Sound recording and reproduction
Encyclopedia
Sound recording and reproduction is an electrical or mechanical inscription and re-creation of sound
Sound
Sound is a mechanical wave that is an oscillation of pressure transmitted through a solid, liquid, or gas, composed of frequencies within the range of hearing and of a level sufficiently strong to be heard, or the sensation stimulated in organs of hearing by such vibrations.-Propagation of...

 waves, such as spoken voice, singing, instrumental music, or sound effects. The two main classes of sound recording technology are analog recording
Analog recording
Analog recording is a technique used for the recording of analog signals which among many possibilities include audio frequency, analog audio and analog video information for later playback.Analog recording methods store signals as a continual wave in or on the media...

 and digital recording
Digital recording
In digital recording, digital audio and digital video is directly recorded to a storage device as a stream of discrete numbers, representing the changes in air pressure for audio and chroma and luminance values for video through time, thus making an abstract template for the original sound or...

. Acoustic analog recording is achieved by a small microphone
Microphone
A microphone is an acoustic-to-electric transducer or sensor that converts sound into an electrical signal. In 1877, Emile Berliner invented the first microphone used as a telephone voice transmitter...

 diaphragm that can detect changes in atmospheric pressure (acoustic
Acoustics
Acoustics is the interdisciplinary science that deals with the study of all mechanical waves in gases, liquids, and solids including vibration, sound, ultrasound and infrasound. A scientist who works in the field of acoustics is an acoustician while someone working in the field of acoustics...

 sound waves) and record them as a graphic representation of the sound waves on a medium such as a phonograph
Phonograph
The phonograph record player, or gramophone is a device introduced in 1877 that has had continued common use for reproducing sound recordings, although when first developed, the phonograph was used to both record and reproduce sounds...

 (in which a stylus senses grooves on a record). In magnetic tape
Magnetic tape
Magnetic tape is a medium for magnetic recording, made of a thin magnetizable coating on a long, narrow strip of plastic. It was developed in Germany, based on magnetic wire recording. Devices that record and play back audio and video using magnetic tape are tape recorders and video tape recorders...

 recording, the sound waves vibrate the microphone diaphragm and are converted into a varying electric current
Electric current
Electric current is a flow of electric charge through a medium.This charge is typically carried by moving electrons in a conductor such as wire...

, which is then converted to a varying magnetic field
Magnetic field
A magnetic field is a mathematical description of the magnetic influence of electric currents and magnetic materials. The magnetic field at any given point is specified by both a direction and a magnitude ; as such it is a vector field.Technically, a magnetic field is a pseudo vector;...

 by an electromagnet
Electromagnet
An electromagnet is a type of magnet in which the magnetic field is produced by the flow of electric current. The magnetic field disappears when the current is turned off...

, which makes a representation of the sound as magnetized areas on a plastic tape with a magnetic coating on it. Analog sound reproduction is the reverse process, with a bigger loudspeaker
Loudspeaker
A loudspeaker is an electroacoustic transducer that produces sound in response to an electrical audio signal input. Non-electrical loudspeakers were developed as accessories to telephone systems, but electronic amplification by vacuum tube made loudspeakers more generally useful...

 diaphragm causing changes to atmospheric pressure to form acoustic sound waves. Electronically generated sound waves may also be recorded directly from devices such as an electric guitar pickup or a synthesizer
Synthesizer
A synthesizer is an electronic instrument capable of producing sounds by generating electrical signals of different frequencies. These electrical signals are played through a loudspeaker or set of headphones...

, without the use of acoustics in the recording process other than the need for musicians to hear how well they are playing during recording sessions.

Digital recording and reproduction converts the analog sound signal picked up by the microphone to a digital form by a process of digitization, allowing it to be stored and transmitted
Data transmission
Data transmission, digital transmission, or digital communications is the physical transfer of data over a point-to-point or point-to-multipoint communication channel. Examples of such channels are copper wires, optical fibres, wireless communication channels, and storage media...

 by a wider variety of media. Digital recording stores audio as a series of binary
Binary numeral system
The binary numeral system, or base-2 number system, represents numeric values using two symbols, 0 and 1. More specifically, the usual base-2 system is a positional notation with a radix of 2...

 numbers representing samples of the amplitude
Amplitude
Amplitude is the magnitude of change in the oscillating variable with each oscillation within an oscillating system. For example, sound waves in air are oscillations in atmospheric pressure and their amplitudes are proportional to the change in pressure during one oscillation...

 of the audio signal
Audio signal
An audio signal is an analog representation of sound, typically as an electrical voltage. Audio signals may be synthesized directly, or may originate at a transducer such as a microphone, musical instrument pickup, phonograph cartridge, or tape head. Loudspeakers or headphones convert an electrical...

 at equal time intervals, at a sample rate high enough to convey all sounds capable of being heard
Hearing
Hearing may refer to:* Hearing , the sense by which sound is perceived* Hearing , a person who has hearing within normal parameters* Hearing , a legal proceeding before a court or other decision making body or officer...

. Digital recordings are considered higher quality than analog recordings not necessarily because they have higher fidelity
High fidelity
High fidelity—or hi-fi—reproduction is a term used by home stereo listeners and home audio enthusiasts to refer to high-quality reproduction of sound or images, to distinguish it from the poorer quality sound produced by inexpensive audio equipment...

 (wider frequency response
Frequency response
Frequency response is the quantitative measure of the output spectrum of a system or device in response to a stimulus, and is used to characterize the dynamics of the system. It is a measure of magnitude and phase of the output as a function of frequency, in comparison to the input...

 or dynamic range
Dynamic range
Dynamic range, abbreviated DR or DNR, is the ratio between the largest and smallest possible values of a changeable quantity, such as in sound and light. It is measured as a ratio, or as a base-10 or base-2 logarithmic value.-Dynamic range and human perception:The human senses of sight and...

), but because the digital format can prevent much loss of quality found in analog recording due to noise and electromagnetic interference
Electromagnetic interference
Electromagnetic interference is disturbance that affects an electrical circuit due to either electromagnetic induction or electromagnetic radiation emitted from an external source. The disturbance may interrupt, obstruct, or otherwise degrade or limit the effective performance of the circuit...

 in playback, and mechanical deterioration or damage to the storage medium. A digital audio
Digital audio
Digital audio is sound reproduction using pulse-code modulation and digital signals. Digital audio systems include analog-to-digital conversion , digital-to-analog conversion , digital storage, processing and transmission components...

 signal must be reconverted to analog form during playback before it is applied to a loudspeaker or earphones.

History

The first devices for recording and reproducing sound were mechanical in nature and could not record arbitrary sounds such as the human voice. The automatic reproduction of music can be traced back as far as the 9th century, when the Banū Mūsā
Banu Musa
The Banū Mūsā brothers , namely Abū Jaʿfar Muḥammad ibn Mūsā ibn Shākir , Abū al‐Qāsim Aḥmad ibn Mūsā ibn Shākir and Al-Ḥasan ibn Mūsā ibn Shākir , were three 9th-century Persian scholars of Baghdad who are known for their Book of Ingenious Devices on automata and mechanical devices...

 brothers invented "the earliest known mechanical musical instrument
Musical box
A music box is a 19th century automatic musical instrument that produces sounds by the use of a set of pins placed on a revolving cylinder or disc so as to pluck the tuned teeth of a steel comb. They were developed from musical snuff boxes of the 18th century and called carillons à musique...

", in this case a hydropower
Hydropower
Hydropower, hydraulic power, hydrokinetic power or water power is power that is derived from the force or energy of falling water, which may be harnessed for useful purposes. Since ancient times, hydropower has been used for irrigation and the operation of various mechanical devices, such as...

ed organ
Organ (music)
The organ , is a keyboard instrument of one or more divisions, each played with its own keyboard operated either with the hands or with the feet. The organ is a relatively old musical instrument in the Western musical tradition, dating from the time of Ctesibius of Alexandria who is credited with...

 which played interchangeable cylinders automatically. According to Charles B. Fowler, this "cylinder with raised pins on the surface remained the basic device to produce and reproduce music mechanically until the second half of the nineteenth century." The Banu Musa brothers also invented an automatic
Automaton
An automaton is a self-operating machine. The word is sometimes used to describe a robot, more specifically an autonomous robot. An alternative spelling, now obsolete, is automation.-Etymology:...

 flute
Flute
The flute is a musical instrument of the woodwind family. Unlike woodwind instruments with reeds, a flute is an aerophone or reedless wind instrument that produces its sound from the flow of air across an opening...

 player which appears to have been the first programmable machine
Program (machine)
A program is a list of instructions written in a programming language that is used to control the behavior of a machine, often a computer ....

. In 1206, Al-Jazari
Al-Jazari
Abū al-'Iz Ibn Ismā'īl ibn al-Razāz al-Jazarī was a Muslim polymath: a scholar, inventor, mechanical engineer, craftsman, artist, mathematician and astronomer from Al-Jazira, Mesopotamia, who lived during the Islamic Golden Age...

 invented a programmable musical automaton
Automaton
An automaton is a self-operating machine. The word is sometimes used to describe a robot, more specifically an autonomous robot. An alternative spelling, now obsolete, is automation.-Etymology:...

 featuring humanoid
Humanoid robot
A humanoid robot or an anthropomorphic robot is a robot with its overall appearance, based on that of the human body, allowing interaction with made-for-human tools or environments. In general humanoid robots have a torso with a head, two arms and two legs, although some forms of humanoid robots...

 musicians and drummers which could be made to play different rhythms and drum patterns if the pegs were moved around. According to Charles B. Fowler, the automata were a robot
Robot
A robot is a mechanical or virtual intelligent agent that can perform tasks automatically or with guidance, typically by remote control. In practice a robot is usually an electro-mechanical machine that is guided by computer and electronic programming. Robots can be autonomous, semi-autonomous or...

 band
Musical ensemble
A musical ensemble is a group of people who perform instrumental or vocal music. In classical music, trios or quartets either blend the sounds of musical instrument families or group together instruments from the same instrument family, such as string ensembles or wind ensembles...

 which performed "more than fifty facial and body actions during each musical selection."

In the 14th century, Flanders
Flanders
Flanders is the community of the Flemings but also one of the institutions in Belgium, and a geographical region located in parts of present-day Belgium, France and the Netherlands. "Flanders" can also refer to the northern part of Belgium that contains Brussels, Bruges, Ghent and Antwerp...

 introduced a mechanical bell-ringer controlled by a rotating cylinder. Similar designs appeared in barrel organ
Barrel organ
A barrel organ is a mechanical musical instrument consisting of bellows and one or more ranks of pipes housed in a case, usually of wood, and often highly decorated...

s (15th century), musical clock
Musical clock
A Musical clock is a clock that marks the hours of the day with a musical tune played from a spiked cylinder either on bells, organ pipes, bellows, combs and even dulcimer strings....

s (1598), barrel piano
Barrel piano
A barrel piano is a forerunner of the modern player piano. Unlike the pneumatic player piano, a barrel piano is usually powered by turning a hand crank, though coin operated models powered by clockwork were used to provide music in establishments such as pubs and cafés...

s (1805), and musical box
Musical box
A music box is a 19th century automatic musical instrument that produces sounds by the use of a set of pins placed on a revolving cylinder or disc so as to pluck the tuned teeth of a steel comb. They were developed from musical snuff boxes of the 18th century and called carillons à musique...

es (1815).

All of these machines could play stored music, but they could not play arbitrary sounds, could not record a live performance, and were limited by the physical size of the medium. In 1796, a Swiss watchmaker named Antoine Favre described his idea for what we now call the cylinder musical box
Musical box
A music box is a 19th century automatic musical instrument that produces sounds by the use of a set of pins placed on a revolving cylinder or disc so as to pluck the tuned teeth of a steel comb. They were developed from musical snuff boxes of the 18th century and called carillons à musique...

. This can be considered an early method of recording a melody, although it does not record an arbitrary sound and does not record automatically. "Playback" however is automatic. The fairground organ
Fairground organ
A fairground organ is a pipe organ designed for use in a commercial public fairground setting to provide loud music to accompany fairground rides and attractions...

, developed in 1892, used a similar system of accordion-folded punched cardboard books.

The player piano
Player piano
A player piano is a self-playing piano, containing a pneumatic or electro-mechanical mechanism that operates the piano action via pre-programmed music perforated paper, or in rare instances, metallic rolls. The rise of the player piano grew with the rise of the mass-produced piano for the home in...

, first demonstrated in 1876, used a punched paper scroll that could store an arbitrarily long piece of music. The most sophisticated of the piano rolls were "hand-played", meaning that the roll represented the actual performance of an individual, not just a transcription of the sheet music. This technology to record a live performance onto a piano roll was not developed until 1904. Piano rolls have been in continuous mass production since around 1898. A 1908 U.S. Supreme Court copyright case noted that, in 1902 alone, there were between 70,000 and 75,000 player pianos manufactured, and between 1,000,000 and 1,500,000 piano rolls produced. The use of piano rolls began to decline in the 1920s although one type is still being made today.
The first device that could record sound mechanically (but could not play it back) was the phonautograph
Phonautograph
The phonautograph is the earliest known device for recording sound. Previously, tracings had been obtained of the sound-producing vibratory motions of tuning forks and other objects by physical contact with them, but not of actual sound waves as they propagated through air or other media. Invented...

, developed in 1857 by Parisian inventor Édouard-Léon Scott de Martinville
Édouard-Léon Scott de Martinville
Édouard-Léon Scott de Martinville was a French printer and bookseller who lived in Paris. He invented the earliest known sound recording device, the phonautograph, which was patented in France on 25 March 1857....

. The earliest known recordings of the human voice were phonautograms also made in 1857. These earliest known recordings include a dramatic reading in French of Shakespeare's Othello and music played on a guitar and trumpet. The recordings consist of groups of wavy lines scratched by a stylus onto fragile paper that was blackened by the soot from an oil lamp. One of his phonautograms of Au Clair de la Lune, a French folk song, was digitally converted to sound in 2008.

Phonograph cylinder

The first practical sound recording and reproduction device was the mechanical phonograph cylinder
Phonograph cylinder
Phonograph cylinders were the earliest commercial medium for recording and reproducing sound. Commonly known simply as "records" in their era of greatest popularity , these cylinder shaped objects had an audio recording engraved on the outside surface which could be reproduced when the cylinder was...

, invented by Thomas Edison
Thomas Edison
Thomas Alva Edison was an American inventor and businessman. He developed many devices that greatly influenced life around the world, including the phonograph, the motion picture camera, and a long-lasting, practical electric light bulb. In addition, he created the world’s first industrial...

 in 1877 and patented in 1878. 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.

Disc phonograph

The next major technical development was the invention of the gramophone disc
Berliner Gramophone
Berliner Gramophone was an early record label, the first company to produce disc "gramophone records" .-History:...

, generally credited to Emile Berliner
Emile Berliner
Emile Berliner or Emil Berliner was a German-born American inventor. He is best known for developing the disc record gramophone...

 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 louder (marginally) than cylinders, which by necessity, were single-sided. Sales of the Gramophone record
Gramophone record
A gramophone record, commonly known as a phonograph record , vinyl record , or colloquially, a record, is an analog sound storage medium consisting of a flat disc with an inscribed, modulated spiral groove...

 overtook the cylinder ca. 1910, and by the end of World War I the disc had become the dominant commercial recording format. Edison, who was the main producer of cylinders, created the Edison Disc Record
Edison Disc Record
The Edison Disc, also known as a Diamond Disc record, was a type of audio disc record marketed by Edison Records from 1912 to 1929. They were known as Diamond disc because the reproducer fitted to the matching Edison disc player was fitted with a diamond stylus...

 in an attempt to regain his market. 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 78 rpm shellac disc was the standard consumer music format from the early 1910s 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 nominally 78 revolutions per minute, though the actual speed differed between America and the rest of the world. The specified speed was 78.26 rpm in America and 77.92 rpm throughout the rest of the world, the difference in speeds a result of the difference in cycle frequencies of the AC power driving the synchronous motor
Synchronous motor
A synchronous electric motor is an AC motor distinguished by a rotor spinning with coils passing magnets at the same rate as the power supply frequency and resulting rotating magnetic field which drives it....

 and available gearing ratios. The nominal speed of the disc format gave rise to its common nickname, the "seventy-eight" (though not until other speeds had become available). Discs were made of shellac or similar brittle plastic-like materials, played with needles made from a variety of materials including mild steel, thorn and even sapphire. Discs had a distinctly limited playing life which was heavily dependent on how they were reproduced.

The earlier, purely acoustic methods of recording had limited sensitivity and frequency range. Mid-frequency range notes could be recorded but very low and very high frequencies could not. Instruments such as the violin transferred poorly to disc; however this was partially solved by retrofitting a conical horn to the sound box of the violin. The horn was no longer required once electrical recording was developed.
The Vinyl microgroove was invented by a Hungarian engineer Peter Carl Goldmark
Peter Carl Goldmark
Peter Carl Goldmark was a German-Hungarian engineer who, during his time with Columbia Records, was instrumental in developing the long-playing microgroove 33-1/3 rpm vinyl phonograph disc, the standard for incorporating multiple or lengthy recorded works on a single disc for two generations...

.
The vinyl
Vinyl
A vinyl compound is any organic compound that contains a vinyl group ,which are derivatives of ethene, CH2=CH2, with one hydrogen atom replaced with some other group...

 microgroove record
Gramophone record
A gramophone record, commonly known as a phonograph record , vinyl record , or colloquially, a record, is an analog sound storage medium consisting of a flat disc with an inscribed, modulated spiral groove...

 was introduced in the late 1940s, and the two main vinyl formats — the 7-inch single
Single (music)
In music, a single or record single is a type of release, typically a recording of fewer tracks than an LP or a CD. This can be released for sale to the public in a variety of different formats. In most cases, the single is a song that is released separately from an album, but it can still appear...

 turning at 45 rpm and the 12-inch LP
LP album
The LP, or long-playing microgroove record, is a format for phonograph records, an analog sound storage medium. Introduced by Columbia Records in 1948, it was soon adopted as a new standard by the entire record industry...

 (long-playing) record turning at 33 rpm — had totally replaced the 78 rpm shellac
Shellac
Shellac is a resin secreted by the female lac bug, on trees in the forests of India and Thailand. It is processed and sold as dry flakes , which are dissolved in ethyl alcohol to make liquid shellac, which is used as a brush-on colorant, food glaze and wood finish...

 (sometimes vinyl) disc by the end of the 1950s. Vinyl offered improved performance, both in stamping and in playback, and came to be generally played with polished diamond styli, and when played properly (precise tracking weight, etc.) offered longer life. Vinyl records were, over-optimistically, advertised as "unbreakable". They were not, but were much less brittle and breakable than shellac. Nearly all were tinted black, but some were colored, as red, swirled, translucent, etc.

Electrical recording

Sound recording began as a mechanical process and remained so until the early 1920s (with the exception of the 1899 Telegraphone
Valdemar Poulsen
Valdemar Poulsen was a Danish engineer who developed a magnetic wire recorder in 1899.-Biography:He was born on 23 November 1869 in Copenhagen...

) when a string of groundbreaking inventions in the field of electronics
Electronics
Electronics is the branch of science, engineering and technology that deals with electrical circuits involving active electrical components such as vacuum tubes, transistors, diodes and integrated circuits, and associated passive interconnection technologies...

 revolutionised sound recording and the young recording industry. These included sound transducers such as microphones and loudspeakers, and various electronic devices such as the mixing desk, designed for the amplification
Amplifier
Generally, an amplifier or simply amp, is a device for increasing the power of a signal.In popular use, the term usually describes an electronic amplifier, in which the input "signal" is usually a voltage or a current. In audio applications, amplifiers drive the loudspeakers used in PA systems to...

 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 1924. In 1906 Lee De Forest
Lee De Forest
Lee De Forest was an American inventor with over 180 patents to his credit. De Forest invented the Audion, a vacuum tube that takes relatively weak electrical signals and amplifies them. De Forest is one of the fathers of the "electronic age", as the Audion helped to usher in the widespread use...

 invented the "Audion" triode
Triode
A triode is an electronic amplification device having three active electrodes. The term most commonly applies to a vacuum tube with three elements: the filament or cathode, the grid, and the plate or anode. The triode vacuum tube was the first electronic amplification device...

 vacuum-tube, electronic valve, which could greatly amplify weak electrical signals (one early use was to amplify long distance telephone in 1915), which became the basis of all subsequent electrical sound systems until the invention of the transistor
Transistor
A transistor is a semiconductor device used to amplify and switch electronic signals and power. It is composed of a semiconductor material with at least three terminals for connection to an external circuit. A voltage or current applied to one pair of the transistor's terminals changes the current...

. The valve was quickly followed by the invention of the Regenerative circuit
Regenerative circuit
The regenerative circuit or "autodyne" allows an electronic signal to be amplified many times by the same vacuum tube or other active component such as a field effect transistor. It consists of an amplifying vacuum tube or transistor with its output connected to its input through a feedback...

, Super-Regenerative circuit and the Superheterodyne receiver
Superheterodyne receiver
In electronics, a superheterodyne receiver uses frequency mixing or heterodyning to convert a received signal to a fixed intermediate frequency, which can be more conveniently processed than the original radio carrier frequency...

 circuit, all of which were invented and patented by the young electronics genius Edwin Armstrong
Edwin Armstrong
Edwin Howard Armstrong was an American electrical engineer and inventor. Armstrong was the inventor of modern frequency modulation radio....

 between 1914 and 1922. Armstrong's inventions made higher fidelity electrical sound recording and reproduction a practical reality, facilitating the development of the electronic amplifier
Amplifier
Generally, an amplifier or simply amp, is a device for increasing the power of a signal.In popular use, the term usually describes an electronic amplifier, in which the input "signal" is usually a voltage or a current. In audio applications, amplifiers drive the loudspeakers used in PA systems to...

 and many other devices; after 1925 these systems had become standard in the recording and radio industry.

While Armstrong published studies about the fundamental operation of the triode vacuum tube before World War I, inventors like Orlando R. Marsh
Orlando R. Marsh
Orlando R. Marsh was an electrical engineer raised in Wilmette, Illinois. In early 1920s Chicago, Illinois he pioneered electrical recording of phonograph discs with microphones when acoustic recording with horns was commonplace...

 and his Marsh Laboratories
Autograph Records
Autograph Records was a United States record label of the 1920s.Autograph was a small label, owned by Marsh Laboratories Incorporated of Chicago, Illinois. Marsh Laboratories in turn was owned by electrical engineer Orlando R. Marsh...

, as well as scientists at Bell Telephone Laboratories, achieved their own understanding about the triode and were utilizing the Audion as a repeater in weak telephone circuits. By 1925 it was possible to place a long distance telephone call with these repeaters between New York and San Francisco in 20 minutes, both parties being clearly heard. With this technical prowess, Joseph P. Maxfield and Henry C. Harrison from Bell Telephone Laboratories were skilled in using mechanical analogs of electrical circuits and applied these principles to sound recording and reproduction. They were ready to demonstrate their results by 1924 using the Wente condenser microphone and the vacuum tube amplifier to drive the "rubber line" wax recorder to cut a master audio disc.

Meanwhile, radio continued to develop. Armstrong's groundbreaking inventions (including FM radio) also made possible the broadcasting
Broadcasting
Broadcasting is the distribution of audio and video content to a dispersed audience via any audio visual medium. Receiving parties may include the general public or a relatively large subset of thereof...

 of long-range, high-quality radio transmissions of voice and music. The importance of Armstrong's Superheterodyne circuit cannot be over-estimated — it is the central component of almost all analog amplification and both analog and digital radio-frequency transmitter
Transmitter
In electronics and telecommunications a transmitter or radio transmitter is an electronic device which, with the aid of an antenna, produces radio waves. The transmitter itself generates a radio frequency alternating current, which is applied to the antenna. When excited by this alternating...

 and receiver
Receiver (radio)
A radio receiver converts signals from a radio antenna to a usable form. It uses electronic filters to separate a wanted radio frequency signal from all other signals, the electronic amplifier increases the level suitable for further processing, and finally recovers the desired information through...

 devices to this day.
Beginning during World War One, experiments were undertaken in the United States and Great Britain to reproduce among other things, the sound of a Submarine (u-boat) for training purposes. The acoustical recordings of that time proved entirely unable to reproduce the sounds, and other methods were actively sought. Radio had developed independently to this point, and now Bell Laboritories sought a marriage of the two disparate technologies, greater than the two separately. The first experiments were not very promising, but by 1920 greater sound fidelity was achieved using the electrical system than had ever been realized acoustically. One early recording made without fanfare or announcement was the dedication of the Tomb of the Unknown Soldier at Arlington Cemetery.

By early 1924 such dramatic progress had been made, that Bell Labs arranged a demonstration for the leading recording companies, the Victor Talking Machine Company
Victor Talking Machine Company
The Victor Talking Machine Company was an American corporation, the leading American producer of phonographs and phonograph records and one of the leading phonograph companies in the world at the time. It was headquartered in Camden, New Jersey....

, and the Columbia Phonograph Co.
Columbia Records
Columbia Records is an American record label, owned by Japan's Sony Music Entertainment, operating under the Columbia Music Group with Aware Records. It was founded in 1888, evolving from an earlier enterprise, the American Graphophone Company — successor to the Volta Graphophone Company...

 (Edison
Edison Records
Edison Records was one of the earliest record labels which pioneered recorded sound and was an important player in the early recording industry.- Early phonographs before commercial mass produced records :...

 was left out due to their decreasing market share and a stubborn Thomas Edison
Thomas Edison
Thomas Alva Edison was an American inventor and businessman. He developed many devices that greatly influenced life around the world, including the phonograph, the motion picture camera, and a long-lasting, practical electric light bulb. In addition, he created the world’s first industrial...

). Columbia, always in financial straits, could not afford it, and Victor, essentially leaderless since the mental collapse of founder Eldridge Johnson, left the demonstration without comment. English Columbia
Columbia Graphophone Company
The Columbia Graphophone Company was one of the earliest gramophone companies in the United Kingdom. Under EMI, as Columbia Records, it became a very successful label in the 1950s and 1960s...

, by then a separate company, got hold of a test pressing made by Pathé from these sessions, and realized the immediate and urgent need to have the new system. Bell was only offering its method to United States companies, and to circumvent this, Managing Director Louis Sterling of English Columbia, bought his once parent company, and signed up for electrical recording. Although they were contemplating a deal, Victor Talking Machine was apprised of the new Columbia deal, so they too quickly signed. Columbia made its first released electrical recordings on February 25, 1925, with Victor following a few weeks later. The two then agreed privately to "be quiet" until November 1925, by which time enough electrical repertory would be available.

Other recording formats

In the 1920s, the early talkies featured the new sound-on-film
Sound-on-film
Sound-on-film refers to a class of sound film processes where the sound accompanying picture is physically recorded onto photographic film, usually, but not always, the same strip of film carrying the picture. Sound-on-film processes can either record an analog sound track or digital sound track,...

 technology which used photoelectric cells
Solar cell
A solar cell is a solid state electrical device that converts the energy of light directly into electricity by the photovoltaic effect....

 to record and reproduce sound signals that were optically recorded directly onto the movie film. The introduction of talking movies, spearheaded by The Jazz Singer
The Jazz Singer (1927 film)
The Jazz Singer is a 1927 American musical film. The first feature-length motion picture with synchronized dialogue sequences, its release heralded the commercial ascendance of the "talkies" and the decline of the silent film era. Produced by Warner Bros. with its Vitaphone sound-on-disc system,...

in 1927 (though it used a sound on disk technique, not a photoelectric one), saw the rapid demise of live cinema musicians and orchestras. They were replaced with pre-recorded soundtracks, causing the loss of many jobs. The American Federation of Musicians
American Federation of Musicians
The American Federation of Musicians of the United States and Canada is a labor union of professional musicians in the United States and Canada...

 took out ads in newspapers, protesting the replacement of real musicians with mechanical playing devices, especially in theatres.

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
Valdemar Poulsen
Valdemar Poulsen was a Danish engineer who developed a magnetic wire recorder in 1899.-Biography:He was born on 23 November 1869 in Copenhagen...

. 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
Guglielmo Marconi
Guglielmo Marconi was an Italian inventor, known as the father of long distance radio transmission and for his development of Marconi's law and a radio telegraph system. Marconi is often credited as the inventor of radio, and indeed he shared the 1909 Nobel Prize in Physics with Karl Ferdinand...

 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 K1 Magnetophon
Magnetophon
Magnetophon was the brand or model name of the pioneering reel-to-reel tape recorder developed by engineers of the German electronics company AEG in the 1930s, based on the magnetic tape invention by Fritz Pfleumer...

 was the first practical tape recorder, developed by AEG in Germany in 1935. The other major invention in sound recording in this period was the optical sound-on-film
Sound-on-film
Sound-on-film refers to a class of sound film processes where the sound accompanying picture is physically recorded onto photographic film, usually, but not always, the same strip of film carrying the picture. Sound-on-film processes can either record an analog sound track or digital sound track,...

 system, also generally credited to Lee De Forest. Although famous early "Talkies" like The Jazz Singer
The Jazz Singer (1927 film)
The Jazz Singer is a 1927 American musical film. The first feature-length motion picture with synchronized dialogue sequences, its release heralded the commercial ascendance of the "talkies" and the decline of the silent film era. Produced by Warner Bros. with its Vitaphone sound-on-disc system,...

used a sound-on-disc system, the film industry rapidly 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 and remains so for theatrical release prints despite attempts in the 1950s to substitute magnetic recording methods. Currently all release prints on 35mm film include an analogue optical soundtrack (usually stereo with Dolby SR noise reduction). In addition an optically recorded digital soundtrack in Dolby Digital and/or Sony SDDS form is likely to be present. Optically recorded timecode is also commonly found in order to synchronise CDROMs containing a DTS soundtrack.

Magnetic tape

Other important inventions of this period were magnetic tape
Magnetic tape
Magnetic tape is a medium for magnetic recording, made of a thin magnetizable coating on a long, narrow strip of plastic. It was developed in Germany, based on magnetic wire recording. Devices that record and play back audio and video using magnetic tape are tape recorders and video tape recorders...

 and the tape recorder
Tape recorder
An audio tape recorder, tape deck, reel-to-reel tape deck, cassette deck or tape machine is an audio storage device that records and plays back sounds, including articulated voices, usually using magnetic tape, either wound on a reel or in a cassette, for storage...

 (Telegraphone). 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 with the help of Crosby Enterprises (Bing Crosby
Bing Crosby
Harry Lillis "Bing" Crosby was an American singer and actor. Crosby's trademark bass-baritone voice made him one of the best-selling recording artists of the 20th century, with over half a billion records in circulation....

), whose pioneering recorders were based on captured German recorders, and the Ampex
Ampex
Ampex is an American electronics company founded in 1944 by Alexander M. Poniatoff. The name AMPEX is an acronym, created by its founder, which stands for Alexander M. Poniatoff Excellence...

 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
Les Paul
Lester William Polsfuss —known as Les Paul—was an American jazz and country guitarist, songwriter and inventor. He was a pioneer in the development of the solid-body electric guitar which made the sound of rock and roll possible. He is credited with many recording innovations...

 had invented the first multitrack tape recorder, ushering in 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
Musique concrète
Musique concrète is a form of electroacoustic music that utilises acousmatic sound as a compositional resource. The compositional material is not restricted to the inclusion of sounds derived from musical instruments or voices, nor to elements traditionally thought of as "musical"...

 school and avant garde composers like Karlheinz Stockhausen
Karlheinz Stockhausen
Karlheinz Stockhausen was a German composer, widely acknowledged by critics as one of the most important but also controversial composers of the 20th and early 21st centuries. Another critic calls him "one of the great visionaries of 20th-century music"...

, which in turn led to the innovative pop music recordings of artists such as Frank Zappa
Frank Zappa
Frank Vincent Zappa was an American composer, singer-songwriter, electric guitarist, record producer and film director. In a career spanning more than 30 years, Zappa wrote rock, jazz, orchestral and musique concrète works. He also directed feature-length films and music videos, and designed...

, The Beatles
The Beatles
The Beatles were an English rock band, active throughout the 1960s and one of the most commercially successful and critically acclaimed acts in the history of popular music. Formed in Liverpool, by 1962 the group consisted of John Lennon , Paul McCartney , George Harrison and Ringo Starr...

 and The Beach Boys
The Beach Boys
The Beach Boys are an American rock band, formed in 1961 in Hawthorne, California. The group was initially composed of brothers Brian, Dennis and Carl Wilson, their cousin Mike Love, and friend Al Jardine. Managed by the Wilsons' father Murry, The Beach Boys signed to Capitol Records in 1962...

.

Magnetic tape allowed 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. Also, for the first time, broadcasters, regulators and other interested parties were able to undertake comprehensive logging of radio broadcasts. Innovations like multitracking and tape echo
Delay (audio effect)
Delay is an audio effect which records an input signal to an audio storage medium, and then plays it back after a period of time. The delayed signal may either be played back multiple times, or played back into the recording again, to create the sound of a repeating, decaying echo.-Early delay...

 enabled radio programs and advertisements to be pre-produced to a level of complexity and sophistication that was previously unattainable and the combined impact of these new techniques led to significant changes to the pacing and production style of program content, thanks to the innovations like the endless-loop broadcast cartridge.

Stereo and hi-fi

In 1881, it was noted during experiments in transmitting sound from the Paris Opera that it was possible to follow the movement of singers on the stage if earpieces connected to different microphones were held to the two ears. This discovery was commercialized in 1890 with the Théâtrophone
Théâtrophone
Théâtrophone was a telephonic distribution system that allowed the subscribers to listen to opera and theatre performances over the telephone lines. The théâtrophone evolved from a Clément Ader invention, which was first demonstrated in 1881, in Paris...

 system, which operated for over forty years until 1932.

In 1931 Alan Blumlein
Alan Blumlein
Alan Dower Blumlein was a British electronics engineer, notable for his many inventions in telecommunications, sound recording, stereo, television and radar...

, a British electronics engineer working for EMI
EMI
The EMI Group, also known as EMI Music or simply EMI, is a multinational music company headquartered in London, United Kingdom. It is the fourth-largest business group and family of record labels in the recording industry and one of the "big four" record companies. EMI Group also has a major...

, designed a way to make the sound of an actor in a film follow their movement across the screen. In December 1931 he submitted a patent including the idea, and in 1933 this became UK
United Kingdom
The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...

 patent number 394,325. Over the next two years, Blumlein developed stereo microphones and a stereo disc-cutting head, and recorded a number of short films with stereo soundtracks.

Magnetic tape enabled the development of the first practical commercial sound systems that could record and reproduce high-fidelity stereophonic sound
Stereophonic sound
The term Stereophonic, commonly called stereo, sound refers to any method of sound reproduction in which an attempt is made to create an illusion of directionality and audible perspective...

. The experiments with stereo during the 1930s and 1940s were hampered by problems with synchronization. A 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 for a commercial film was made by Judy Garland
Judy Garland
Judy Garland was an American actress and singer. Through a career that spanned 45 of her 47 years and for her renowned contralto voice, she attained international stardom as an actress in musical and dramatic roles, as a recording artist and on the concert stage...

 for the MGM movie Listen, Darling in 1938.

The first movie commercially released with a stereo soundtrack was Walt Disney's Fantasia
Fantasia (film)
Fantasia is a 1940 American animated film produced by Walt Disney and released by Walt Disney Productions. The third feature in the Walt Disney Animated Classics series, the film consists of eight animated segments set to pieces of classical music conducted by Leopold Stokowski, seven of which are...

, released in 1940. The original 1941 release of this production used the "Fantasound
Fantasound
Fantasound was a stereophonic sound reproduction system developed by the engineers of Walt Disney studios for its 1940 animated film Fantasia, the first commercial film to be released in stereo. Fantasound led to the development of what is known today as surround sound.-Origins:Walt Disney's...

" sound system. This system employed a separate film for the sound, which ran in synchronism with the film carrying the picture. On this sound film were four double-width optical soundtracks, three of which carried left, center and right audio while the fourth was a "control" track on which were recorded three tones which controlled the playback volume of the three audio channels.
Because of the complex equipment required to present it, it was shown as a roadshow, but only in the United States. Regular releases of the film were on standard mono optical 35 mm stock until 1956 when the film was released with a stereo soundtrack using the "Cinemascope
CinemaScope
CinemaScope was an anamorphic lens series used for shooting wide screen movies from 1953 to 1967. Its creation in 1953, by the president of 20th Century-Fox, marked the beginning of the modern anamorphic format in both principal photography and movie projection.The anamorphic lenses theoretically...

" four-track magnetic sound system.

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
Ampex
Ampex is an American electronics company founded in 1944 by Alexander M. Poniatoff. The name AMPEX is an acronym, created by its founder, which stands for Alexander M. Poniatoff Excellence...

 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. This changed after the late 1957 introduction of the "Westrex stereo phonograph disc", which used the groove format developed earlier by Blumlein. Decca Records
Decca Records
Decca Records began as a British record label established in 1929 by Edward Lewis. Its U.S. label was established in late 1934; however, owing to World War II, the link with the British company was broken for several decades....

 in England came out with FFRR (Full Frequency Range Recording) in the 1940s which became internationally accepted and a worldwide standard for higher quality recordings on vinyl records. The Ernest Ansermet
Ernest Ansermet
Ernest Alexandre Ansermet was a Swiss conductor.- Biography :Ansermet was born in Vevey, Switzerland. Although he was a contemporary of Wilhelm Furtwängler and Otto Klemperer, Ansermet represents in most ways a very different tradition and approach from those two musicians. Originally he was a...

 recording of Igor Stravinsky
Igor Stravinsky
Igor Fyodorovich Stravinsky ; 6 April 1971) was a Russian, later naturalized French, and then naturalized American composer, pianist, and conductor....

's Petrushka was key in the development of full frequency range records and alerting the listening public to high fidelity in 1946.

Most pop singles were mixed into monophonic sound until the mid 1960s, and 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 mid Sixties, as stereo became more popular, many mono recordings (such as The Beach Boys' Pet Sounds
Pet Sounds
Pet Sounds is the eleventh studio album by the American rock band The Beach Boys, released May 16, 1966, on Capitol Records. It has since been recognized as one of the most influential records in the history of popular music and one of the best albums of the 1960s, including songs such as "Wouldn't...

) 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.

1950s to 1980s

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
Transistor
A transistor is a semiconductor device used to amplify and switch electronic signals and power. It is composed of a semiconductor material with at least three terminals for connection to an external circuit. A voltage or current applied to one pair of the transistor's terminals changes the current...

 brought other radical changes, the most important of which was the introduction of the world's first "personal music device", the miniaturized transistor radio
Transistor radio
A transistor radio is a small portable radio receiver using transistor-based circuitry. Following their development in 1954 they became the most popular electronic communication device in history, with billions manufactured during the 1960s and 1970s...

, which became a major consumer luxury item in the 1960s, transforming radio broadcasting from a static group experience into a mobile, personal listening activity. An early multitrack recording made using magnetic tape
Magnetic tape
Magnetic tape is a medium for magnetic recording, made of a thin magnetizable coating on a long, narrow strip of plastic. It was developed in Germany, based on magnetic wire recording. Devices that record and play back audio and video using magnetic tape are tape recorders and video tape recorders...

 was "How High the Moon
How High the Moon
"How High the Moon" is a jazz standard with lyrics by Nancy Hamilton and music by Morgan Lewis. It was first featured in the 1940 Broadway revue Two for the Show, where it was sung by Alfred Drake and Frances Comstock....

" by Les Paul
Les Paul
Lester William Polsfuss —known as Les Paul—was an American jazz and country guitarist, songwriter and inventor. He was a pioneer in the development of the solid-body electric guitar which made the sound of rock and roll possible. He is credited with many recording innovations...

, on which Paul played eight overdubbed guitar tracks. In the 1960s Brian Wilson
Brian Wilson
Brian Douglas Wilson is an American musician, best known as the leader and chief songwriter of the group The Beach Boys. Within the band, Wilson played bass and keyboards, also providing part-time lead vocals and, more often, backing vocals, harmonizing in falsetto with the group...

 of The Beach Boys
The Beach Boys
The Beach Boys are an American rock band, formed in 1961 in Hawthorne, California. The group was initially composed of brothers Brian, Dennis and Carl Wilson, their cousin Mike Love, and friend Al Jardine. Managed by the Wilsons' father Murry, The Beach Boys signed to Capitol Records in 1962...

, Frank Zappa
Frank Zappa
Frank Vincent Zappa was an American composer, singer-songwriter, electric guitarist, record producer and film director. In a career spanning more than 30 years, Zappa wrote rock, jazz, orchestral and musique concrète works. He also directed feature-length films and music videos, and designed...

 and The Beatles
The Beatles
The Beatles were an English rock band, active throughout the 1960s and one of the most commercially successful and critically acclaimed acts in the history of popular music. Formed in Liverpool, by 1962 the group consisted of John Lennon , Paul McCartney , George Harrison and Ringo Starr...

 (with producer George Martin
George Martin
Sir George Henry Martin CBE is an English record producer, arranger, composer and musician. He is sometimes referred to as "the Fifth Beatle"— a title that he often describes as "nonsense," but the fact remains that he served as producer on all but one of The Beatles' original albums...

) were among the first popular artists to explore the possibilities of multitrack recording
Multitrack recording
Multitrack recording is a method of sound recording that allows for the separate recording of multiple sound sources to create a cohesive whole...

 techniques and effects on their landmark albums Pet Sounds
Pet Sounds
Pet Sounds is the eleventh studio album by the American rock band The Beach Boys, released May 16, 1966, on Capitol Records. It has since been recognized as one of the most influential records in the history of popular music and one of the best albums of the 1960s, including songs such as "Wouldn't...

, Freak Out!
Freak Out!
Freak Out! is the debut album by American band The Mothers of Invention, released June 27, 1966 on Verve Records. Often cited as one of rock music's first concept albums, the album is a satirical expression of frontman Frank Zappa's perception of American pop culture...

and Sgt. Pepper's Lonely Hearts Club Band
Sgt. Pepper's Lonely Hearts Club Band
Sgt. Pepper's Lonely Hearts Club Band is the eighth studio album by the English rock band The Beatles, released on 1 June 1967 on the Parlophone label and produced by George Martin...

.

The next important innovation was small cartridge based tape systems of which the compact cassette
Compact Cassette
The Compact Cassette, often referred to as audio cassette, cassette tape, cassette, or simply tape, is a magnetic tape sound recording format. It was designed originally for dictation, but improvements in fidelity led the Compact Cassette to supplant the Stereo 8-track cartridge and reel-to-reel...

, introduced by the Philips
Philips
Koninklijke Philips Electronics N.V. , more commonly known as Philips, is a multinational Dutch electronics company....

 electronics company in 1964 is the best known. It eventually entirely replaced the competing formats, the larger 8-track tape (used primarily in cars) and the fairly similar 'Deutsche Cassette' developed by the German company Grundig. This latter system was not particularly common in Europe and practically unheard of in America. The compact cassette became a major consumer audio format and advances in microelectronics
Microelectronics
Microelectronics is a subfield of electronics. As the name suggests, microelectronics relates to the study and manufacture of very small electronic components. Usually, but not always, this means micrometre-scale or smaller,. These devices are made from semiconductors...

 eventually allowed the development of the Sony
Sony
, commonly referred to as Sony, is a Japanese multinational conglomerate corporation headquartered in Minato, Tokyo, Japan and the world's fifth largest media conglomerate measured by revenues....

 Walkman
Walkman
Walkman is a Sony brand tradename originally used for portable audio cassette, and now used to market Sony's portable audio and video players as well as a line of Sony Ericsson mobile phones...

, introduced in the 1970s, which was the first personal music player and gave a major boost to the mass distribution of music recordings. Cassettes became the first successful consumer recording/re-recording medium. The gramophone record was a pre-recorded playback only medium, and reel-to-reel audio tape recording
Reel-to-reel audio tape recording
Reel-to-reel, open reel tape recording is the form of magnetic tape audio recording in which the recording medium is held on a reel, rather than being securely contained within a cassette....

 magnetic tape
Magnetic tape
Magnetic tape is a medium for magnetic recording, made of a thin magnetizable coating on a long, narrow strip of plastic. It was developed in Germany, based on magnetic wire recording. Devices that record and play back audio and video using magnetic tape are tape recorders and video tape recorders...

 was too difficult for most consumers and far less portable.

A key advance in audio fidelity came with the Dolby A noise reduction system, invented by Ray Dolby
Ray Dolby
Ray Dolby is the American engineer and inventor of the noise reduction system known as Dolby NR. He was also a co-inventor of video tape recording while at Ampex. He is the founder of Dolby Laboratories.-Biography:...

 and introduced in 1966. A competing system dbx
Dbx (noise reduction)
dbx is a family of noise reduction systems developed by the company of the same name. The most common implementations are dbx Type I and dbx Type II for analog tape recording and, less commonly, vinyl LPs. A separate implementation, known as dbx-TV, is part of the MTS system used to provide stereo...

, invented by David Blackmer, found most success in professional audio. A simpler variant of Dolby's noise reduction system, known as Dolby B greatly improved the sound of cassette tape recordings by reducing the practical effect of the recorded hiss inherent in the narrow tape used. It, and variants, also eventually found wide application in the recording and film industries. Dolby B 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 compact cassette also benefited enormously from developments in the tape material itself as materials with wider frequency responses and lower inherent noise were developed, often based on cobalt and/or chrome oxides as the magnetic material instead of the more usual iron oxide.

The multitrack audio cartridge had been in wide use in the radio industry, from the late 1950s to the 1980s, but in the 1960s the pre-recorded 8-track cartridge
8-track cartridge
Stereo 8, commonly known as the eight-track cartridge, eight-track tape, or simply eight-track, is a magnetic tape sound recording technology. It was popular in the United States from the mid-1960s through the late 1970s, but was relatively unknown in many European countries...

 was launched as a consumer audio format by Bill Lear
Bill Lear
William Powell Lear was an American inventor and businessman. He is best known for founding the Lear Jet Corporation, a manufacturer of business jets...

 of the Lear Jet aircraft company (and although its correct name was the 'Lear Jet Cartridge', it was seldom referred to as such). Aimed particularly at the automotive market, they were the first practical, affordable car hi-fi systems, and could produce superior sound quality to the compact cassette. However the smaller size and greater durability — augmented by the ability to create home-recorded music "compilations" since 8-track recorders were rare — 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
Quadraphonic
Quadraphonic sound – the most widely used early term for what is now called 4.0 surround sound – uses four channels in which speakers are positioned at the four corners of the listening space, reproducing signals that are independent of one another...

 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 one of the competing four-channel formats; among the best known are Mike Oldfield
Mike Oldfield
Michael Gordon Oldfield is an English multi-instrumentalist musician and composer, working a style that blends progressive rock, folk, ethnic or world music, classical music, electronic music, New Age, and more recently, dance. His music is often elaborate and complex in nature...

's Tubular Bells
Tubular Bells
Tubular Bells is the debut record album of English musician Mike Oldfield, released in 1973. It was the first album released by Virgin Records and an early cornerstone of the company's success...

and Pink Floyd
Pink Floyd
Pink Floyd were an English rock band that achieved worldwide success with their progressive and psychedelic rock music. Their work is marked by the use of philosophical lyrics, sonic experimentation, innovative album art, and elaborate live shows. Pink Floyd are one of the most commercially...

's The Dark Side of the Moon
The Dark Side of the Moon
The Dark Side of the Moon is the eighth studio album by English progressive rock band Pink Floyd, released in March 1973. It built on ideas explored in the band's earlier recordings and live shows, but lacks the extended instrumental excursions that characterised their work following the departure...

. Quadraphonic sound was not a commercial success, partly because of competing and somewhat incompatible four-channel sound systems (e.g., CBS
CBS
CBS Broadcasting Inc. is a major US commercial broadcasting television network, which started as a radio network. The name is derived from the initials of the network's former name, Columbia Broadcasting System. The network is sometimes referred to as the "Eye Network" in reference to the shape of...

, JVC
JVC
, usually referred to as JVC, is a Japanese international consumer and professional electronics corporation based in Yokohama, Japan which was founded in 1927...

, Dynaco
Dynaco
Founded by David Hafler and Ed Laurent in Philadelphia, Pennsylvania in 1955, Dynaco was an American hi-fi audio system manufacturer popular in the 1960s and 1970s for its wide range of affordable, yet high quality audio components..-Early company history:...

 and others all had systems) and generally poor quality, even when played as intended on the correct equipment, of the released music. It eventually faded out in the late 1970s, although this early venture paved the way for the eventual introduction of domestic Surround Sound
Surround sound
Surround sound encompasses a range of techniques such as for enriching the sound reproduction quality of an audio source with audio channels reproduced via additional, discrete speakers. Surround sound is characterized by a listener location or sweet spot where the audio effects work best, and...

 systems in home theatre use, which have gained enormous popularity since the introduction of the DVD. This widespread adoption has occurred despite the confusion introduced by the multitude of available surround sound standards.

Audio components

The replacement of the thermionic valve (vacuum tube) 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 most record players were monophonic and had relatively low sound quality; few consumers could afford high-quality stereophonic sound systems. In the 1960s, American manufacturers introduced a new generation of "modular" hi-fi components — separate turntables, pre-amplifiers, amplifiers, both combined as 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 Japanese electronics companies, which soon flooded the world market with relatively cheap, high-quality components. By the 1980s, corporations like Sony
Sony
, commonly referred to as Sony, is a Japanese multinational conglomerate corporation headquartered in Minato, Tokyo, Japan and the world's fifth largest media conglomerate measured by revenues....

 had become world leaders in the music recording and playback industry.

Digital recording

The invention of digital sound recording
Digital recording
In digital recording, digital audio and digital video is directly recorded to a storage device as a stream of discrete numbers, representing the changes in air pressure for audio and chroma and luminance values for video through time, thus making an abstract template for the original sound or...

 and later the compact disc in 1982 brought significant improvements in the durability of consumer recordings. The CD initiated another massive wave of change in the consumer music industry, with vinyl records
Gramophone record
A gramophone record, commonly known as a phonograph record , vinyl record , or colloquially, a record, is an analog sound storage medium consisting of a flat disc with an inscribed, modulated spiral groove...

 effectively relegated to a small niche market by the mid-1990s. However, the introduction of digital systems was initially fiercely resisted by the record industry which feared wholesale piracy on a medium which was able to produce perfect copies of original released recordings. However, the industry had to bow to the inevitable, but not without using various protection system (principally Serial Copy Management System
Serial Copy Management System
The Serial Copy Management System or SCMS is a copy protection scheme that was created in response to the digital audio tape invention, in order to prevent DAT recorders from making second-generation or serial copies. SCMS sets a "copy" bit in all copies, which prevents anyone from making further...

, or SCMS).
The most recent and revolutionary developments have been in digital recording, with the development of various uncompressed and compressed digital audio file format
Audio file format
An audio file format is a file format for storing digital audio data on a computer system. This data can be stored uncompressed, or compressed to reduce the file size. It can be a raw bitstream, but it is usually a container format or an audio data format with defined storage layer.-Types of...

s, processors
Microprocessor
A microprocessor incorporates the functions of a computer's central processing unit on a single integrated circuit, or at most a few integrated circuits. It is a multipurpose, programmable device that accepts digital data as input, processes it according to instructions stored in its memory, and...

 capable and fast enough to convert the digital data to sound in real time
Real-time computing
In computer science, real-time computing , or reactive computing, is the study of hardware and software systems that are subject to a "real-time constraint"— e.g. operational deadlines from event to system response. Real-time programs must guarantee response within strict time constraints...

, and inexpensive mass storage
Mass storage
In computing, mass storage refers to the storage of large amounts of data in a persisting and machine-readable fashion. Devices and/or systems that have been described as mass storage include tape libraries, RAID systems, hard disk drives, magnetic tape drives, optical disc drives, magneto-optical...

. This generated a new type of portable digital audio player. The minidisc
MiniDisc
The disc is permanently housed in a cartridge with a sliding door, similar to the casing of a 3.5" floppy disk. This shutter is opened automatically by a mechanism upon insertion. The audio discs can either be recordable or premastered. Recordable MiniDiscs use a magneto-optical system to record...

 player, using ATRAC
ATRAC
Adaptive Transform Acoustic Coding is a family of proprietary audio compression algorithms developed by Sony. MiniDisc was the first commercial product to incorporate ATRAC in 1992. ATRAC allowed a relatively small disc like MiniDisc to have the same running time as CD while storing audio...

 compression on small, cheap, re-writeable discs was introduced in the 1990s but became obsolescent as solid-state non-volatile flash memory
Flash memory
Flash memory is a non-volatile computer storage chip that can be electrically erased and reprogrammed. It was developed from EEPROM and must be erased in fairly large blocks before these can be rewritten with new data...

 dropped in price. As technologies which increase the amount of data that can be stored on a single medium, such as Super Audio CD
Super Audio CD
Super Audio CD is a high-resolution, read-only optical disc for audio storage. Sony and Philips Electronics jointly developed the technology, and publicized it in 1999. It is designated as the Scarlet Book standard. Sony and Philips previously collaborated to define the Compact Disc standard...

, DVD-A, Blu-ray Disc
Blu-ray Disc
Blu-ray Disc is an optical disc storage medium designed to supersede the DVD format. The plastic disc is 120 mm in diameter and 1.2 mm thick, the same size as DVDs and CDs. Blu-ray Discs contain 25 GB per layer, with dual layer discs being the norm for feature-length video discs...

 and HD DVD
HD DVD
HD DVD is a discontinued high-density optical disc format for storing data and high-definition video.Supported principally by Toshiba, HD DVD was envisioned to be the successor to the standard DVD format...

 become available, longer programs of higher quality fit onto a single disc. Sound files are readily downloaded from the Internet and other sources, and copied onto computers and digital audio players. Digital audio technology is used in all areas of audio, from casual use of music files of moderate quality to the most demanding professional applications. New applications such as internet radio
Internet radio
Internet radio is an audio service transmitted via the Internet...

 and podcasting
Podcasting
A podcast is a series of digital media files that are released episodically and often downloaded through web syndication...

 have appeared.

Technological developments in recording and editing have transformed the record, movie
Film industry
The film industry consists of the technological and commercial institutions of filmmaking: i.e. film production companies, film studios, cinematography, film production, screenwriting, pre-production, post production, film festivals, distribution; and actors, film directors and other film crew...

 and television industries in recent decades. Audio editing
Audio engineering
An audio engineer, also called audio technician, audio technologist or sound technician, is a specialist in a skilled trade that deals with the use of machinery and equipment for the recording, mixing and reproduction of sounds. The field draws on many artistic and vocational areas, including...

 became practicable with the invention of magnetic tape recording, but digital audio and cheap mass storage
Mass storage
In computing, mass storage refers to the storage of large amounts of data in a persisting and machine-readable fashion. Devices and/or systems that have been described as mass storage include tape libraries, RAID systems, hard disk drives, magnetic tape drives, optical disc drives, magneto-optical...

 allows computers to edit audio files quickly, easily, and cheaply. Today, the process of making a recording is separated into tracking, mixing
Audio mixing (recorded music)
In audio recording, audio mixing is the process by which multiple recorded sounds are combined into one or more channels, most commonly two-channel stereo. In the process, the source signals' level, frequency content, dynamics, and panoramic position are manipulated and effects such as reverb may...

 and mastering
Audio mastering
Mastering, a form of audio post-production, is the process of preparing and transferring recorded audio from a source containing the final mix to a data storage device ; the source from which all copies will be produced...

. Multitrack recording
Multitrack recording
Multitrack recording is a method of sound recording that allows for the separate recording of multiple sound sources to create a cohesive whole...

 makes it possible to capture signals from several microphones, or from different 'takes' to tape or disc, with maximized headroom and quality, allowing previously unavailable flexibility in the mixing and mastering stages for editing, level balancing, compressing
Audio level compression
Dynamic range compression, also called DRC or simply compression reduces the volume of loud sounds or amplifies quiet sounds by narrowing or "compressing" an audio signal's dynamic range...

 and limiting
Limiter
In electronics, a limiter is a circuit that allows signals below a specified input power to pass unaffected while attenuating the peaks of stronger signals that exceed this input power....

, adding effects such as reverberation
Reverberation
Reverberation is the persistence of sound in a particular space after the original sound is removed. A reverberation, or reverb, is created when a sound is produced in an enclosed space causing a large number of echoes to build up and then slowly decay as the sound is absorbed by the walls and air...

, equalisation
Equalization (audio)
Equalization is the process commonly used in sound recording and reproduction to alter the frequency response of an audio system using linear filters. Most hi-fi equipment uses relatively simple filters to make bass and treble adjustments. Graphic and parametric equalizers have much more...

, flanging
Flanging
Flanging is an audio effect produced by mixing two identical signals together, with one signal delayed by a small and gradually changing period, usually smaller than 20 milliseconds. This produces a swept comb filter effect: peaks and notches are produced in the resultant frequency spectrum,...

, and much more.

Digital recording and processing software

There are many different digital audio recording and processing programs running under several computer operating system
Operating system
An operating system is a set of programs that manage computer hardware resources and provide common services for application software. The operating system is the most important type of system software in a computer system...

s for all purposes, from professional through serious amateur to casual user.

A comprehensive list of digital recording applications is available on the digital audio workstation
Digital audio workstation
A digital audio workstation is an electronic system designed solely or primarily for recording, editing and playing back digital audio. DAWs were originally tape-less, microprocessor-based systems such as the Synclavier and Fairlight CMI...

 page.

Digital dictation
Digital dictation
Digital dictation is a method of recording and editing the spoken word in real-time for transcription and maximum intelligibility in a digital audio format...

 software for recording and transcribing speech has different requirements; intelligibility and flexible playback facilities are priorities, while a wide frequency range and high audio quality are not.

Voice to note

Voice-to-note refers to the capability of personal computers to be able to recognize notes that are sung, hummed, or whistled into a microphone
Microphone
A microphone is an acoustic-to-electric transducer or sensor that converts sound into an electrical signal. In 1877, Emile Berliner invented the first microphone used as a telephone voice transmitter...

. The pitch
Pitch (music)
Pitch is an auditory perceptual property that allows the ordering of sounds on a frequency-related scale.Pitches are compared as "higher" and "lower" in the sense associated with musical melodies,...

 and duration of the notes are then calculated and converted into MIDI music files.

UK

Since 1934, sound recordings are treated differently from musical works under copyright law. Copyright, Designs and Patents Act 1988
Copyright, Designs and Patents Act 1988
The Copyright, Designs and Patents Act 1988 , also known as the CDPA, is an Act of the Parliament of the United Kingdom which received Royal Assent on 15 November 1988. It reformulates almost completely the statutory basis of copyright law in the United Kingdom, which had, until then, been...

defines a sound recording to mean (a) a recording of sounds, from which the sounds may be reproduced, or (b) a recording of the whole or any part of a literary, dramatic or musical work, from which sounds reproducing the work or part may be produced, regardless of the medium on which the recording is made or the method by which the sounds are reproduced or produced. It thus covers vinyl records, tapes, compact discs, digital audiotapes, and MP3s which embody recordings.

Further reading

  • Carson, B. H.; Burt, A. D.; Reiskind, and H. I., "A Record Changer And Record Of Complementary Design", RCA Review, June 1949
  • Coleman, Mark, Playback: from the Victrola to MP3, 100 years of music, machines, and money, Da Capo Press, 2003.
  • Gaisberg, Frederick W.
    Fred Gaisberg
    Frederick William Gaisberg was an American-born musician, recording engineer and one of the earliest classical music producers for the gramophone. He himself did not use the term 'producer' and was not an impresario like his protégé Walter Legge of EMI or an innovator like John Culshaw of Decca...

    , "The Music Goes Round", [Andrew Farkas, editor.], New Haven, Ayer, 1977.
  • Gronow, Pekka, "The Record Industry: The Growth of a Mass Medium", Popular Music, Vol. 3, Producers and Markets (1983), pp. 53–75, Cambridge University Press.
  • Gronow, Pekka, and Saunio, Ilpo, "An International History of the Recording Industry", [translated from the Finnish by Christopher Moseley], London ; New York : Cassell, 1998. ISBN 0304701734
  • Lipman, Samuel,"The House of Music: Art in an Era of Institutions", 1984. See the chapter on "Getting on Record", pp. 62–75, about the early record industry and Fred Gaisberg and Walter Legge
    Walter Legge
    Harry Walter Legge was an influential English classical record producer, most notably for EMI. His recordings include many sets later regarded as classics and reissued by EMI as "Great Recordings of the Century". He worked in the recording industry from 1927, combining this with the post of junior...

     and FFRR (Full Frequency Range Recording).
  • Millard, Andre J., "America on record : a history of recorded sound", Cambridge ; New York : Cambridge University Press, 1995. ISBN 0521475449
  • Millard, Andre J., " From Edison to the iPod", UAB Reporter, 2005, University of Alabama at Birmingham
    University of Alabama at Birmingham
    The University of Alabama at Birmingham is a public university in Birmingham in the U.S. state of Alabama. Developing from an extension center established in 1936, the institution became an autonomous institution in 1969 and is today one of three institutions in the University of Alabama System...

    .
  • Milner, Greg, "Perfecting Sound Forever: An Aural History of Recorded Music", Faber & Faber; 1 edition (June 9, 2009) ISBN 978-0571211654. Cf. p. 14 on H. Stith Bennett and "recording consciousness".
  • "Recording Technology History: notes revised July 6, 2005, by Steven Schoenherr", San Diego University
    University of San Diego
    The University of San Diego is a Roman Catholic university in San Diego, California. USD offers more than sixty bachelor's, master’s, and doctoral programs...

     (archived 2010)

Media


External links

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