Sound recording and reproduction（1）

Sound recording and reproduction is an electrical or mechanical inscription and re-creation of sound waves, such as spoken voice, singing, instrumental music, or sound effects(SONY Vaio VGN-FW31J Battery). The two main classes of sound recording technology are analog recording and digital recording. Acoustic analog recording is achieved by a small microphone diaphragm that can detect changes in atmospheric pressure (acoustic sound waves) (SONY Vaio VGN-FW32J Battery)and record them as a graphic representation of the sound waves on a medium such as a phonograph (in which a stylus senses grooves on a record) (SONY Vaio VGN-FW17W Battery). In magnetic tape recording, the sound waves vibrate the microphone diaphragm and are converted into a varying electric current, which is then converted to a varying magnetic field by an electromagnet(SONY Vaio VGN-FW31E Battery), 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 diaphragm causing changes to atmospheric pressure to form acoustic sound waves(SONY Vaio VGN-FW139E Battery). Electronically generated sound waves may also be recorded directly from devices such as an electric guitar pickup or a synthesizer, 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(SONY Vaio VGN-FW139E/H Battery).

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 by a wider variety of media(SONY Vaio VGN-FW465J Battery). Digital recording stores audio as a series of binary numbers representing samples of the amplitude of the audio signal at equal time intervals, at a sample rate so fast that the human ear perceives the result as continuous sound(SONY Vaio VGN-FW31M Battery). Digital recordings are considered higher quality than analog recordings not necessarily because they have higher fidelity (wider frequency response or dynamic range) (SONY VAIO VGN-FZ21E Battery), but because the digital format can prevent much loss of quality found in analog recording due to noise and electromagnetic interference in playback, and mechanical deterioration or damage to the storage medium. A digital audio signal must be reconverted to analog form during playback before it is applied to a loudspeaker or earphones(SONY VAIO VGN-FZ21Z Battery).

History

Origins

435 HZ

This 1859 phonautogram by Édouard-Léon Scott de Martinville is the earliest known modern sound recording(SONY VAIO VGN-FZ21J Battery).

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Au Clair de la Lune

This 1860 phonautogram by Édouard-Léon Scott de Martinville is the first known sound recording with a human voice.

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The automatic reproduction of music can be traced back as far as the 9th century, when the Banū Mūsā brothers invented "the earliest known mechanical musical instrument", in this case a hydropowered organ which played interchangeable cylinders automatically(SONY Vaio VGN-FW11M Battery). 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 also invented an automatic flute player which appears to have been the first programmable machine(SONY Vaio VGN-FW11S Battery).

In the 14th century, Flanders introduced a mechanical bell-ringer controlled by a rotating cylinder. Similar designs appeared in barrel organs (15th century), musical clocks (1598), barrel pianos (1805), and musical boxes (1815) (SONY Vaio VGN-FW21E Battery).

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. The first device that could record sound mechanically (but could not play it back) was the phonautograph(SONY Vaio VGN-FW21J Battery), developed in 1857 by Parisian inventor Édouard-Léon Scott de Martinville. 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(SONY Vaio VGN-FW21L Battery). 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.[4] One of his phonautograms of Au Clair de la Lune, a French folk song, was digitally converted to sound in 2008(SONY Vaio VGN-FW21M Battery). While this is an interesting playback that sounds like a girl singing, the creator of this recording, Patrick Feaster of Indiana University in Bloomington, reports that phonautograms his team had previously transcribed, using a laser as a virtual stylus, had been played back at twice the actual speed(SONY VGP-BPS13Q Battery). What sounded like a girl singing the French folksong was actually Léon Scott singing, Feaster concluded in May, 2009. Since the above recording was recovered, the same team have since recovered a recording of a 435-Hz tuning fork (at that time the French standard concert pitch for A' — now 440 Hz). The tuning fork is barely audible(SONY VGP-BPS13B/Q Battery).

The player piano, first demonstrated in 1876, used a punched paper scroll that could store an arbitrarily long piece of music. This piano roll moved over a device known as the 'tracker bar', which first had 58 holes, was expanded to 65 and then was upgraded to 88 holes (generally, one for each piano key) (SONY VGN NR11S/S battery). When a perforation passed over the hole, the note sounded. Piano rolls were the first stored music medium that could be mass-produced, although the hardware to play them was much too expensive for personal use(SONY VGN NR11M/S battery). 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(SONY VGN NR11Z/S battery), 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(SONY VGN NR11Z/T battery). The fairground organ, developed in 1892, used a similar system of accordion-folded punched cardboard books.

Phonograph

Main article: Phonograph

Phonograph cylinder

Frances Densmore recording Blackfoot chief Mountain Chief on a cylinder phonograph for the Bureau of American Ethnology (1916) (SONY VGP-BPS13A/Q Battery)

"Kham Hom" ("Sweet Words")

Phonograph cylinder recording of Siamese (Thai) musicians visiting Berlin, Germany in 1900.

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The first practical sound recording and reproduction device was the mechanical phonograph cylinder, invented by Thomas Edison in 1877 and patented in 1878. The invention soon spread across the globe and over the next two decades the commercial recording(SONY VGP-BPS21/S Battery), 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(SONY VGP-BPS21 Battery).

Disc phonograph

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(SONY VGP-BPS21B Battery), and they had the additional benefit of being louder (marginally) than cylinders, which by necessity, were single-sided(SONY VGP-BPS21A/B Battery). 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. Edison, who was the main producer of cylinders, created the Edison Disc Record in an attempt to regain his market(SONY VAIO PCG-5K1L battery). 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(SONY VAIO PCG-6W2L battery).

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(SONY VAIO PCG-7112L battery), 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) and available gearing ratio(SONY VAIO PCG-8Z1L battery)s. 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(SONY VAIO PCG-8Z2L battery).

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(SONY VAIO PCG-8Y2L battery); 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(SONY VAIO PCG-8Y1L battery).

The Vinyl microgroove was invented by a Hungarian engineer Peter Carl Goldmark. The vinyl microgroove record was introduced in the late 1940s, and the two main vinyl formats — the 7-inch single turning at 45 rpm and the 12-inch LP (long-playing) record turning at 33 1/3 rpm — had totally replaced the 78 rpm shellac (SONY VAIO PCG-7Z2L battery) (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 (SONY VAIO PCG-7Z1L battery) (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(SONY VAIO PCG-7133L battery).

Electrical recording

RCA-44, a classic ribbon microphone

Sound recording began as a mechanical process and remained so until the early 1920s (with the exception of the 1899 Telegraphone) when a string of groundbreaking inventions in the field of electronics revolutionised sound recording and the young recording industry(SONY VAIO PCG-7113L battery). These included sound transducers such as microphones and loudspeakers, and various electronic devices such as the mixing desk, designed for the amplification and modification of electrical sound signals(SONY VAIO PCG-6W3L battery).

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(SONY VAIO PCG-7111L battery). In 1906 Lee De Forest invented the "Audion" triode 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(SONY VAIO PCG-6W1L battery). The valve 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(SONY VAIO PCG-6V1L battery). Armstrong's inventions made higher fidelity electrical sound recording and reproduction a practical reality, facilitating the development of the electronic amplifier and many other devices; after 1925 these systems had become standard in the recording and radio industry(SONY VAIO PCG-6S3L battery).

While Armstrong published studies about the fundamental operation of the triode vacuum tube before World War I, inventors like Orlando R. Marsh and his Marsh Laboratories(SONY VAIO PCG-6S2L battery), 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(SONY VAIO PCG-5J2L battery). 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(SONY VAIO PCG-5L1L battery). 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(SONY VAIO PCG-5K2L battery).

Meanwhile, radio continued to develop. Armstrong's groundbreaking inventions (including FM radio) also made possible the broadcasting of long-range, high-quality radio transmissions of voice and music(SONY VAIO PCG-5J1L battery). 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 and receiver devices to this day(SONY VAIO PCG-5G3L battery).

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(SONY VAIO PCG-5G2L battery). 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(SONY VGP-BPS13B/S Battery), 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(SONY VGP-BPS13S Battery).

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, and the Columbia Phonograph Co. (SONY VGP-BPS13A/S Battery) (Edison was left out due to their decreasing market share and a stubborn Thomas Edison). 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(Sony VAIO VGN-FZ15G Battery). English Columbia, 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(Sony VAIO VGN-FZ15T Battery), 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(SONY VGP-BPS13/B Battery), 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(Dell N3010 Battery).

Other recording formats

In the 1920s, the early talkies featured 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(Dell INSPIRON 1464 battery). The introduction of talking movies, spearheaded by The Jazz Singer in 1927 (though it used a sound on disk technique, not a photoelectric one) (Dell INSPIRON 1520 battery), 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 took out ads in newspapers, protesting the replacement of real musicians with mechanical playing devices, especially in theatres(Dell INSPIRON E1505 battery).

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(SONY VGP-BPS13B/B Battery). 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(SONY VGP-BPS13 Battery). 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(SONY VAIO VGN-FZ31B Battery). 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(SONY VAIO VGN-FZ31M Battery).

The K1 Magnetophon 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 system, also generally credited to Lee De Forest(SONY VAIO VGN-FZ31J Battery). Although famous early "Talkies" like The Jazz Singer 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(SONY VAIO VGN-FZ31E Battery), 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(Sony Vaio VGN-FZ31S battery). 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(SONY VAIO VGN-FZ31z Battery).

Magnetic tape

Main article: magnetic tape sound recording

Other important inventions of this period were magnetic tape and the tape recorder (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(SONY VAIO VGN-FZ38M Battery). 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(SONY VAIO VGN-FZ210CE Battery). Tape recording was perfected just after the war by American audio engineer John T. Mullin with the help of Crosby Enterprises (Bing Crosby), whose pioneering recorders were based on captured German recorders, and the Ampex company produced the first commercially available tape recorders in the late 1940s(SONY VAIO VGN-FZ160 Battery).

A typical Compact Cassette

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(SONY VAIO VGN-FZ21 Battery), 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(SONY VAIO VGN-FZ410 Battery), American musician-inventor Les Paul had invented the first multitrack tape recorder, bringing about another technical revolution in the recording industry(SONY VAIO VGN-FZ21m Battery). 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(SONY VAIO VGN-FZ18m Battery).