Jim West at Bell laboratories in 1962. The externally applied charge used for a conventional condenser microphone is replaced by a permanent charge in an electret material. An electret is a ferroelectric material that has been permanently electrically charged or polarized . The name comes from electrostatic and magnet ;

4085-414: The air pressure variations of a sound wave to an electrical signal. The most common are the dynamic microphone , which uses a coil of wire suspended in a magnetic field; the condenser microphone , which uses the vibrating diaphragm as a capacitor plate; and the contact microphone , which uses a crystal of piezoelectric material. Microphones typically need to be connected to a preamplifier before

4180-619: The best high fidelity conventional microphones. Fiber-optic microphones do not react to or influence any electrical, magnetic, electrostatic or radioactive fields (this is called EMI/RFI immunity). The fiber-optic microphone design is therefore ideal for use in areas where conventional microphones are ineffective or dangerous, such as inside industrial turbines or in magnetic resonance imaging (MRI) equipment environments. Fiber-optic microphones are robust, resistant to environmental changes in heat and moisture, and can be produced for any directionality or impedance matching . The distance between

4275-472: The best omnidirectional characteristics at high frequencies. The wavelength of sound at 10 kHz is 1.4" (3.5 cm). The smallest measuring microphones are often 1/4" (6 mm) in diameter, which practically eliminates directionality even up to the highest frequencies. Omnidirectional microphones, unlike cardioids, do not employ resonant cavities as delays, and so can be considered the "purest" microphones in terms of low coloration; they add very little to

4370-407: The capsule (around 5 to 100  pF ) and the value of the bias resistor (100  MΩ to tens of GΩ) form a filter that is high-pass for the audio signal, and low-pass for the bias voltage. Note that the time constant of an RC circuit equals the product of the resistance and capacitance. Within the time frame of the capacitance change (as much as 50 ms at 20 Hz audio signal), the charge

4465-593: The classic British sound. The Series 2 launched as a four-bus console, and was later available in an eight-bus version. It was initially offered in 12 and 16 channel versions, and a 24 channel version was later added. The design used a semi-modular approach with individual channels in separate modules. The master section was made up of echo return, group output, cue master and monitoring modules. The input channels were available in fixed-frequency EQ standard channel and swept EQ versions. The swept EQ version also allowed switching between microphone input and line input, which

4560-568: The conductor and the parties who are communicating. It forms a Speaking Telegraph, without the necessity for any hollow tube. I claim that a portion or the whole of the effect may also be realized by a corresponding arrangement with a metallic tube. I believe that some metals will serve better than others, but propose to try all kinds of metals. The system on which I propose to operate and calculate consists in isolating two persons, separated at considerable distance from each other, by placing them upon glass insulators; employing glass, for example, at

4655-425: The desired polar pattern. This ranges from shielding (meaning diffraction/dissipation/absorption) by the housing itself to electronically combining dual membranes. An omnidirectional (or nondirectional) microphone's response is generally considered to be a perfect sphere in three dimensions. In the real world, this is not the case. As with directional microphones, the polar pattern for an "omnidirectional" microphone

4750-490: The distance between the plates. Because the capacitance of the plates is inversely proportional to the distance between them, the vibrations produce changes in capacitance. These changes in capacitance are used to measure the audio signal . The assembly of fixed and movable plates is called an element or capsule . Condenser microphones span the range from telephone mouthpieces through inexpensive karaoke microphones to high-fidelity recording microphones. They generally produce

4845-486: The effective dynamic range of ribbon microphones at low frequencies. Protective wind screens can reduce the danger of damaging a vintage ribbon, and also reduce plosive artifacts in the recording. Properly designed wind screens produce negligible treble attenuation. In common with other classes of dynamic microphone, ribbon microphones do not require phantom power; in fact, this voltage can damage some older ribbon microphones. Some new modern ribbon microphone designs incorporate

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4940-466: The era before vacuum tubes. Called a Brown's relay, these repeaters worked by mechanically coupling a magnetic telephone receiver to a carbon microphone: the faint signal from the receiver was transferred to the microphone, where it modulated a stronger electric current, producing a stronger electrical signal to send down the line. A crystal microphone or piezo microphone uses the phenomenon of piezoelectricity —the ability of some materials to produce

5035-420: The expenses of his experiments. Their close working friendship continued until 1867. In August 1870 Meucci reportedly was able to capture a transmission of articulated human voice at the distance of a mile by using a copper plate as a conductor, insulated by cotton. He called this device the "telettrofono". While he was recovering from injuries that befell him in a boiler explosion aboard a Staten Island ferry ,

5130-422: The foot of the chair or bench on which each sits, and putting them in communication by means of a telegraph wire. I believe it preferable to have the wire of larger area than that ordinarily employed in the electric telegraph, but will experiment on this. Each of these persons holds to his mouth an instrument analogous to a speaking trumpet, in which the word may easily be pronounced, and the sound concentrated upon

5225-736: The free electrical communication with the ground. Or these conditions may possibly be reversed and still operate with some success. Both the conductors or utensils for mouth and ears should be, in fact I must say must be, metallic, and be so conditioned as to be good conductors of electricity. I claim as my invention, and desire to have considered as such, for all the purposes of this Caveat, The new invention herein set forth in all its details, combinations, and sub-combinations. And more especially, I claim First. A continuous sound conductor electrically insulated. Second. The same adapted for telegraphing by sound or for conversation between distant parties electrically insulated. Third. The employment of

5320-413: The granules, causing the contact area between each pair of adjacent granules to change, and this causes the electrical resistance of the mass of granules to change. The changes in resistance cause a corresponding change in the current flowing through the microphone, producing the electrical signal. Carbon microphones were once commonly used in telephones; they have extremely low-quality sound reproduction and

5415-770: The high input impedance (typically about 10 MΩ) of the vacuum tube input stage well. They were difficult to match to early transistor equipment and were quickly supplanted by dynamic microphones for a time, and later small electret condenser devices. The high impedance of the crystal microphone made it very susceptible to handling noise, both from the microphone itself and from the connecting cable. Piezoelectric transducers are often used as contact microphones to amplify sound from acoustic musical instruments, to sense drum hits, for triggering electronic samples, and to record sound in challenging environments, such as underwater under high pressure. Saddle-mounted pickups on acoustic guitars are generally piezoelectric devices that contact

5510-513: The internal baffle, allowing the selection of several response patterns ranging from "figure-eight" to "unidirectional". Such older ribbon microphones, some of which still provide high-quality sound reproduction, were once valued for this reason, but a good low-frequency response could be obtained only when the ribbon was suspended very loosely, which made them relatively fragile. Modern ribbon materials, including new nanomaterials , have now been introduced that eliminate those concerns and even improve

5605-423: The microphone itself contribute no voltage gain as the voltage differential is quite significant, up to several volts for high sound levels. RF condenser microphones use a comparatively low RF voltage, generated by a low-noise oscillator. The signal from the oscillator may either be amplitude modulated by the capacitance changes produced by the sound waves moving the capsule diaphragm, or the capsule may be part of

5700-489: The microphone's light source and its photodetector may be up to several kilometers without need for any preamplifier or another electrical device, making fiber-optic microphones suitable for industrial and surveillance acoustic monitoring. Fiber-optic microphones are used in very specific application areas such as for infrasound monitoring and noise cancellation . They have proven especially useful in medical applications, such as allowing radiologists, staff and patients within

5795-503: The next breakthrough with the first condenser microphone . In 1923, the first practical moving coil microphone was built. The Marconi-Sykes magnetophone, developed by Captain H. J. Round , became the standard for BBC studios in London. This was improved in 1930 by Alan Blumlein and Herbert Holman who released the HB1A and was the best standard of the day. Also in 1923, the ribbon microphone

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5890-452: The original sound. Being pressure-sensitive they can also have a very flat low-frequency response down to 20 Hz or below. Pressure-sensitive microphones also respond much less to wind noise and plosives than directional (velocity sensitive) microphones. Antonio Meucci Antonio Santi Giuseppe Meucci ( / m eɪ ˈ uː tʃ i / may- OO -chee , Italian: [anˈtɔːnjo meˈuttʃi] ; 13 April 1808 – 18 October 1889)

5985-410: The other end of the wire, create analogous vibrations of the receiving diaphragm and reproduce the word. Meucci devised an electromagnetic telephone as a way of connecting his second-floor bedroom to his basement laboratory, and thus being able to communicate with his wife. Between 1856 and 1870, Meucci developed more than 30 different kinds of telephones on the basis of this prototype. A postage stamp

6080-533: The other hand, the fame reached by Samuel F. B. Morse in the United States encouraged Meucci to make his living through inventions. On 13 April 1850, Meucci and his wife emigrated to the United States, taking with them approximately 26,000 pesos fuertes in savings (approximately $ 500,000 in 2010 dollars), and settled in the Clifton area of Staten Island , New York , New York . The Meuccis would live there for

6175-495: The plasma. These variations in conductance can be picked up as variations superimposed on the electrical supply to the plasma. This is an experimental form of microphone. A loudspeaker, a transducer that turns an electrical signal into sound waves, is the functional opposite of a microphone. Since a conventional speaker is similar in construction to a dynamic microphone (with a diaphragm, coil and magnet), speakers can actually work "in reverse" as microphones. Reciprocity applies, so

6270-468: The powerful and noisy magnetic field to converse normally, inside the MRI suites as well as in remote control rooms. Other uses include industrial equipment monitoring and audio calibration and measurement, high-fidelity recording and law enforcement. Laser microphones are often portrayed in movies as spy gadgets because they can be used to pick up sound at a distance from the microphone equipment. A laser beam

6365-415: The principal sound input to the principal axis (end- or side-address) of the microphone are used to describe the microphone. The condenser microphone , invented at Western Electric in 1916 by E. C. Wente, is also called a capacitor microphone or electrostatic microphone —capacitors were historically called condensers. The diaphragm acts as one plate of a capacitor, and audio vibrations produce changes in

6460-462: The principles of electromagnetic voice transmission for many years and was able to transmit his voice through wires in 1856. He installed a telephone-like device within his house in order to communicate with his wife, who was ill at the time. Some of Meucci's notes written in 1857 describe the basic principle of electromagnetic voice transmission or in other words, the telephone: Consiste in un diaframma vibrante e in un magnete elettrizzato da un filo

6555-474: The proliferation of MEMS microphones, nearly all cell-phone, computer, PDA and headset microphones were electret types. Unlike other capacitor microphones, they require no polarizing voltage, but often contain an integrated preamplifier that does require power. This preamplifier is frequently phantom powered in sound reinforcement and studio applications. Monophonic microphones designed for personal computers (PCs), sometimes called multimedia microphones, use

6650-451: The rear lobe picks up sound only from the cymbals. Crossed figure 8, or Blumlein pair , stereo recording is gaining in popularity, and the figure-eight response of a ribbon microphone is ideal for that application. Other directional patterns are produced by enclosing one side of the ribbon in an acoustic trap or baffle, allowing sound to reach only one side. The classic RCA Type 77-DX microphone has several externally adjustable positions of

6745-821: The remainder of their lives. On Staten Island he helped several countrymen committed to the Italian unification movement and who had escaped political persecution. Meucci invested the substantial capital he had earned in Cuba into a tallow candle factory (the first of its kind in the Americas) employing several Italian exiles. For two years Meucci hosted friends at his cottage, including General Giuseppe Garibaldi , and Colonel Paolo Bovi Campeggi, who arrived in New York two months after Meucci. They worked in Meucci's factory. In 1854, Meucci's wife Esterre became an invalid due to rheumatoid arthritis . Meucci continued his experiments. Meucci studied

6840-461: The resulting microphone has the same impairments as a single-driver loudspeaker: limited low- and high-end frequency response, poorly controlled directivity , and low sensitivity . In practical use, speakers are sometimes used as microphones in applications where high bandwidth and sensitivity are not needed such as intercoms , walkie-talkies or video game voice chat peripherals, or when conventional microphones are in short supply. However, there

6935-498: The same CMOS chip making the chip a digital microphone and so more readily integrated with modern digital products. Major manufacturers producing MEMS silicon microphones are Wolfson Microelectronics (WM7xxx) now Cirrus Logic, InvenSense (product line sold by Analog Devices ), Akustica (AKU200x), Infineon (SMM310 product), Knowles Electronics, Memstech (MSMx), NXP Semiconductors (division bought by Knowles ), Sonion MEMS, Vesper, AAC Acoustic Technologies, and Omron. More recently, since

7030-436: The same dynamic principle as in a loudspeaker , only reversed. A small movable induction coil , positioned in the magnetic field of a permanent magnet, is attached to the diaphragm. When sound enters through the windscreen of the microphone, the sound wave moves the diaphragm which moves the coil in the magnetic field, producing a varying voltage across the coil through electromagnetic induction. Ribbon microphones use

7125-538: The side because sound arriving at the front and back at the same time creates no gradient between the two. The characteristic directional pattern of a pure pressure-gradient microphone is like a figure-8. Other polar patterns are derived by creating a capsule that combines these two effects in different ways. The cardioid, for instance, features a partially closed backside, so its response is a combination of pressure and pressure-gradient characteristics. A microphone's directionality or polar pattern indicates how sensitive it

7220-403: The signal can be recorded or reproduced . In order to speak to larger groups of people, a need arose to increase the volume of the human voice. The earliest devices used to achieve this were acoustic megaphones. Some of the first examples, from fifth-century-BC Greece, were theater masks with horn-shaped mouth openings that acoustically amplified the voice of actors in amphitheaters . In 1665,

7315-438: The speaker is often ideal for picking up the kick drum while reducing bleed from the nearby cymbals and snare drums. The inner elements of a microphone are the primary source of differences in directivity. A pressure microphone uses a diaphragm between a fixed internal volume of air and the environment and responds uniformly to pressure from all directions, so it is said to be omnidirectional. A pressure-gradient microphone uses

7410-474: The stage from a mix position in the audience. The Series 1S was introduced in 1975 as an upgraded Series 1. The Series 1S introduced the classic Soundcraft four-band EQ with two sweepable mid-range sections. In addition to The Series 1S added a second foldback send and was available in a 20 channel version. In 1975, Soundcraft introduced the Series 2 console as a live and recording console. The Series 2 began to build Soundcraft's reputation for quality desks with

7505-479: The strings passing over the saddle. This type of microphone is different from magnetic coil pickups commonly visible on typical electric guitars , which use magnetic induction, rather than mechanical coupling, to pick up vibration. A fiber-optic microphone converts acoustic waves into electrical signals by sensing changes in light intensity, instead of sensing changes in capacitance or magnetic fields as with conventional microphones. During operation, light from

7600-423: The surface by changes in the optical path length of the reflected beam. The former implementation is a tabletop experiment; the latter requires an extremely stable laser and precise optics. A new type of laser microphone is a device that uses a laser beam and smoke or vapor to detect sound vibrations in free air. On August 25, 2009, U.S. patent 7,580,533 issued for a Particulate Flow Detection Microphone based on

7695-423: The surroundings perfectly quiet. The closed mouth utensil or trumpet, and the enclosing the persons also in a room alone, both tend to prevent undue publicity to the communication. I think it will be easy, by these means, to prevent the communication being understood by any but the proper persons. It may be found practicable to work with the person sending the message insulated, and with the person receiving it, in

7790-471: The title "Inventore del telefono" (Inventor of the telephone). The U.S. House of Representatives in a resolution in 2002 also acknowledged Meucci's work in the invention of the telephone, although the U.S. Senate did not join the resolution and the interpretation of the resolution is disputed. Meucci was born at Via dei Serragli 44 in the San Frediano borough of Florence , First French Empire (now in

7885-550: The use by Alexander Graham Bell for his telephone and Berliner became employed by Bell. The carbon microphone was critical in the development of telephony, broadcasting and the recording industries. Thomas Edison refined the carbon microphone into his carbon-button transmitter of 1886. This microphone was employed at the first radio broadcast ever, a performance at the New York Metropolitan Opera House in 1910. In 1916, E.C. Wente of Western Electric developed

7980-403: The vibrations in the air, according to the capacitance equation (C = Q ⁄ V ), where Q = charge in coulombs , C = capacitance in farads and V = potential difference in volts . A nearly constant charge is maintained on the capacitor. As the capacitance changes, the charge across the capacitor does change very slightly, but at audible frequencies it is sensibly constant. The capacitance of

8075-405: The wire. Another instrument is also applied to the ears, in order to receive the voice of the opposite party. All these, to wit, the mouth utensil and the ear instruments, communicate to the wire at a short distance from the persons. The ear utensils being of a convex form, like a clock glass, enclose the whole exterior part of the ear, and make it easy and comfortable for the operator. The object

8170-462: The word." In 1861, German inventor Johann Philipp Reis built an early sound transmitter (the " Reis telephone ") that used a metallic strip attached to a vibrating membrane that would produce intermittent current. Better results were achieved in 1876 with the " liquid transmitter " design in early telephones from Alexander Graham Bell and Elisha Gray – the diaphragm was attached to a conductive rod in an acid solution. These systems, however, gave

8265-641: Was a demand for high-fidelity microphones and greater directionality. Electro-Voice responded with their Academy Award -winning shotgun microphone in 1963. During the second half of the 20th century, development advanced quickly with the Shure Brothers bringing out the SM58 and SM57 . Microphones are categorized by their transducer principle (condenser, dynamic, etc.) and by their directional characteristics (omni, cardioid, etc.). Sometimes other characteristics such as diaphragm size, intended use or orientation of

8360-428: Was also the most enduring method for the technology of the telephone as well. Speaking of his device, Meucci wrote in 1857, "It consists of a vibrating diaphragm and an electrified magnet with a spiral wire that wraps around it. The vibrating diaphragm alters the current of the magnet. These alterations of current, transmitted to the other end of the wire, create analogous vibrations of the receiving diaphragm and reproduce

8455-408: Was an Italian inventor and an associate of Giuseppe Garibaldi , a major political figure in the history of Italy. Meucci is best known for developing a voice-communication apparatus that several sources credit as the first telephone . Meucci set up a form of voice-communication link in his Staten Island , New York , home that connected the second-floor bedroom to his laboratory. He submitted

8550-502: Was auctioned. The purchaser allowed the Meuccis to live in the cottage without paying rent, but Meucci's private finances dwindled and he soon had to live on public funds and by depending on his friends. As mentioned in William J. Wallace's ruling, during the years 1859–1861, Meucci was in close business and social relations with William E. Ryder, who invested money in Meucci's inventions and paid

8645-439: Was forced to unsuccessfully seek funds from rich Italian families. In 1860, he asked his friend Enrico Bandelari to look for Italian capitalists willing to finance his project. However, military expeditions led by Garibaldi, in what was about to become Italy, had made the geopolitical situation too unstable for anybody to invest. At the same time, Meucci was led to poverty by some fraudulent debtors. On 13 November 1861 his cottage

8740-399: Was introduced, another electromagnetic type, believed to have been developed by Harry F. Olson , who applied the concept used in a ribbon speaker to making a microphone. Over the years these microphones were developed by several companies, most notably RCA that made large advancements in pattern control, to give the microphone directionality. With television and film technology booming there

8835-557: Was notarized by Angelo Bertolino, a Notary Public of New York. Although their society funded him with $ 20, only $ 15 was needed to file for a full patent application. The caveat his lawyer submitted to the US Patent Office on 28 December 1871 was numbered 3335 and titled "Sound Telegraph". The following is the text of Meucci's caveat, omitting legal details of the Petition, Oath, and Jurat: The petition of Antonio Meucci, of Clifton, in

8930-555: Was produced in Italy in 2003 that featured a portrait of Meucci. Around 1858, artist Nestore Corradi sketched Meucci's communication concept. His drawing was used to accompany the stamp in a commemorative publication of the Italian Postal and Telegraph Society. Meucci intended to develop his prototype but did not have the financial means to keep his company afloat in order to finance his invention. His candle factory went bankrupt and Meucci

9025-491: Was typically attached to a multi-track recorder output. All channels provided stereo pan as well as four cue send buses that could be configured as pre- or post-fader and allowed individual monitoring via a pre-fade listen (PFL) function. Each channel could be routed directly to the left–right mix bus or to odd/even pairs of sub-mix buses. Current analog mixing console models: Current digital mixing consoles models: Microphone A microphone , colloquially called

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