Sound recording and reproduction is the electrical or mechanical inscription and re-creation of sound waves, usually used for the voice or for music.
The two main classes of sound recording technology are analog recording and digital recording.
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[edit] The cylinder phonograph
The first practical sound recording and reproduction device was the mechanical cylinder phonograph, invented by Thomas Edison in 1877 and patented in 1878, and in some ways resembled the phonoautograph patented by Edouard-Leon Scott de Martinville in 1857. The invention soon spread across the globe and over the next two decades the commercial recording, distribution and sale of sound recordings became a growing new international industry, with the most popular titles selling millions of units by the early 1900s. The development of mass-production techniques enabled cylinder recordings to become a major new consumer item in industrial countries and the cylinder was the main consumer format from the late 1880s until around 1910.
[edit] The disc
The next major technical development was the invention of the gramophone disc, generally credited to Emile Berliner and commercially introduced in the United States in 1889.
Discs were easier to manufacture, transport and store, and they had the additional benefit of being recordable/playable on both sides -- cylinders, by necessity, were single-sided. Sales of the Gramophone record overtook the cylinder ca. 1910, and by the end of World War I the disc had become the dominant commercial recording format. In various permutations, the audio disc format became the primary medium for consumer sound recordings until the end of the 20th century, and the double-sided 78rpm shellac disc was the standard consumer music format from the early 1930s to the late 1950s.
Although there was no universally accepted speed, and various companies offered discs that played at several different speeds, the major recording companies eventually settled on a de facto industry standard of 78 revolutions per minute, which gave the disc format its common nickname, the "seventy-eight".
[edit] Electrical recording
Sound recording began as a mechanical process and remained so until the 1920s, when a string of groundbreaking inventions in the field of electronics revolutionised sound recording and the young recording industry. These included sound transducers such as microphones and loudspeakers, recording devices such as the tape recorder and various electronic devices such as the mixing desk, designed for the amplification and modification of electrical sound signals.
After the Edison phonograph itself, arguably the most significant advances in sound recording were the electronic systems invented by two American scientists between 1900 and 1920.
In 1906 Lee De Forest invented the "Audion" triode vacuum-tube electronic valve, which could greatly amplify weak electrical signals, and this device became the basis of all subsequent electronic sound systems until the invention of the transistor. This was quickly followed by the invention of the Regenerative circuit, Super-Regenerative circuit and the Superheterodyne receiver circuit, all of which were invented and patented by the young electronics genius Edwin Armstrong between 1914 and 1922.
Armstrong's inventions made high-fidelity electrical sound recording and reproduction a practical reality, facilitating the development of the electronic amplifier and many other devices; by the early 1930s these systems had become standard in the recording and radio industry. Armstrong's groundbreaking inventions also made possible the broadcasting of long-range, high-quality radio transmissions of voice and music. The importance of Armstong's Superheterodyne circuit cannot be under-estimated -- it was the central component of almost all analog amplification and radio-frequency transmitter and receiver devices of the 20th century.
[edit] Other recording formats
This period also saw several other historic developments including the introduction of the first practical magnetic sound recording system, the magnetic wire recorder, which was based on the work of Danish inventor Valdemar Poulsen. Magnetic wire recorders were effective, but the sound quality was poor, so between the wars they were primarily used for voice recording and marketed as business dictating machines.
In the 1930s radio pioneer Guglielmo Marconi developed a system of magnetic sound recording using steel tape. This was the same material used to make razor blades, and not surprisingly the fearsome Marconi-Stille recorders were considered so dangerous that technicians had to operate them from another room for safety. Because of the high recording speeds required, they used enormous reels about one metre in diameter, and the thin tape frequently broke, sending jagged lengths of razor steel flying around the studio.
The other major invention in sound recording in this period was the optical sound-on-film system, also generally credited to Lee De Forest. Although famous early "Talkies" like The Jazz Singer used a sound-on-disc system, the film industry eventually adopted the optical sound-on-film system and it revolutionised the movie industry in the 1930s, ushering in the era of 'talking pictures'. Optical sound-on-film, based on the photoelectric cell, became the standard film audio system throughout the world until it was superseded in the 1960s.
[edit] Postwar advances
There were further advances during and just after World War II. British technicians developed full frequency range recording (FFRR) which for the first time enabled the creation of disc recordings that could reproduce sounds across the full spectrum of the human hearing range.
Shortly after the war the music industry was revolutionized by the two new innovations. The vinyl microgroove disc, greatly extended the duration, sound quality and durability of commercial records and led to the introduction of two new record formats. Columbia Records introduced the 33-1/3rpm long-playing (LP) record in 1947, soon followed by the RCA 45rpm 7-inch single, launched in 1948.
[edit] Magnetic tape
The other major inventions of this period were magnetic tape and the tape recorder. Paper-based tape was first used but was soon superseded by polyester and acetate backing due to dust drop and hiss. Acetate was more brittle than polyester and snapped easily. This technology, the basis for almost all commercial recording from the 1950s to the 1980s, was invented by German audio engineers in the 1930s, who also discovered the technique of AC biasing, which dramatically improved the frequency response of tape recordings. Tape recording was perfected just after the war by American audio engineer John T. Mullin, whose pioneering recorders were based on captured German recorders, and the Ampex company produced the first commercially available tape recorders in the late 1940s.
Magnetic tape brought about sweeping changes in both radio and the recording industry. Sound could be recorded, erased and re-recorded on the same tape many times, sounds could be duplicated from tape to tape with only minor loss of quality, and recordings could now be very precisely edited by physically cutting the tape and rejoining it.
Within a few years of the introduction of the first commercial tape recorder, the Ampex 200 model, launched in 1948, American musician-inventor Les Paul had invented the first multitrack tape recorder, bringing about another technical revolution in the recording industry. Tape made possible the first sound recordings totally created by electronic means, opening the way for the bold sonic experiments of the Musique Concrète school and avant garde composers like Karlheinz Stockhausen, which in turn led to the innovative pop music recordings of artists such as Frank Zappa, The Beatles and The Beach Boys.
Tape enabled the radio industry for the first time to pre-record many sections of program content such as advertising, which formerly had to be presented live, and it also enabled the creation and duplication of complex, high-fidelity, long-duration recordings of entire programs. It also, for the first time, allowed broadcasters, regulators and other interested parties to undertake comprehensive logging of radio broadcasts. Innovations like multitracking and tape echo enabled radio programs and advertisements to be pre-produced to a level of complexity and sophistication that was previously unattainable and tape also led to significant changes to the pacing of program content, thanks to the introduction of the endless-loop tape cartridge.
The vinyl microgroove record was introduced in the late 1940s, and the two main vinyl formats -- the 7-inch single and the 12-inch LP (long-playing) record -- had totally replaced the 78rpm shellac disc by the end of the 1950s.
[edit] Stereo and Hi-fi
Magnetic tape also enabled the development of the first practical commercial sound systems that could record and reproduce high-fidelity stereophonic sound. Experiments with stereo dated back to the 1880s and during the 1930s and 1940s there were many attempts to record in stereo using discs, but these were hampered by problems with synchronization.
The first major breakthrough in practical stereo sound was made by Bell Laboratories, who in 1937 demonstrated a practical system of two-channel stereo, using dual optical sound tracks on film. Major movie studios quickly developed three-track and four-track sound systems, and the first stereo sound recording in a commercial film was made by Judy Garland for the MGM movie Listen, Darling in 1938. The first commercially-released movie with a full stereo soundtrack was Walt Disney's Fantasia, released in 1940.
German audio engineers working on magnetic tape are reported to have developed stereo recording by 1943, but it was not until the introduction of the first commercial two-track tape recorders by Ampex in the late 1940s that stereo tape recording became commercially feasible. However, despite the availability of multitrack tape, stereo did not become the standard system for commercial music recording for some years and it remained a specialist market during the 1950s and 1960s.
Most pop singles were mixed into monophonic sound until the late 1960s and although famous albums such as The Beatles Sgt. Pepper's Lonely Hearts Club Band were issued in stereo, it was common for major pop releases to be issued in both mono and stereo until the early 1970s. Many Sixties pop albums now available only in stereo were originally intended to be released only in mono, and the so-called "stereo" version of these albums were created by simply separating the two tracks of the master tape. In the late Sixties, as stereo became more popular, many mono recordings (such as The Beach Boys' Pet Sounds) were remastered using the so-called "fake stereo" method, which spread the sound across the stereo field by directing higher-frequency sound into one channel and lower-frequency sounds into the other.
[edit] The Fifties and beyond
Magnetic tape transformed the recording industry, and by the late-1950s the vast majority of commercial recordings were being mastered on tape. The electronics revolution that followed the invention of the transistor brought other radical changes, the most important of which was the introduction of the world first "personal music device", the miniaturized transistor radio, which became a major consumer luxury item in the 1960s, transforming radio broadcasting from a static group experience into a mobile, personal listening activity.
The next important innovation was the compact cassette, introduced by the Philips electronics company in 1964. The cassette became a major consumer audio format and advances in microelectronics eventually led to the development of the Sony Walkman, introduced in the 1970s, which gave a major boost to the mass distribution of music recordings. Cassettes became the first successful consumer recording/re-recording medium as opposed to the gramophone record, which was a pre-recorded playback medium.
A key advance in audio fidelity came with the Dolby A noise reduction system, invented by Ray Dolby and introduced in 1966. Dolby's noise reduction system, which greatly improved the sound of cassette tape recordings, also found wide application in the recording and film industries. Dolby A was crucial to the popularisation and commercial success of the compact cassette as a domestic recording and playback medium, and became a part of the booming "hi-fi" market of the 1970s and beyond.
The multitrack audio cartridge was in wide use in the radio industry, from the late 1950s to the 1980s, but in the 1960s the pre-recorded 8-track cartridge was launched as a consumer audio format. Aimed particularly at the automotive market, they were the first practical, affordable car hi-fi systems, and they offered superior sound quality to the compact cassette. However the smaller size and greater durability -- augmented by the ability to create home-recorded music "compilations" -- saw the cassette become the dominant consumer format for portable audio devices in the 1970s and 1980s.
There had been experiments with multi-channel sound for many years -- usually for special musical or cultural events -- but the first commercial application of the concept came in the early 1970s with the introduction of Quadraphonic sound. This spin-off development from multitrack recording used four tracks (instead of the two used in stereo) and four speakers to create a 360-degree audio field around the listener. Following the release of the first consumer 4-channel hi-fi systems, a number of popular albums were released in the Quadraphonic format; among the best known are Mike Oldfield's Tubular Bells and Pink Floyd's The Dark Side of the Moon. Quadraphonic sound was not a commercial success, and it eventually faded out in the late 1970s, although this early venture paved the way for the eventual introduction of domestic Surround Sound systems, which have gained enormous popularity since the introduction of the DVD.
The replacement of the valve by the smaller, cooler and less power-hungry transistor also accelerated the sale of consumer high-fidelity "hi-fi" sound systems from the 1960s onward. In the 1950s and 1960s most record players were monophonic and relatively low fidelity in sound quality, and few consumers could afford high-quality stereophonic sound systems. In the 1960s American manufacturers introduced a new generation of "modular" hi-fi components -- turntables, integrated amplifiers, tape recorders and other ancillary equipment (like the graphic equaliser), which could be connected together to create a complete home sound system. These developments were rapidly taken up by the Japanese electronics companies, who flooded the world market with relatively cheap, high-quality components. By the 1980s, corporations like Sony had become world leaders in the music recording and playback industry.
[edit] Digital recording
The invention of digital sound recording and the compact disc in 1983 brought massive improvements in the durability and sound quality of consumer recordings. The CD initiated another massive wave of change in the consumer music industry, with vinyl records effectively relegated to a small niche market by the mid-1990s.
The most recent and revolutionary developments have been in digital recording, with the invention of purely electronic consumer recording formats such as the WAV digital music file and the compressed file type, the MP3. This generated a new type of portable solid-state computerised digital audio player, the MP3 player. The most popular variety is the Apple iPod. Another invention, by Sony, was the minidisc player, using ATRAC compression on small, cheap, re-writeable discs. This was in vogue in the 1990s, and is still popular, especially in a newer, longer playing and higher fidelity version. New technologies such as Super Audio CD and DVD-A continue to set very hi-fi digital standards.
This technology spreads across various associated fields, from Hi-Fi to Professional audio, Internet radio and Podcasting.
Technological developments in recording and editing have transformed the record, movie and television industries in recent decades. Audio editing became practicable with the invention of magnetic tape recording, but the use of computers has made editing operations faster and easier to execute, and the use of hard-drives for storage has made recording cheaper. We now divide the process of making a recording into tracking, mixing and mastering. Multitrack recording makes it possible to capture sound from several microphones, or from different 'takes' to tape or disc with maximum headroom and quality, allowing maximum flexibility in the mixing and mastering stages for editing, level balancing, compressing and limiting, and the addition of effects such as reverberation, equalisation, flanging and many more.
The first multitrack recording made using magnetic tape was "How High the Moon" by Les Paul, on which Paul played eight overdubbed guitar tracks. In the 1960s Brian Wilson of The Beach Boys, Frank Zappa and The Beatles (with producer George Martin) were among the first popular artists to explore the possibilities of multitrack techniques and effects on their landmark albums Pet Sounds, Freak Out! and Sgt. Pepper's Lonely Hearts Club Band.
In the 1920s, the first talkies came out, featuring the new sound-on-film technology which used photoelectric cells to record and reproduce sound signals that were optically recorded directly onto the movie film. The advent of talkies, spearheaded by The Jazz Singer in 1927, saw the rapid demise of live cinema musicians and orchestras, which were replaced with pre-recorded soundtracks, causing the loss of many jobs.[1] The American Federation of Musicians took out ads in newspapers, protesting the replacement of real musicians with mechanical playing devices, especially in theatres. [2]