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RIAA Equalization
RIAA equalization is a specification for the recording and playback of phonograph records, established by the Recording Industry Association of America (RIAA). The purposes of the equalization are to permit greater recording times (by decreasing the mean width of each groove), to improve sound quality, and to reduce the groove damage that would otherwise arise during playback. The RIAA equalization curve was intended to operate as a ''de facto'' global industry standard for records since 1954, but when the change actually took place is difficult to determine. Before then, especially from 1940, each record company applied its own equalization; over 100 combinations of turnover and rolloff frequencies were in use, the main ones being Columbia-78, Decca-U.S., European (various), Victor-78 (various), Associated, BBC, NAB, Orthacoustic, World, Columbia LP, FFRR-78 and microgroove, and AES. The obvious consequence was that different reproduction results were obtained if the recordi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Columbia Records
Columbia Records is an American record label owned by Sony Music, Sony Music Entertainment, a subsidiary of Sony Corporation of America, the North American division of Japanese Conglomerate (company), conglomerate Sony. It was founded on January 15, 1889, evolving from the Graphophone#Commercialization, American Graphophone Company, the successor to the Volta Laboratory and Bureau#Commercialization of phonograph patents, Volta Graphophone Company. Columbia is the oldest surviving brand name in the recorded sound business, and the second major company to produce records. From 1961 to 1991, its recordings were released outside North America under the name CBS Records International, CBS Records to avoid confusion with EMI's Columbia Graphophone Company. Columbia is one of Sony Music's four flagship record labels, alongside former longtime rival RCA Records, as well as Arista Records and Epic Records. Artists who have recorded for Columbia include AC/DC, Adele, Aerosmith, Julie And ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Condenser Microphone
A microphone, colloquially called a mic or mike (), is a transducer that converts sound into an electrical signal. Microphones are used in many applications such as telephones, hearing aids, public address systems for concert halls and public events, motion picture production, live and recorded audio engineering, sound recording, two-way radios, megaphones, and radio and television broadcasting. They are also used in computers for recording voice, speech recognition, VoIP, and for other purposes such as ultrasonic sensors or knock sensors. Several types of microphone are used today, which employ different methods to convert 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 n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hertz
The hertz (symbol: Hz) is the unit of frequency in the International System of Units (SI), equivalent to one event (or cycle) per second. The hertz is an SI derived unit whose expression in terms of SI base units is s−1, meaning that one hertz is the reciprocal of one second. It is named after Heinrich Rudolf Hertz (1857–1894), the first person to provide conclusive proof of the existence of electromagnetic waves. Hertz are commonly expressed in multiples: kilohertz (kHz), megahertz (MHz), gigahertz (GHz), terahertz (THz). Some of the unit's most common uses are in the description of periodic waveforms and musical tones, particularly those used in radio- and audio-related applications. It is also used to describe the clock speeds at which computers and other electronics are driven. The units are sometimes also used as a representation of the energy of a photon, via the Planck relation ''E'' = ''hν'', where ''E'' is the photon's energy, ''ν'' is its freq ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Western Electric
The Western Electric Company was an American electrical engineering and manufacturing company officially founded in 1869. A wholly owned subsidiary of American Telephone & Telegraph for most of its lifespan, it served as the primary equipment manufacturer, supplier, and purchasing agent for the Bell System from 1881 to 1984 when it was dismantled. The company was responsible for many technological innovations as well as developments in industrial management. History In 1856, George Shawk, a craftsman and telegraph maker, purchased an electrical engineering business in Cleveland, Ohio. In January, 1869, Shawk had partnered with Enos M. Barton in the former Western Union repair shop of Cleveland, to manufacture burglar, fire alarms, and other electrical items. Both men were former Western Union employees. Shawk, was the Cleveland shop foreman and Barton, was a Rochester, New York telegrapher. During this Shawk and Barton partnership, one customer was an inventor sourcing parts an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bell Labs
Nokia Bell Labs, originally named Bell Telephone Laboratories (1925–1984), then AT&T Bell Laboratories (1984–1996) and Bell Labs Innovations (1996–2007), is an American industrial research and scientific development company owned by multinational company Nokia. With headquarters located in Murray Hill, New Jersey, the company operates several laboratories in the United States and around the world. Researchers working at Bell Laboratories are credited with the development of radio astronomy, the transistor, the laser, the photovoltaic cell, the charge-coupled device (CCD), information theory, the Unix operating system, and the programming languages B, C, C++, S, SNOBOL, AWK, AMPL, and others. Nine Nobel Prizes have been awarded for work completed at Bell Laboratories. Bell Labs had its origin in the complex corporate organization of the Bell System telephone conglomerate. In the late 19th century, the laboratory began as the Western Electric Engineering Department, l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sound Card
A sound card (also known as an audio card) is an internal expansion card that provides input and output of audio signals to and from a computer under the control of computer programs. The term ''sound card'' is also applied to external audio interfaces used for professional audio applications. Sound functionality can also be integrated onto the motherboard, using components similar to those found on plug-in cards. The integrated sound system is often still referred to as a ''sound card''. Sound processing hardware is also present on modern video cards with HDMI to output sound along with the video using that connector; previously they used a S/PDIF connection to the motherboard or sound card. Typical uses of sound cards or sound card functionality include providing the audio component for multimedia applications such as music composition, editing video or audio, presentation, education and entertainment (games) and video projection. Sound cards are also used for computer-base ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Line-level
Line level is the specified strength of an audio signal used to transmit analog audio between components such as CD and DVD players, television sets, audio amplifiers, and mixing consoles. Line level sits between other levels of audio signals. There are weaker signals such as those from microphones (microphone level or mic level) and instrument pickups (instrument level), and stronger signals, such as those used to drive headphones and loudspeakers (speaker level). The "strength" of these various signals does not necessarily refer to the output voltage of the source device; it also depends on its output impedance and output power capability. Consumer electronic devices concerned with audio (for example sound cards) often have a connector labeled ''line in'' and/or ''line out''. ''Line out'' provides an audio signal output and ''line in'' receives a signal input. The line in/out connections on consumer-oriented audio equipment are typically unbalanced, with a (0.14 inch, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Decibel
The decibel (symbol: dB) is a relative unit of measurement equal to one tenth of a bel (B). It expresses the ratio of two values of a power or root-power quantity on a logarithmic scale. Two signals whose levels differ by one decibel have a power ratio of 101/10 (approximately ) or root-power ratio of 10 (approximately ). The unit expresses a relative change or an absolute value. In the latter case, the numeric value expresses the ratio of a value to a fixed reference value; when used in this way, the unit symbol is often suffixed with letter codes that indicate the reference value. For example, for the reference value of 1 volt, a common suffix is " V" (e.g., "20 dBV"). Two principal types of scaling of the decibel are in common use. When expressing a power ratio, it is defined as ten times the logarithm in base 10. That is, a change in ''power'' by a factor of 10 corresponds to a 10 dB change in level. When expressing root-power quantities, a change in ''ampl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Magnetic Cartridge
A magnetic cartridge, more commonly called a phonograph cartridge or phono cartridge or (colloquially) a pickup, is an electromechanical transducer that is used to play records on a turntable. The cartridge contains a removable or permanently mounted stylus, the tip - usually a gemstone, such as diamond or sapphire - of which makes physical contact with the record's groove. In popular usage and in disc jockey jargon, the stylus, and sometimes the entire cartridge, is often called the needle. As the stylus tracks the serrated groove, it vibrates a cantilever on which is mounted a permanent magnet which moves between the magnetic fields of sets of electromagnetic coils in the cartridge (or vice versa: the coils are mounted on the cantilever, and the magnets are in the cartridge). The shifting magnetic fields generate an electrical current in the coils. The electrical signal generated by the cartridge can be amplified and then converted into sound by a loudspeaker. History Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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