90-491: [REDACTED] Look up mastering in Wiktionary, the free dictionary. Mastering may refer to Mastering (audio) , the process of preparing and transferring recorded audio from a source containing the final mix to a data storage device, the master Stem mastering , contains the same process as ordinary mastering but the individual audio tracks are grouped together into
180-493: A CD . Vinyl LP and cassettes have their own pre-duplication requirements for a finished master. Subsequently, it is rendered either to a physical medium, such as a CD-R or DVD-R, or to computer files, such as a Disc Description Protocol (DDP) file set or an ISO image . Regardless of what delivery method is chosen, the replicator factory will transfer the audio to a glass master that will generate metal stampers for replication. The process of audio mastering varies depending on
270-435: 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
360-403: 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,
450-592: 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
540-457: 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
630-441: 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
720-430: A few engineers who specialize in analog mastering. Mastering requires critical listening; however, software tools exist to facilitate the process. Results depend upon the intent of the engineer, their skills, the accuracy of the speaker monitors, and the listening environment. Mastering engineers often apply equalization and dynamic range compression in order to optimize sound translation on all playback systems. It
810-462: A few separated stems like drums, instruments, voices, etc. Bus mastering , a feature supported by many data bus architectures that enables a device connected to the bus to initiate transactions See also [ edit ] Master (disambiguation) Topics referred to by the same term [REDACTED] This disambiguation page lists articles associated with the title Mastering . If an internal link led you here, you may wish to change
900-418: A final master. Mastering engineers recommend leaving enough headroom on the mix to avoid distortion. The reduction of dynamics by the mix or mastering engineer has resulted in a loudness war in commercial recordings. The source material, ideally at the original resolution , is processed using equalization , compression , limiting and other processes. Additional operations, such as editing , specifying
990-435: 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
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#17327809619401080-492: 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
1170-546: 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
1260-453: 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
1350-427: A mastering context, though without the same degree of signal degradation as those introduced from processors within the analog domain. The quality of the results varies according to the algorithms used within these processors, which in some cases, can introduce distortions entirely exclusive to the digital domain. Real-time analyzers , phase oscilloscopes , and also peak, RMS, VU and K meters are frequently used within
1440-457: 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
1530-501: A record. After the introduction of the microphone and electronic amplifier in the mid-1920s, the mastering process became electro-mechanical, and electrically driven mastering lathes came into use for cutting master discs (the cylinder format by then having been superseded). Until the introduction of tape recording, master recordings were almost always cut direct-to-disc . Only a small minority of recordings were mastered using previously recorded material sourced from other discs. In
1620-474: A single-track mono or two-track stereo tape. Prior to the cutting of the master disc, the master tape was often subjected to further electronic treatment by a specialist mastering engineer. After the advent of tape it was found that, especially for pop recordings, master recordings could be made so that the resulting record would sound better. This was done by making fine adjustments to the amplitude of sound at different frequency bands ( equalization ) prior to
1710-414: 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,
1800-598: 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
1890-432: 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
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#17327809619401980-587: 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
2070-424: 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
2160-476: 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
2250-643: 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
2340-413: 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
2430-421: 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
2520-876: Is a person skilled in the practice of taking audio (typically musical content) that has been previously mixed in either the analogue or digital domain as mono, stereo, or multichannel formats and preparing it for use in distribution , whether by physical media such as a CD, vinyl record, or as some method of streaming audio. The mastering engineer is responsible for a final edit of a product and preparation for manufacturing copies. Although there are no official requirements to work as an audio mastering engineer, practitioners often have comprehensive domain knowledge of audio engineering, and in many cases, may hold an audio or acoustic engineering degree . Most audio engineers master music or speech audio material. The best mastering engineers might possess arrangement and production skills, allowing them to troubleshoot mix issues and improve
2610-403: 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
2700-555: 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,
2790-428: Is destined for vinyl release, additional processing, such as dynamic range reduction or frequency-dependent stereo–to–mono fold-down and equalization may be applied to compensate for the limitations of that medium. For compact disc release, start of track , end of track , and indexes are defined for playback navigation along with International Standard Recording Code (ISRC) and other information necessary to replicate
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2880-399: 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
2970-414: Is standard practice to make a copy of a master recording—known as a safety copy—in case the master is lost, damaged or stolen. In the earliest days of the recording industry, all phases of the recording and mastering process were entirely achieved by mechanical processes. Performers sang or played into a large acoustic horn and the master recording was created by the direct transfer of acoustic energy from
3060-421: Is the process of preparing and transferring recorded audio from a source containing the final mix to a data storage device (the master ), the source from which all copies will be produced (via methods such as pressing, duplication or replication ). In recent years, digital masters have become usual, although analog masters—such as audio tapes—are still being used by the manufacturing industry, particularly by
3150-968: Is to make a sonic impact. Prolonged periods of listening to improperly mastered recordings usually leads to hearing fatigue that ultimately takes the pleasure out of the listening experience. Microphone A microphone , colloquially called 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
3240-441: 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
3330-477: 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
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
3510-402: The diaphragm of the recording horn to the mastering lathe , typically located in an adjoining room. The cutting head, driven by the energy transferred from the horn, inscribed a modulated groove into the surface of a rotating cylinder or disc. These masters were usually made from either a soft metal alloy or from wax ; this gave rise to the colloquial term waxing , referring to the cutting of
3600-406: 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
3690-463: 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
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3780-515: 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
3870-608: 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 ;
3960-405: The actual recording process. Although tape and other technical advances dramatically improved the audio quality of commercial recordings in the post-war years, the basic constraints of the electro-mechanical mastering process remained, and the inherent physical limitations of the main commercial recording media—the 78 rpm disc and later the 7-inch 45 rpm single and 33-1/3 rpm LP record —meant that
4050-414: 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
4140-423: The audio analysis stage of the process as a means of rendering a visual representation of the audio, or signal, being analyzed. Most mastering engineer accolades are given for their ability to make a mix consistent with respect to subjective factors based on the perception of listeners, regardless of their playback systems and the environment. This is a difficult task due to the varieties of systems now available and
4230-414: The audio quality, dynamic range , and running time of master discs were still limited compared to later media such as the compact disc . From the 1950s until the advent of digital recording in the late 1970s, the mastering process typically went through several stages. Once the studio recording on multi-track tape was complete, a final mix was prepared and dubbed down to the master tape, usually either
4320-619: 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
4410-472: 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
4500-407: 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
4590-461: The cutting of the master disc. In large recording companies such as EMI , the mastering process was usually controlled by specialist staff technicians who were conservative in their work practices. These big companies were often reluctant to make changes to their recording and production processes. For example, EMI was very slow in taking up innovations in multi-track recording and did not install 8-track recorders in their Abbey Road Studios until
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#17327809619404680-425: 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
4770-490: 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
4860-416: The effect it has on the apparent qualitative attributes of the recording . For instance, a recording that sounds great on one speaker / amplifier combination playing CD audio, may sound drastically different on a computer-based system playing back a low- bitrate MP3 . Some engineers maintain that the main mastering engineer's task is to improve upon playback systems translations while the position of others
4950-486: 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
5040-466: 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
5130-408: The field of audio mastering, the debate is usually over the use of digital versus analog signal processing rather than the use of digital technology for storage of audio. Digital systems have higher performance and allow mixing to be performed at lower maximum levels. When mixing to 24-bits with peaks between −3 and −10 dBFS on a mix, the mastering engineer has enough headroom to process and produce
5220-420: The field of mastering are almost entirely dedicated to the purpose; engineered to a high standard, often possessing low signal-to-noise ratios [at nominal operating levels] and in many cases, the incorporation of parameter-recall, such as indented potentiometers, or in some more-sophisticated designs, via a digital-controller. Some advocates for digital software claim that plug-ins are capable of processing audio in
5310-410: The final sound. Generally, good mastering skills are based on experience, resulting from many years of practice. Generally, mastering engineers use a combination of specialized audio-signal processors, low-distortion-high-bandwidth loudspeakers (and corresponding amplifiers with which to drive them), within a dedicated, acoustically-optimized playback environment. The equipment and processors used within
5400-400: The gaps between tracks, adjusting level, fading in and out, noise reduction and other signal restoration and enhancement processes can also be applied as part of the mastering stage. The source material is put in the proper order, commonly referred to as assembly (or 'track') sequencing. These operations prepare the music for either digital or analog, e.g. vinyl, replication. If the material
5490-413: 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
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#17327809619405580-770: 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
5670-513: 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
5760-514: The late 1940s, the recording industry was revolutionized by the introduction of magnetic tape . Magnetic tape was invented for recording sound by Fritz Pfleumer in 1928 in Germany, based on the invention of magnetic wire recording by Valdemar Poulsen in 1898. Not until the end of World War II could the technology be found outside Europe. The introduction of magnetic tape recording enabled master discs to be cut separately in time and space from
5850-404: The late 1960s, more than a decade after the first commercial 8-track recorders were installed by American independent studios. In the 1990s, electro-mechanical processes were largely superseded by digital technology, with digital recordings stored on hard disk drives or digital tape and mastered to CD . The digital audio workstation (DAW) became common in many mastering facilities, allowing
5940-416: The link to point directly to the intended article. Retrieved from " https://en.wikipedia.org/w/index.php?title=Mastering&oldid=1153848867 " Category : Disambiguation pages Hidden categories: Short description is different from Wikidata All article disambiguation pages All disambiguation pages Mastering (audio) Mastering , a form of audio post production ,
6030-423: 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
6120-489: 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
6210-511: 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
6300-402: The off-line manipulation of recorded audio via a graphical user interface (GUI). Although many digital processing tools are common during mastering, it is also very common to use analog media and processing equipment for the mastering stage. Just as in other areas of audio, the benefits and drawbacks of digital technology compared to analog technology are still a matter for debate. However, in
6390-495: 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
6480-471: 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
6570-415: 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
6660-474: 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
6750-451: 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
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
6930-498: 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
7020-436: 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
7110-538: 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
7200-403: 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,
7290-438: 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
7380-417: The specific needs of the audio to be processed. Mastering engineers need to examine the types of input media, the expectations of the source producer or recipient, the limitations of the end medium and process the subject accordingly. General rules of thumb can rarely be applied. Steps of the process typically include the following: Examples of possible actions taken during mastering: A mastering engineer
7470-479: 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
7560-423: 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
7650-563: 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
7740-403: 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
7830-462: 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
7920-652: 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
8010-428: 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
8100-399: 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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