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77-519: The AV100 series were similar to the Jukebox Multimedia with some updates including recording capability and faster performance. Also came in a 40 GB model. The device plays the standard formats (AVI, MP3, WMA, AVI, JPG, PNG, and BMP) and also comes in three sizes (20, 40, and 80 GB). The unit also features a line in source for audio and video, enabling users to record video from external sources, as well as recording audio from

154-435: 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

231-713: 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

308-403: 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,

385-592: 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

462-465: A begin/end recording control button. The AV500 was released on Friday June 10, 2005. It weighs 255 g for the 30 GB Model and 315 g for the 100 GB Model. Archos has replaced the AV product line with its Generation 4 series . The Archos AV700 was the turning point for Archos to change the way they sell these devices to the public. The previous slogan , "Think Smaller" was seen as inappropriate for

539-457: 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

616-441: 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

693-415: A digital camera and camcorder, with other selective addons available such as an FM radio remote control (which also enables radio recording) and a memory card reader. The 2004 edition Guinness World Records would state the 80 GB AV380 to be the multimedia jukebox with the largest capacity. Running the same software as AV300, the camera has been removed and a CompactFlash card slot has been built into

770-435: 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

847-492: 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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924-546: 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

1001-453: 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

1078-457: 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

1155-414: 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,

1232-598: 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

1309-432: 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

1386-587: 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

1463-424: 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

1540-476: 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

1617-643: 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

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1694-413: 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

1771-421: 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

1848-403: 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

1925-555: 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,

2002-399: 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

2079-607: Is similar to the GMini 500, but it has extra facilities (video recording and the new AV Pod ). The Archos AV500 series plays Divx / Xvid and WMV9 format video; MP3 and WAV audio files; and displays JPEG and BMP graphic files. It records video in the Divx format, either through its DVR function or through its minicam accessory, and it records sound either through its built-in microphone or through its analog input. It can play and record audio and video to or from external sources via

2156-441: 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

2233-477: 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

2310-405: 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

2387-406: 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

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2464-567: The AV5100 to designate the AV500 with a 100 GB hard drive. The AV5100 has an optional triple-life battery pack. Data transfer for the AV500 is provided through its USB ports. The AV500 can act as either a USB controller or a USB device, using its USB A and USB B ports respectively. A memory card reader would be read through the USB A port, for example, but a home computer would access the AV500 through

2541-463: 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

2618-515: 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

2695-845: The TV-Edition from the AV700, the AV700TV. The AV700 and AV500, along with the Gmini 402 , were sold under the PocketDish brand of Dish Network , though the original Archos logos remained. They were named the AV700E, AV500E, and AV402E respectively. While the AV700E and AV402E are listed as sold out, the AV500E is still listed as available even though the standard AV500 has been discontinued. Microphone A microphone , colloquially called

2772-608: 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 ;

2849-457: The USB B port. An optional camera attachment (digital minicam) was available for the AV500 from late December 2005 to mid-2006, when Archos discontinued its production. The minicam records video directly to the Archos' hard disk drive in Divx format. The camera is powered from the AV500 unit via its single video cable. A control unit in the middle of the cable contains a high-quality microphone and

2926-414: 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

3003-619: 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

3080-472: 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

3157-407: 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

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3234-408: The combined line / S/PDIF / ExtMic input or through its built in microphone . The player was criticized for its low battery performance and lack of DRM playback facilities. The battery playback on the device is stated at 3 and a half hours when watching video or 10 hours when listening to music. This device was released in 2003, and weighs 350 g. The optional AVCam 300 turns the device into

3311-425: 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

3388-533: The device. An included remote control enables one to control the entire device. The device plays all the standard formats as the AV300 with the addition of DRM-protected WMA files and standard WMV files. The device also supports Windows Media 's PlaysForSure platform. A limitation of the device at its release was that it wasn't specifically designed to play back ASP (Advanced Simple Profile) MP4 files, creating compatibility problems with several files encoded with

3465-490: 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

3542-486: 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

3619-466: 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

3696-413: 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

3773-770: 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

3850-513: 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

3927-423: 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

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4004-489: 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

4081-467: The mini- RCA jacks of its AV Pod. The AV500 case is made of brushed aluminum and forms a solid, rugged, dense box with a built-in LCD screen. Three formats of the AV500 were manufactured, containing either 40, 60, or 100 GB hard disk drives, each format using a different size and shape of battery. Sometimes the specific format is referenced by combining the model name with the hard disk drive format, e.g.,

4158-511: 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

4235-495: 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

4312-508: The popular XviD and DivX compression techniques. This device was released Wednesday June 30, 2004, and weighs 290 g (20 GB model) or 320 g (higher capacity models) Variants - AV530, AV560, AV580, AV5100 Just before the PMA 400 was released, there was a name conflict within the models. The PMA400 was scheduled to be released as the AV500. Ultimately, the name went to a new model of Digital Video Recorder (DVR). The Archos AV500

4389-471: 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

4466-415: 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

4543-637: The product directly. Image preview slides and DRM WMA support, as well as WMV access are also included. The unit is sold in many hard drive sizes, 20, 40, 60, and 80 GB and the AV4100 which is 100 GB in size. The actual size of the unit depends on the capacity, the AV420 (20 GB) was smaller than all of the other models and also has a smaller screen size. The cradle enables users to connect their device to their television, DVD players and stereos with ease without having loose wires or problems locating

4620-474: 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

4697-524: The purpose, so they then changed it to "On The Go". The AV700 comes in 40, 80 or 100 gigabyte models. The built-in screen resolution is 420 by 234. It is a digital video recorder and it is possible to record video from an external source, too. Like the Gmini 400 series, the AV700 also has a built-in Mophun gaming engine. This device was released Monday May 23, 2005, and weighs 590 g. In 2006, Archos developed

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4774-451: 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

4851-461: 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

4928-509: The right sockets. Archos built a copy protection system into the video recording software to make sure that while protected videos can be recorded on the device, they can't be transferred onto computers or the Internet. One feature of the AV300 was its lack of security and ability to rip movies but this was disabled for the AV400. If one records a protected DVD, then one can only play it back on

5005-498: 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

5082-436: 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

5159-538: 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

5236-403: 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,

5313-438: 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

5390-479: 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

5467-423: 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

5544-563: 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

5621-403: 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

5698-462: 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

5775-652: 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

5852-428: 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

5929-399: 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

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