AskDefine | Define microgroove

User Contributed Dictionary



  1. The long, spiral groove of a vinyl LP record

Extensive Definition

A gramophone record (also vinyl record, vinyl, phonograph record, or simply record) is an analogue sound storage medium consisting of a flat disc with an inscribed modulated spiral groove usually starting near the periphery and ending near the center of the disc. (Some commercial-use only records ran the groove from the center to the edge of the record.) Gramophone records were the primary medium used for commercial music reproduction for most of the 20th century. They replaced the phonograph cylinder as the most popular recording medium in the 1900s, and although they were supplanted in popularity in the late 1980s by digital media, they continue to be manufactured and sold as of 2008. Gramophone records remain the medium of choice for some audiophiles, and specialist areas such as electronic dance music and hip hop.

Type of record

The terms 33 1/3 rpm record ("33", also LP record or "LP"), EP, 16 2/3 rpm record ("16"), 45 rpm record ("45"), and 78 rpm record ("78") each refer to specific types of gramophone records. Except for the LP and EP (which are acronyms for Long Play, which referred to almost all 33 1/3 recordings (a few 33 1/3 rpm recordings contain only one short song per side), and Extended Play, which referred to 45 rpm recordings with twice the usual number of songs on each side, respectively), these type designations refer to their rotational speeds in revolutions per minute (rpm). LPs, 45s, and 16s are usually made of polyvinyl chloride (PVC), and hence may be referred to as vinyl records or simply vinyl.
Sizes of records in America and the UK are generally measured in inches, usually represented with a double prime symbol, e.g. a 7-inch or 7″ record. 45s are generally 7″ records. LPs were 10″ records at first, but are now usually 12″ records.


Early history

A device utilizing a vibrating pen to graphically represent sound on discs of paper, without the idea of playing it back in any manner, was built by Edouard-Leon Scott of France in 1857. The device, known as a phonautograph was built to examine the characteristics of sounds, but the inventor failed to appreciate that it actually recorded the sound. An early recording made in 1860 has recently been reproduced using computer technology.
In 1877, Thomas Edison developed the phonautograph into a machine, the phonograph, that was capable of replaying the recordings made. The recordings were made on tinfoil, and were initially intending to be used as a voice recording medium, typically for office dictation. This initial machine was developed further by Edward Guilliard, though his developments were subsequently incorporated into Edison's patent, something that he had to fight for the next 26 years.
This phonograph cylinder dominated the recorded sound market beginning in the 1880s. Lateral-cut disc records were invented by Emile Berliner in 1888 and were used exclusively in toys until 1894, when Berliner began marketing disc records under the Berliner Gramophone label. The Edison "Blue Amberol" cylinder was introduced in 1912, with a longer playing time of around 4 minutes (at 160 rpm) and a more resilient playing surface than its wax predecessor, but the format was doomed due to the difficulty of reproducing recordings. By November 1918 the patents for the manufacture of lateral-cut disc records expired, opening the field for countless companies to produce them, causing disc records to overtake cylinders in popularity. Production of Amberol cylinders ceased in the late 1920s. Disc records would dominate the market until they were supplanted by the Compact Disc, starting from the 1980s.

78 rpm disc developments

Early speeds

Early disc recordings were produced in a variety of speeds ranging from 60 rpm to 120 rpm, and a variety of sizes. At least one manufacturer, Philips, produced records that played at a constant linear velocity. As these were played from the inside to the outside, the rpm of the record reduced as reproduction progressed (as is also true of the modern Compact Disc).
As early as 1894, Emile Berliner's United States Gramophone Company was selling single-sided 7" discs with an advertised standard speed of "about 70 rpm."
One standard audio recording handbook describes speed regulators or "governors" as being part of a wave of improvement introduced rapidly after 1897. A picture of a hand-cranked 1898 Victrola shows a governor. It says that spring drives replaced hand drives and that "the speed regular was furnished with an indicator that showed the speed when the machine was running so that the records, on reproduction, could be revolved at exactly the same speed." It notes that "the literature does not disclose why 78 rpm was chosen for the phonograph industry, apparently this just happened to be the speed created by one of the early machines and, for no other reason continued to be used."
By 1925, the speed of the record became standardised on (nominally) 78 rpm. However, the standard was to differ between America and the rest of the world. The actual 78 speed in America was 78.26 rpm, being the speed of 3600 rpm synchronous motor (run from 60 Hz supply) reduced by 46:1 gearing. Throughout the rest of the world, 77.92 rpm was adopted being the speed of a 3000 rpm synchronous motor (run from 50 Hz supply reduced by 38.5:1 gearing. (See also below)

Acoustic recording

Early recordings were made entirely acoustically, the sound being collected by a horn and piped to a diaphragm which vibrated the cutting stylus. Sensitivity and frequency range were poor, and frequency response was very irregular, giving cylinder recordings an instantly recognizable tonal quality. A singer practically had to put his face in the recording horn. Cellos and double basses were completely unrecordable. Violins were barely recordable but instruments were modified with a horn built into the sound box to direct the sound into the recorder's horn.
When a jazz group recorded, drums were completely eliminated because their "boom" would dislodge the cutting stylus from the groove. The loudest instruments stood the farthest away from the collecting horn. Lillian Hardin Armstrong, a member of King Oliver's Creole Jazz Band that recorded at Gennett Records in 1923, remembered that at first Oliver and his young second trumpet, Louis Armstrong, stood next to each other and Oliver's horn couldn't be heard. "They put Louis about fifteen feet over in the corner, looking all sad." (See a photograph of Gennett's recording studio here.)

"Electrical" recording

During the 1920s, engineers, particularly at Western Electric, developed technology for capturing sound with microphones, amplifying it with vacuum tubes, and using the amplified signal to a drive an electromagnetic recording head. A wide frequency range could now be recorded, and there was no longer any limit on playback volume.
Although the technology used vacuum tubes and today would be described as "electronic," at the time it was referred to as "electrical." A 1926 Wanamaker's ad in The New York Times offers records "by the latest Victor process of electrical recording." It was recognized as a breakthrough; in 1930, a Times music critic stated
...the time has come for serious musical criticism to take account of performances of great music reproduced by means of the records. To claim that the records of succeeded in exact and complete reproduction of all details of symphonic or operatic performances... would be extravagant. [But] the article of today is so far in advance of the old machines has hardly to admit classification under the same name. Electrical recording and reproduction have combined to retain vitality and color in recitals by proxy.
Electrical recording preceded electrical home reproduction (much as digital recording preceded digital home reproduction), because of the initial high cost of the electronics. In 1925 the Victor company introduced the groundbreaking Victor Orthophonic Victrola, an acoustical record player that was specifically designed to play electrically recorded discs, as part of a line that also included electrically-reproducing "Electrolas." The acoustical Orthophonics ranged in price from $95 (about $1140 in year-2007 dollars) to $300, depending on cabinetry; by comparison, the cheapest Electrola cost $650 (about $7500 in year-2007 dollars).
The Orthophonic had an interior folded exponential horn, a sophisticated design informed by impedance-matching and transmission-line theory, and designed to provide a relatively flat frequency response. Its first public demonstration was front-page news in the New York Times, which reported that
The audience broke into applause... John Philip Sousa [said] "Gentleman[sic], that is a band. This is the first time I have ever heard music with any soul to it produced by a mechanical talking machine." ... The new instrument is a feat of mathematics and physics. It is not the result of innumerable experiments, but was worked out on paper in advance of being built in the laboratory.... The new machine has a range of from 100 to 5,000 frequencies[sic], or five and a half octaves.... The "phonograph tone" is eliminated by the new recording and reproducing process.
Gradually, electrical reproduction entered the home. The clockwork motor was replaced by an electric motor; the 'needle' and diaphragm (the 'sound box') was replaced with a 'pickup' using either a steel or sapphire stylus, and a transducer to convert the groove vibrations into an electrical signal. The exponential horn became an amplifier and loudspeaker.

78 rpm materials

Early disc records were made of various materials including hard rubber. From 1897 onwards, earlier materials were largely replaced by a rather brittle formula of 25% "shellac" (a material obtained from the secretion of a southeast Asian beetle), a filler of a cotton compound similar to manila paper, powdered slate, and a small amount of a wax lubricant. The mass production of shellac records began in 1898 in Hanover, Germany, and continued until the end of the 78-rpm format in the late 1950s. "Unbreakable" records, usually of celluloid (an early form of plastic) on a pasteboard base, were made from 1904 onwards, but they suffered from an exceptionally high level of surface noise. "Unbreakable" records could be bent, broken, or otherwise damaged; but not nearly as easily as the "breakable" records. Decca introduced vinyl "Deccalite" 78s after the Second World War, but other labels would restrict vinyl production to the newer 33 and 45 formats.

78 rpm disc size

In the 1890s the early recording formats of discs were usually seven inches (nominally 17.5 cm) in diameter. By 1910 the 10-inch (25.4 cm) record was by far the most popular standard, holding about three minutes of music or entertainment on a side. From 1903 onwards, 12-inch records (30.5 cm) were also commercially sold, mostly of classical music or operatic selections, with four to five minutes of music per side. However, other sizes did appear. An 8 inch disc with a 2 inch diameter label became popular, though short lived, in Europe. They cannot completely be played on much modern equipment because the tone arm cannot reach in far enough.

78-rpm recording time

The playing time of a phonograph record depended on the turntable speed and the groove spacing. At the beginning of the 20th century, the early discs played for 2 minutes, the same as early cylinder records. The 12 inch disc, introduced by Victor in 1903, increased the playing time to three and one-half minutes. Because a 10-inch 78-rpm record could hold about three minutes of sound per side and the 10-inch size was the standard size for popular music, almost all popular recordings were limited to around three minutes in length.
For example, when King Oliver's Creole Jazz Band, including Louis Armstrong on his first recordings, recorded 13 sides at Gennett Records in Richmond, Indiana, in 1923, one side was 2:09 and four sides were 2:52–2:59.
By 1938, when Milt Gabler started recording on January 17 for his new label, Commodore Records, to allow longer continuous performances, he recorded some 12" records. Eddie Condon explained: "Gabler realized that a jam session needs room for development." The first two 12" recordings didn't take advantage of the extra length: "Carnegie Grag" was 3:15; "Carnegie Jump", 2:41. But, at the second session, on April 30, the two 12" recordings were longer: "Embraceable You" was 4:05; "Serenade to a Shylock", 4:32.
Another way around the time limitation was to issue a selection on both sides of a single record. Vaudeville stars Ed Gallagher and Al Shean, known as Gallagher and Shean, recorded "Mr Gallagher and Mr Shean", written by Irving and Jack Kaufman, as two-sides of a 10" 78 in 1922 for Cameo. Click on "About this recording".
Eighteen years later, Commodore released a longer jazz recording in several parts: Eddie Condon and his Band's March 24, 1940, recording of "A Good Man Is Hard to Find" in four parts, issued on both sides of two 12" 78s. Each section is more than four minutes.
(The first multi-disc release was in 1903, when HMV in England made the first complete recording of an opera, Verdi's Ernani, on 40 single-sided discs. The discs' diameter is not indicated.)
This limitation on the length of both popular-music and jazz songs persisted from 1910 until the invention of the LP, in 1948.
In popular music, this time limitation of about 3:30 on a 10" 78-rpm record meant that singers usually did not release long songs on record. One exception is Frank Sinatra's recording of Richard Rodgers's and Oscar Hammerstein II's "Soliloquy", from Carousel, made on May 28, 1946. Because it ran 7:57, longer than both sides of a standard 78-rpm 10" record, it was released on Columbia's Masterwork label (the classical division) as two sides of a 12" record. (See date.)
In the 78 era, classical-music and spoken-word items generally were released on the longer 12" 78s, about 4–5 minutes per side. For example, on June 10 1924, four months after the February 12 premier of Rhapsody in Blue, George Gershwin recorded it with Paul Whiteman and His Orchestra. It was released on two sides of Victor 55225 and runs 8:59, so it had to have been a 12" 78. Look under the title

Record Albums

Such 78 rpm records were usually sold separately, in brown paper or cardboard sleeves that were sometimes plain and sometimes printed to show the producer or the retailer's name. Generally the sleeves had a circular cutout allowing the record label to be seen. Records could be laid on a shelf horizontially or stood upright on an edge, but because of their fragility, many broke in storage.
German record company Odeon pioneered the "album" in 1909 when it released the "Nutcracker Suite" by Tchaikovsky on 4 double-sided discs in a specially-designed package. # (It is not indicated what size the records are.) The practice of issuing albums does not seem to have been taken up by other record companies for many years.
Beginning in the 1920s, bound collections of empty sleeves with a cardboard or leather cover, similar to a photograph album, were sold as "record albums" that customers could use to store their records (the name "record album" was printed on some covers). These albums came in both 10" and 12" sizes. The covers of these bound books were wider and taller than the records inside, allowing the record album to be placed on a shelf upright, like a book, suspending the fragile records above the shelf and protecting them.
Starting in the 1930s, record companies began issuing collections of 78 rpm records by one performer or of one type of music in specially assembled albums. By the 1940s, these albums featured their own colorful paper covers and were in both 10-inch and 12-inch sizes, and could include either a collection of related popular songs, either by performer or style, or extended length classical music, including complete symphonies. The result is that when the LP came along and included multiple songs, the name "album" came along too.

New sizes and materials

Both the microgroove LP 33 1/3 rpm record and the 45 rpm single records are made from vinyl plastic that is flexible and unbreakable in normal use. However, the vinyl records are easier to scratch or gouge, and much more prone to warpage.
In 1930, RCA Victor launched the first commercially available vinyl long-playing record, marketed as "Program Transcription" discs. These revolutionary discs were designed for playback at 33 1/3 rpm and pressed on a 30 cm diameter flexible plastic disc. In Roland Gelatt's book The Fabulous Phonograph, the author notes that RCA Victor's early introduction of a long-play disc was a commercial failure for several reasons including the lack of affordable, reliable consumer playback equipment and consumer wariness during the Great Depression.
There were also a small batch of "longer playing" records issued in the very early 1930s. A handful were issued by Columbia on a special 18000-D series, and labels like Crown and Perfect also issued a few 10" records playing nearly 5 minutes long.
However, vinyl's lower surface noise level than shellac was not forgotten, nor was its durability. (Shellac records are very fragile.) In the late 30's, radio commercials and prerecorded radio programs being sent to disc jockeys started being stamped in vinyl, so they would not break in the mail. In the mid-1940s, special DJ copies of records started being made of vinyl also, for the same reason. These were all 78 rpm. During and after World War II when shellac supplies were extremely limited, some 78 rpm records were pressed in vinyl instead of shellac, particularly the six-minute 12-inch (30 cm) 78 rpm records produced by V-Disc for distribution to US troops in World War II. In the 40's, radio transcriptions, which were usually on 16 inch records, but sometimes 12 inch, were always made of vinyl, but cut at 33 1/3 rpm. Shorter transcriptions were often cut at 78 rpm.
Beginning in 1939, Columbia Records continued development of this technology. Dr. Peter Goldmark and his staff undertook exhaustive efforts to address problems of recording and playing back narrow grooves and developing an inexpensive, reliable consumer playback system. In 1948, the 12-inch (30 cm) Long Play (LP) 33 1/3 rpm microgroove record album was introduced by the Columbia Record Company at a dramatic New York press conference on June 21 1948. In February 1949, RCA Victor released the first 45 rpm single, 7 inches in diameter, with a large center hole to accommodate an automatic play mechanism on the changer, so a stack of singles would drop down one record at a time automatically after each play. Early 45 rpm records were made from either vinyl or polystyrene. They had a playing time of 8 minutes.
On a small number of early phonograph systems and radio transcription discs, as well as some entire albums, such as Goodbye Blue and White by Less Than Jake, the direction of the groove is reversed, beginning near the centre of the disc and leading to the outside. A small number of records (such as Jeff Mills' Apollo EP or the Hidden In Plainsight EP from Detroit's Underground Resistance) were manufactured with multiple separate grooves to differentiate the tracks (usually called 'NSC-X2'). X2 was pioneered by Ron Murphy and Heath Brunner from Sound Enterprises (formerly National Sound Corporation), a record mastering company in Detroit.


The earliest rotation speeds varied widely. Most records made in 1900–1925 were recorded at 74–82 revolutions per minute (rpm). However a few unusual systems were deployed. The Dutch Philips company introduced records whose rotational speed varied such that the reproducing "needle" ran at a constant linear velocity (CLV) in the groove. These records also, unusually, played from the inside to the outside. Both of these features were to be emulated by the modern day Compact Disc. The London Science Museum displays a Philips CLV record marked as "Speed D".
In 1925, 78.26 rpm was chosen as the standard because of the introduction of the electrically powered synchronous turntable motor. This motor ran at 3600 rpm with a 46:1 gear ratio which produced 78.26 rpm. In parts of the world that used 50 Hz current, the standard was 77.92 rpm (3000 rpm with a 38.5:1 ratio), which was also the speed at which a strobe disc with 77 lines would "stand still" in 50 Hz light (92 lines for 60Hz). Thus these records became known as 78s (or "seventy-eights"). This term did not come into use until after World War II when a need developed to distinguish the 78 from other newer disc record formats, an example of a retronym. Earlier they were just called records, or when there was a need to distinguish them from cylinders, disc records. Standard records was also used, although the same term had also been used earlier for two-minute cylinders.
After World War II, two new competing formats came on to the market and gradually replaced the standard "78": the 33 1/3 rpm (often just referred to as the 33 rpm), and the 45 rpm (see above). The 33 1/3 rpm LP (for "long play") format was developed by Columbia Records and marketed in 1948. RCA Victor developed the 45 rpm format and marketed it in 1949, in response to Columbia. Both types of new disc used narrower grooves, intended to be played with a smaller stylus—typically 0.001 inches (25 µm) wide, compared to 0.003 inches (76 µm) for a 78—so the new records were sometimes called Microgroove. In the mid-1950s all record companies agreed to a common recording standard called RIAA equalization. Prior to the establishment of the standard each company used its own preferred standard, requiring discriminating listeners to use preamplifiers with multiple selectable equalization curves.
A number of recordings were pressed at 16 2/3 rpm (usually a 7-inch disc, visually identical to a 45 rpm single), but these were mostly used for radio transcription discs or narrated publications for the blind and visually impaired, and were never widely commercially available, although it was common to see turntables with a 16 rpm speed setting produced as late as the 1970s.
The older 78 format continued to be mass produced alongside the newer formats into the 1950s, and in a few countries, such as India, into the 1960s. For example, Columbia records last reissue of Frank Sinatra songs on 78 rpm records was an album called "Young at Heart", issued November 1 1954. As late as the 1970s, some children's records were released at the 78 rpm speed.
The commercial rivalry between RCA Victor and Columbia Records led to RCA Victor's introduction of what it had intended to be a competing vinyl format, the 7-inch (175 mm) 45-rpm disc. For a two-year period from 1948 to 1950, record companies and consumers faced uncertainty over which of these formats would ultimately prevail in what was known as the "War of the Speeds". (See also format war.) In 1949 Capitol and Decca adopted the new LP format and RCA gave in and issued its first LP in January 1950. But the 45 rpm size was gaining in popularity, too, and Columbia issued its first 45s in February 1951. By 1954, 200 million 45s had been sold.
Eventually the 12-inch (300 mm) 33 1/3 rpm LP prevailed as the predominant format for musical albums and the 10" LP were no longer issued. The last Columbia records reissue of any Frank Sinatra songs on a 10" LP record was an album called "Hall of Fame", CL 2600, issued October 26 1956, containing six songs, one each by Tony Bennett, Rosemary Clooney, Johnny Ray, Frank Sinatra, Doris Day, and Frankie Laine. The 7-inch (175 mm) 45-rpm disc or "single" established a significant niche for shorter duration discs, typically containing one song on each side. The 45 rpm discs typically emulated the playing time of the former 78 rpm discs, while the 12" LP discs provided up to one half hour of time per side. The amount of music per LP varied from label to label and possibly performer to performer. Frank Sinatra's "A Swinging Affair", a mono album, contained 15 songs and ran 50 minutes. Other albums by other performers could run as little as 30 or 35 minutes. After the introducion of stereo recording, record times dropped because, presumably, the early stereo groove was wider than the mono groove.
The 45 rpm discs also came in a variety known as Extended play (EP) which achieved up to 10–15 minutes play at the expense of attenuating (and possibly compressing) the sound to reduce the width required by the groove. EP discs were generally used to reissue LP albums on the smaller format for those people who had only 45 rpm players. LP albums could be purchased 1 EP at a time, with four songs per EP, or in a boxed set with 3 EPs or 12 songs. The large center hole on 45s allows for easier handling by jukebox mechanisms. EPs were generally discontinued by the late 1950s as three and four speed record players replaced the individual 45 players. One indication of the decline of the 45 rpm EP is that the last Columbia records reissue of Frank Sinatra songs on 45 rpm EP records, called "Frank Sinatra",(Columbia B-2641) was issued December 7 1959.
In the late 1940s and early 1950s, 45 rpm–only players that lacked speakers and plugged into a jack on the back of a radio were widely available. Eventually, they were replaced by the three–speed record player.
From the mid-1950s through the 1960s, in the U.S. the common home "record player" or "stereo" (after the introduction of stereo recording) would typically have had these features: a three- or four-speed player (78, 45, 33 1/3, and sometimes 16 2/3 rpm); with changer, a tall spindle that would hold several records and automatically drop a new record on top of the previous one when it had finished playing, a combination cartridge with both 78 and microgroove styluses and a way to flip between the two; and some kind of adapter for playing the 45s with their larger center hole. The adapter could be a small solid circle that fit onto the bottom of the spindle (meaning only one 45 could be played at a time) or a larger adaptor that fit over the entire spindle, permitting a stack of 45s to be played.
RCA 45s were also adapted to the smaller spindle of an LP player with a plastic snap-in insert known as a "spider". These inserts, commissioned by RCA president David Sarnoff and invented by Thomas Hutchison, were prevalent starting in the 1960s, selling in the tens of millions per year during the 45's heyday.
Deliberately playing or recording records at the wrong speed was a common amusement. Playing at a higher speed gave an antic quirkiness to voices whereas playing at a slower speed changed music and voice to an ominous, growling tone. This effect was used in 1966 by Cork Marcheschi of California group the Ethix (and later of Fifty Foot Hose), who issued an experimental single, "Bad Trip", which could be played at any speed. Canadian musician Nash the Slash also took advantage of this speed/tonal effect with his 1981 12-inch disc Decomposing, which featured four instrumental tracks that were engineered to play at any speed (with the playing times listed for 33 1/3, 45 and 78 rpm playback). Music from a 33 1/3 rpm LP of the animated musical group Alvin and the Chipmunks can be played at 16 rpm to reveal how male voices singing very slowly are used to produce the high pitched rodents' voices apparently singing the song at normal speed.

Sound enhancements

As the LP became established as the dominant size for longer recordings, several developments were made to enhance the sound.

High fidelity

The first of these was the attempt to develop high fidelity, or hi-fi, sound. People who were concerned with hearing all the quality sound now embedded in the new LPs began to buy separate turntables, amplifiers, and speakers and woofers to get the best sound possible. Stan Freberg satirized these fans in his 1956 radio show with a skit about a man who turned his whole house into a speaker.

Stereo sound

In 1958 the first stereo two-channel records were issued—by Audio Fidelity in the USA and Pye in Britain, using the Westrex "45/45" single-groove system. While the stylus moves horizontally when reproducing a monophonic disk recording, on stereo records the stylus moves vertically as well as horizontally.
One could envision a system in which the left channel was recorded laterally, as on a monophonic recording, with the right channel information recorded with a "hill-and-dale" vertical motion; such systems were proposed but not adopted, due to their incompatibility with existing phono pickup designs (see below). In the Westrex system, each channel drives the cutting head at a 45 degree angle to the vertical. During playback the combined signal is sensed by a left channel coil mounted diagonally opposite the inner side of the groove, and a right channel coil mounted diagonally opposite the outer side of the groove.
It is helpful to think of the combined stylus motion in terms of the vector sum and difference of the two stereo channels. Effectively, all horizontal stylus motion conveys the L+R sum signal, and vertical stylus motion carries the L-R difference signal. The advantages of the 45/45 system are:
  • greater compatibility with monophonic recording and playback systems. A monophonic cartridge will reproduce an equal blend of the left and right channels instead of reproducing only one channel. (However many monophonic cartridges would damage a stereo groove, leading to the common recommendation to never use a mono cartridge on a stereo record.) Conversely, a stereo cartridge reproduces the lateral grooves of monophonic recording equally through both channels, rather than one channel.
  • a more balanced sound, because the two channels have equal fidelity (rather than providing one higher-fidelity laterally recorded channel and one lower-fidelity vertically recorded channel);
  • higher fidelity in general, because the "difference" signal is usually of low power and thus less affected by the intrinsic distortion of hill-and-dale recording.
This system was invented by Alan Blumlein of EMI in 1931 and patented the same year. EMI cut the first stereo test discs using the system in 1933. It was not used commercially until a quarter of a century later.
Stereo sound provides a more natural listening experience where the spatial location of the source of a sound is, at least in part, reproduced.
Under the direction of C. Robert Fine, Mercury Records initiated a minimalist single microphone monaural recording technique in 1951. The first record, Kubelik/Chicago's performance of "Pictures at an Exhibition" was described as "being in the living presence of the orchestra" by The New York Times music critic. The series of records was then named “Mercury Living Presence”. In 1955 Mercury began three-channel stereo recordings, still based on the principle of the single microphone. The center (single) microphone was of paramount importance, with the two side mics adding depth and space. Record masters were cut directly from a three-track to two-track mixdown console, with all editing of the master tapes done on the original three-tracks. In 1961 Mercury enhanced this technique with three-microphone stereo recordings using 35-mm magnetic film instead of half-inch tape for recording. The greater thickness and width of 35 mm magnetic film prevented tape layer print-through and pre-echo and gained extended frequency range and transient response. The Mercury Living Presence recordings were remastered to CD in the 1990s by the original producer, using the same method of 3-to-2 mix directly to the master recorder.
The development of quadraphonic records was announced in 1971. These recorded four separate sound signals. This was achieved on the two stereo channels by electronic matrixing, where the additional channels were combined into the main signal. When the records were played, phase-detection circuits in the amplifiers were able to decode the signals into four separate channels. There were two main systems of matrixed quadraphonic records produced, confusingly named SQ (by CBS) and QS (by Sansui). They proved commercially unsuccessful, but were an important precursor to later "surround sound" systems, as seen in SACD and home cinema today. A different format, CD-4 (not to be confused with compact disc), by RCA, encoded rear channel information on an ultrasonic carrier, which required a special wideband cartridge to capture it on carefully-calibrated pickup arm/turntable combinations. Typically the high frequency information inscribed onto these LPs wore off after only a few playings, and CD-4 was even less successful than the two matrixed formats.
In the late 1970s and 1980s, a method to improve the dynamic range of mass produced records involved highly advanced disc cutting equipment. These techniques, marketed as the CBS DisComputer and Teldec Direct Metal Mastering, were used to reduce inner-groove distortion. RCA Victor introduced another system to boost dynamic range and achieve a groove with less surface noise under the commercial name of Dynagroove. Two main elements were combined: another disk material with less surface noise in the groove and dynamic expansion for masking background noise. Sometimes this was called "diaphragming" the source material and not favoured by some music lovers for its unnatural side effects. Both elements were reflected in the brandname of Dynagroove, described elsewhere in more detail. Furthermore it used advanced forward looking steering on track distance with respect to volume of sound and position on the disk. Tracks were close to each other with lower volumes and farther away with loud passages. Also the higher track density at lower volumes enabled disk recordings to end farther away from the inner circle than usual, helping to reduce endtrack distorsion even further.
Also in the late 1970s, "direct-to-disc" records were produced, aimed at an audiophile niche market. These completely bypassed the use of magnetic tape in favor of a "purist" transcription directly to the master lacquer disc. Also during this period, "half-speed mastered" and "original master" records were released, using expensive state-of-the-art technology. A further late 1970s development was the Disco Eye-Cued(TM) system used mainly on Motown 12-inch singles released between 1978 and 1980. The introduction, drum-breaks or choruses of a track were indicated by widely separated grooves, giving a visual clue to DJs mixing the records. The appearance of these records is similar to an LP, but they only contain one track each side.
The early 1980s saw the introduction of "dbx-encoded" records, again for the audiophile niche market. These were completely incompatible with standard record playback preamplifiers, relying on the dbx compandor encoding/decoding scheme to greatly increase dynamic range (dbx encoded disks were recorded with the dynamic range compressed by a factor of two in dB: quiet sounds were meant to be played back at low gain and loud sounds were meant to be played back at high gain, via automatic gain control in the playback equipment; this reduced the effect of surface noise on quiet passages). A similar and very short lived scheme involved using the CBS-developed "CX" noise reduction encoding/decoding scheme.

Play by laser with no wear off

ELPJ, a Japanese-based company, has developed a player that uses a laser instead of a stylus to read vinyl discs. In theory the laser turntable eliminates the possibility of scratches and attendant degradation of the sound, but its expense limits use primarily to digital archiving of analog records. Various other laser-based turntables were tried during the 1990s, but while a laser reads the groove very accurately, since it does not touch the record, the dust that vinyl naturally attracts due to static charge is not cleaned from the groove, worsening sound quality in casual use compared to conventional stylus playback.


|- | 7 in. (17.5 cm) || 45 rpm || Extended play (EP) |- | 7 in. (17.5 cm) || 33 1/3 rpm || Often used for children's records in the 1960s and 1970s. |}
Note: Before the early 1950s, the 33 1/3 rpm LP was most commonly found in a 10-inch (25 cm) format. The 10-inch format disappeared from United States stores around 1950, but remained a common format in some markets until the mid-1960s.

Less common formats


The normal commercial disc is engraved with two sound bearing concentric spiral grooves, one on each side of the disc, running from the outside edge towards the centre. Since the late 1910s, both sides of the record have been used to carry the grooves. Occasionally, records were issued in the 1920s with a recording on only one side. The recording is played back by rotating the disc clockwise at a constant rotational speed with a stylus (needle) placed in the groove, converting the vibrations of the stylus into an electric signal (see magnetic cartridge), and sending this signal through an amplifier to loudspeakers.
The majority of non–78 rpm records are pressed on black vinyl. The colouring material used to blacken the transparent PVC plastic mix is carbon black, the generic name for the finely divided carbon particles produced by the incomplete burning of a mineral oil based hydrocarbon. Carbon black increases the strength of the disc and renders it opaque. Polystyrene is often used for 7-inch records
Some records are pressed on coloured vinyl or with paper pictures embedded in them ("picture discs"). (There were also picture discs during the 78 era.) Fantasy Records pressed LPs on colored vinal in the 1950s. These discs can become collectors' items in some cases. Certain 45-rpm RCA or RCA Victor "Red Seal" records used red translucent vinyl for extra "Red Seal" effect. During the 1980s there was a trend for releasing singles on coloured vinyl—sometimes with large inserts that could be used as posters. This trend has been revived recently and has succeeded in keeping 7-inch singles a viable format.
Vinyl record standards for the United States follow the guidelines of the Recording Industry Association of America (RIAA). The inch dimensions are nominal, not precise diameters. The actual dimension of a 12-inch record is 302 mm (11.89 in), for a 10-inch it is 250 mm (9.84 in), and for a 7-inch it is 175 mm (6.89 in).
Records made in other countries are standardized by different organizations, but are very similar in size. The record diameters are typically 300 mm, 250 mm and 175 mm.
There is an area about 6 mm (0.25 in) wide at the outer edge of the disk, called the lead-in where the groove is widely spaced and silent. This section allows the stylus to be dropped at the start of the record groove, without damaging the recorded section of the groove.
Between each track on the recorded section of an LP record, there is usually a short gap of around 1 mm (0.04 in) where the groove is widely spaced. This space is clearly visible, making it easy to find a particular track.
Towards the label centre, at the end of the groove, there is another wide-pitched section known as the lead-out. At the very end of this section, the groove joins itself to form a complete circle, called the lock groove; when the stylus reaches this point, it circles repeatedly until lifted from the record. On some recordings (for example Sgt. Pepper's Lonely Hearts Club Band by The Beatles), the sound continues on the lock groove, which gives a strange repeating effect. Automatic turntables rely on the position or angular velocity of the arm, as it reaches these more widely spaced grooves, to trigger a mechanism that raises the arm and moves it out of the way of the record. Vinyl records do not break easily, but the soft material is easily scratched. Vinyl readily acquires a static charge, attracting dust that is difficult to remove completely. Dust and scratches cause audio clicks and pops. In extreme cases, they can cause the needle to skip over a series of grooves, or worse yet, cause the needle to skip backwards, creating a "locked groove" that repeats over and over. Locked grooves were not uncommon and were even heard occasionally in broadcasts.
Vinyl records can be warped by heat, improper storage, or manufacturing defects such as excessively tight plastic shrinkwrap on the album cover. A small degree of warp was common, and allowing for it was part of the art of turntable and tonearm design. "Wow" (once-per-revolution pitch variation) could result from warp, or from a spindle hole that was not precisely centered.
There is controversy about the relative quality of CD sound and LP sound when the latter is heard under the very best conditions (see Analog vs. Digital sound argument).
A further limitation of the record is that with a constant rotational speed, the quality of the sound may differ across the width of the record because the inner groove modulations are more compressed than those of the outer tracks. The result is that inner tracks have distortion that can be noticeable at higher recording levels.
7-inch singles were typically poorer quality for a variety of the reasons mentioned above, and in the 1970s the 12-inch single (commonly referred to as a "donut"), played at 45 rpm, became popular for DJ use and for fans and collectors.
Another problem arises because of the geometry of the tonearm. Master recordings are cut on a recording lathe, where a sapphire stylus moves radially across the blank, suspended on a straight track and driven by a lead screw. Most turntables use a pivoting tonearm, introducing side forces and pitch and azimuth errors, and thus distortion in the playback signal. Various mechanisms were devised in attempts to compensate, with varying degrees of success. See more at phonograph.

Frequency response and noise

In 1925, electric recording extended the recorded frequency range from acoustic recording (168–2000 Hz) by 2½ octaves to 100–5000 Hz. Even so, these early electronically recorded records used the exponential-horn phonograph (see Orthophonic Victrola) for reproduction.
The frequency response of vinyl records may be degraded by frequent playback if the cartridge is set to track too heavily, or the stylus is not compliant enough to trace the high frequency grooves accurately, or the cartridge/tonearm is not properly aligned. The best cartridges and styli have response up to 76 kHz. The RIAA has suggested the following acceptable losses: down to 20 kHz after one play, 18 kHz after three plays, 17 kHz after five, 16 kHz after eight, 14 kHz after fifteen, 13 kHz after twenty five, 10 kHz after thirty five, and 8 kHz after eighty plays. While this degradation is possible if the record is played on improperly set up equipment, many collectors of LPs report excellent sound quality on LPs played many more times when using care and high quality equipment. This rapid sound degradation is not usually typical on modern Hi-Fi equipment with a properly balanced tonearm and well balanced low mas stylus. The RIAA standard represents only the minimum acceptable losses. Most properly setup Hi-Fi systems can provide much higher record life and sound quality.
CD-4 LPs contain two sub-carriers, one in the left groove wall and one in the right groove wall. These sub-carriers use special FM-PM-SSBFM (Frequency Modulation-Phase Modulation-Single Sideband Frequency Modulation) and have signal frequencies that extend to 45 kHz. Many record collectors report that the CD-4 sub-carriers are still playable, even though the records have been played extensively and are in excess of 30 years old. It should be noted that these records could be played with any type stylus as long as the pickup cartridge had CD-4 frequency response. The recommended Stylus for CD-4 as well as regular stereo records was a line contact or Shibata type.
Gramophone sound suffers from rumble, low-frequency (below about 30 Hz) mechanical noise generated by the motor bearings and picked up by the stylus. Equipment of modest quality is relatively unaffected by these issues, as the amplifier and speaker will not reproduce such low frequencies, but high-fidelity turntable assemblies need careful design to minimize audible rumble.
Room vibrations will also be picked up if the pedestal—turntable—pickup arm—stylus system is not well damped.
Tonearm skating forces and other perturbations are also picked up by the stylus. This is a form of frequency multiplexing as the "control signal" (restoring force) used to keep the stylus in the groove is carried by the same mechanism as the sound itself. Subsonic frequencies below about 20 Hz in the audio signal are dominated by tracking effects, which is one form of unwanted rumble ("tracking noise") and merges with audible frequencies in the deep bass range up to about 100 Hz. High fidelity sound equipment can reproduce tracking noise and rumble. During a quiet passage, woofer speaker cones can sometimes be seen to vibrate with the subsonic tracking of the stylus, at frequencies as low as about 0.5 Hz (the frequency at which a 33 1/3 rpm record turns on the turntable). Another reason for very low frequency material can be a warped disk: its undulations produce frequencies of only a few hertz and presentday amplifiers have large power bandwidths. For this reason, many stereo receivers contained a switchable subsonic filer. Some subsonic content is directly out of phase in each channel. If played back on a mono subwoofer system, the noise will cancel, significantly reducing the amount of rumble that is reproduced.
At high audible frequencies, hiss is generated as the stylus rubs against the vinyl, and from dirt and dust on the vinyl. Noise can be reduced somewhat by cleaning the record prior to playback.
Another method, introduced by the Lenco company is playing the disk "wet". Using a special dispenser the groove is wetted ahead of the stylus passing by and dries up afterwards. This certainly reduces hiss, but when it became clear that any disk once played wet, should forever be played this way because of residue left behind, people did not change over in great numbers. With normal cleaning this problem does not occur (this also seems to remove Lenco residue if present).


Due to recording mastering and manufacturing limitations, both high and low frequencies were removed from the first recorded signals by various formulae. With low frequencies, the stylus must swing a long way from side to side, requiring the groove to be wide, taking up more space and limiting the playing time of the record. At high frequencies noise is significant. These problems can be compensated for by using equalization to an agreed standard. This simply means reducing the amplitude at low-frequencies, thus reducing the groove width required, and increasing the amplitude at high frequencies. The playback equipment boosts bass and cuts treble in a complementary way. The result should be that the sound is perceived to be without change, thus more music will fit the record, and noise is reduced.
The agreed standard has been RIAA equalization since 1952, implemented in 1955. Prior to that, especially from 1940, some 100 formulae were used by the record manufacturers.
In 1926 it was disclosed by Joseph P. Maxwell and Henry C. Harrison from Bell Telephone Laboratories that the recording pattern of the Western Electric (W. E.) "rubber line" magnetic disc cutter had a constant velocity characteristic. This meant that as frequency increased in the treble, recording amplitude decreased. Conversely, in the bass as frequency decreased, recording amplitude increased. Therefore, it was necessary to attenuate the bass frequencies below about 250 Hz, the bass turnover point, in the amplified microphone signal fed to the recording head. Otherwise, bass modulation became excessive and overcutting took place into the next record groove. When played back electrically with a magnetic pickup having a smooth response in the bass region, a complementary boost in amplitude at the bass turnover point was necessary. G. H. Miller in 1934 reported that when complementary boost at the turnover point was used in radio broadcasts of records, the reproduction was more realistic and many of the musical instruments stood out in their true form.
West in 1930 and later P. G. H. Voight (1940) showed that the early Wente-style condenser microphones contributed to a 4 to 6 dB midrange brilliance or pre-emphasis in the recording chain. This meant that the electrical recording characteristics of W. E. licensees such as Columbia Records and Victor Talking Machine Company in the 1925 era had a higher amplitude in the midrange region. Brilliance such as this compensated for dullness in many early magnetic pickups having drooping midrange and treble response. As a result, this practice was the empirical beginning of using pre-emphasis above 1,000 Hz in 78 rpm and 33 1/3 rpm records.
Over the years a variety of record equalization practices emerged and there was no industry standard. For example, in Europe recordings for years required playback with a bass turnover setting of 250–300 Hz and a treble rolloff at 10,000 Hz ranging from 0 to −5 dB or more. In the United States there were more varied practices and a tendency to use higher bass turnover frequencies such as 500 Hz as well as a greater treble rolloff like −8.5 dB and even more to record generally higher modulation levels on the record. Evidence from the early technical literature concerning electrical recording suggests that it wasn't until the 1942–1949 period that there were serious efforts to standardize recording characteristics within an industry. Heretofore, electrical recording technology from company to company was considered a proprietary art all the way back to the 1925 W. E. licensed method used by Columbia and Victor. For example, what Brunswick-Balke-Collender (Brunswick Corporation) did was different from the practices of Victor.
Broadcasters were faced with having to adapt daily to the varied recording characteristics of many sources: various makers of "home recordings" readily available to the public, European recordings, lateral cut transcriptions, and vertical cut transcriptions. Efforts were started in 1942 to standardize within the National Association of Broadcasters (NAB), later known as the National Association of Radio and Television Broadcasters (NARTB). The NAB, among other items, issued recording standards in 1949 for laterally and vertically cut records, principally transcriptions. A number of 78 rpm record producers as well as early LP makers also cut their records to the NAB/NARTB lateral standard.
The lateral cut NAB curve was remarkably similar to the NBC Orthacoustic curve which evolved from practices within the National Broadcasting Company since the mid-1930s. Empirically, and not by any formula, it was learned that the bass end of the audio spectrum below 100 Hz could be boosted somewhat to override system hum and turntable rumble noises. Likewise at the treble end beginning at 1,000 Hz, if audio frequencies were boosted by 16 dB at 10,000 Hz the delicate sibilant sounds of speech and high overtones of musical instruments could survive the noise level of cellulose acetate, lacquer/aluminum, and vinyl disc media. When the record was played back using a complementary inverse curve, signal to noise ratio was improved and the programming sounded more life-like.
When the Columbia LP was released in June 1948, the developers subsequently published technical information about the 33 1/3 rpm microgroove long playing record. Columbia disclosed a recording characteristic showing that it was like the NAB curve in the treble, but had more bass boost or pre-emphasis below 200 Hz. The authors disclosed electrical network characteristics for the Columbia LP curve. This was the first such curve based on formulae.
In 1951 at the beginning of the post-World War II high fidelity (hi-fi) popularity, the Audio Engineering Society (AES) developed a standard playback curve. This was intended for use by hi-fi amplifier manufacturers. If records were engineered to sound good on hi-fi amplifiers using the AES curve, this would be a worthy goal towards standardization. This curve was defined by the time constants of audio filters and had a bass turnover of 400 Hz and a 10,000 Hz rolloff of −12 dB.
RCA Victor and Columbia were in a "market war" concerning which recorded format was going to win: the Columbia LP versus the RCA Victor 45 rpm disc (released in February 1949). Besides also being a battle of disc size and record speed, there was a technical difference in the recording characteristics. RCA Victor was using "New Orthophonic" whereas Columbia was using the LP curve.
Ultimately the New Orthophonic curve was disclosed in a publication by R. C. Moyer of RCA Victor in 1953. He traced RCA Victor characteristics back to the W. E. "rubber line" recorder in 1925 up to the early 1950s laying claim to long-held recording practices and reasons for major changes in the intervening years. The RCA Victor New Orthophonic curve was within the tolerances for the NAB/NARTB, Columbia LP, and AES curves. It eventually became the technical predecessor to the RIAA curve and superseded all other curves. By the time of the stereo LP in 1958, the RIAA curve, identical to the RCA Victor New Orthophonic curve, became standard throughout the national and international record markets.

Sound fidelity

Overall sound fidelity of records produced acoustically using horns instead of microphones had a distant, hollow tone quality. Some voices and instruments recorded better than others; Enrico Caruso, famous tenor, was one popular recording artist of the acoustic era that was well matched to the recording horn. It has been asked, "Did Caruso make the phonograph or did the phonograph make Caruso?"
Delicate sounds and fine overtones were mostly lost because it took a lot of sound energy to vibrate the recording horn diaphragm and cutting mechanism. There were acoustic limitations due to mechanical resonances in both the recording and playback system. Some pictures of acoustic recording sessions show horns wrapped with tape to help mute these resonances. Even an acoustic recording played back electrically on modern equipment sounds like it was recorded through a horn, not withstanding a 50% reduction in distortion because of the modern playback. Towards the end of the acoustic era, there were many fine examples of recordings made with horns.
Electric recording which developed during the time that early radio was becoming popular (1925) benefited from the microphones and amplifiers used in radio studios. The early electric recordings were reminiscent tonally of acoustic recordings except there was more recorded bass and treble as well as delicate sounds and overtones cut on the records. This was in spite of some carbon microphones used which had resonances that colored the recorded tone. The double button carbon microphone with stretched diaphragm was a marked improvement. Alternatively, the Wente style condenser microphone used with the Western Electric (W. E.) licensed recording method had a brilliant midrange and was prone to overloading from sibilants in speech, but it was generally better at picking up sounds more accurately than carbon microphones were.
It was not unusual, however, for electric recordings to be played back on acoustic phonographs. The Victor Orthophonic phonograph was a prime example where such playback was expected. In the Orthophonic, which benefited from telephone research, the mechanical pickup head was redesigned with lower resonance than the traditional mica type. Also, a folded horn with an exponential taper was constructed inside the cabinet to provide better impedance matching to the air. As a result, playback of an Orthophonic record sounded like it was coming from a radio.
Eventually, when it was more common for electric recordings to be played back electrically in the 1930s and '40s, the overall tone was much like listening to a radio of the era. Magnetic pickups became more common and were better designed as time went on to dampen spurious resonances. Crystal pickups were also introduced as lower cost alternatives. The dynamic or moving coil microphone was introduced around 1930 and the velocity or ribbon microphone in 1932. Both of these high quality microphones became widespread in motion picture, radio, recording, and public address applications.
Over time, fidelity, dynamic and noise levels improved to the point that it was harder to tell the difference between a live performance in the studio and the recorded version. This was especially true after the invention of the variable reluctance magnetic pickup cartridge by General Electric in the 1940s when high quality cuts were played on well-designed audio systems. The Capehart radio/phonographs of the era with large diameter electrodynamic loudspeakers, though not ideal, demonstrated this quite well with "home recordings" readily available in the music stores for the public to buy.
There were important quality advances in recordings specifically made for radio broadcast. In the early 1930s Bell Telephone Laboratories and Western Electric announced the total reinvention of disc recording: the Western Electric Wide Range System, "The New Voice of Action." The intent of the new W. E. system was to improve the overall quality of disc recording and playback. The recording speed was 33 1/3 rpm, originally used in the Western Electric/ERPI movie audio disc system implemented in the early Warner Brothers' Vitaphone "talkies" of 1927.
The newly invented W. E. moving coil or dynamic microphone was part of the Wide Range System. It had a flatter audio response than the old style Wente condenser type and didn't require electronics installed in the microphone housing. Signals fed to the cutting head were pre-emphasized in the treble region to help override noise in playback. Groove cuts in the vertical plane were employed rather than the usual lateral cuts. The chief advantage claimed was more grooves per inch which could be crowded together resulting in longer playback time. Additionally, the problem of inner groove distortion which plagued lateral cuts could be avoided with the vertical cut system. Wax masters were made by flowing heated wax over a hot metal disc thus avoiding the microscopic irregularities of cast blocks of wax and the necessity of planing and polishing.
Vinyl pressings were made with stampers from master cuts that were electroplated in vacuo by means of gold sputtering. Audio response was claimed out to 8,000 Hz, later 13,000 Hz, using light weight pickups employing jeweled styli. Amplifiers and cutters both using negative feedback were employed thereby improving the range of frequencies cut and lowering distortion levels. Radio transcription producers such as World Broadcasting System and Associated Music Publishers (AMP) were the dominant licensees of the W. E. wide range system and towards the end of the 1930s were responsible for two thirds of the total radio transcription business. A quantum level of improvement had been achieved, and when these recordings are found today in good condition, it is amazing to hear what high fidelity sound was like in that era. Playback of these recordings works well using a bass turnover of 300 Hz and a 10,000 Hz rolloff of −8.5 dB.
Developmentally, much of the technology of the long playing record, successfully released by Columbia in 1948, came from wide range radio transcription practices. The use of vinyl pressings, increased length of programming, and general improvement in audio quality over 78 rpm records were the major selling points.
The complete technical disclosure of the Columbia LP by Peter C. Goldmark, Rene' Snepvangers and William S. Bachman in 1949 made it possible for a great variety of record companies to get into the business of making long playing records. The business grew like "wild fire" as did the widespread interest in high fidelity sound and the do-it-yourself market for pickups, turntables, amplifier kits, loudspeaker enclosure plans, and AM/FM radio tuners. The LP record for longer works, 45 rpm for pop songs, and FM radio became high fidelity program sources in demand. Radio listeners heard recordings broadcasted and this in turn generated more record sales. The industry flourished.

Evolutionary steps

Technology used in making recordings also developed and prospered. Basically there were ten major evolutionary steps that perfected LP production and quality during a period of approximately forty years.
  1. Electrical transcriptions and 78s were first used as sources to master LP lacquer/aluminum cuts in 1948. This was before magnetic tape was commonly employed for mastering. Variable pitch groove spacing helped enable greater recorded dynamic levels. The heated stylus improved the cutting of high frequencies. Gold sputtering in vacuo became increasingly used to make high quality matrices from the cuts to stamp vinyl records.
  2. Decca in England employed high quality wide range microphones (condensers) for the Full Frequency Range Recording (FFRR) system ca. 1949. Wax mastering was employed to produce Decca/London LPs. This created quite a bit of interest in the United States and raised overall quality expectations by customers for microgroove records.
  3. Tape recording with condenser microphones became a long used standard operating procedure in mastering lacquer/aluminum cuts. This improved the overall pickup of high quality sound and enabled tape editing. Over the years there were variations in the kinds of tape recorders used such as the width and number of tracks employed, including 35 mm magnetic film technology.
  4. Production of stereo tape masters and the stereo LP in 1958 were quantum level improvements in recording technology.
  5. Limitations in the disc cutting part of the process generated the idea of half-speed mastering in which the source tape was played at half-speed and the lacquer/aluminum disc cut at 16 2/3 rpm rather than 33 1/3 rpm.
  6. Some 12 inch LPs were cut at 45 rpm claiming better quality sound, but this practice was short-lived.
  7. Efforts were made in the 1970s to record as many as four audio channels on an LP ("Quadraphonic") by means of matrix and modulated carrier methods. This development, though another quantum level improvement, was neither a widespread success nor long lasting.
  8. There were approaches to simplify the chain of equipment in the recording process and return to live recording directly to the disc master.
  9. Some records were produced employing noise reduction systems in the tape mastering as well as in the LP itself.
  10. As video recorders became perfected technically it became possible to modify them and use analog to digital converters (codecs) for digital sound recording. This enabled tape mastering with greater dynamic range, low noise and distortion, and freedom from drop outs as well as pre- and post-echo. The digital recording was played back providing a high quality analog signal to master the lacquer/aluminum cut.


At the time of the introduction of the compact disc (CD) in the mid-1980s, the stereo LP pressed in vinyl was at the high point of its development. Still, it suffered from a variety of limitations:
  • The stereo image was not made up of fully discrete Left and Right channels; each channel's signal coming out of the magnetic cartridge contained approximately 20% of the signal from the other channel. The lack of pure channel separation made for a sense of diminished soundstage.
  • Thin, closely-spaced spiral groove walls that allowed for increased playing time on a 33 rpm microgroove LP led to a tinny pre-echo warning of upcoming loud sounds. The hot tip of the cutting lathe unintentionally transferred some of the subsequent groove wall's impulse signal into the previous groove wall. It was discernible by some listeners throughout certain recordings but a quiet passage followed by a loud sound would allow anyone to hear a faint pre-echo of the loud sound occurring 1.8 seconds ahead of time. This problem could also appear as "post"-echo, with a tinny ghost of the sound arriving 1.8 seconds after its main impulse.
  • Fidelity steadily dropped as the recording progressed; there was more vinyl per second available for fine reproduction of high frequencies at the large-diameter beginning of the music groove than on the smaller diameter inner grooves closer to the center. The beginning of the music groove on an LP gave 510 mm of vinyl per second traveling past the stylus while the ending of the music groove gave 200–210 mm of vinyl per second—less than half the linear resolution.
  • Factory problems involving incomplete hot vinyl flow within the stamper could fail to accurately recreate a small section of one side of the groove, a problem called non-fill. It usually appeared on the first song of a side if it was present at all. Non-fill made itself known as a tearing, grating or ripping sound.
  • Poor vinyl quality control could put bits of foreign material in the path of the stylus, creating a permanent 'pop' or 'tick'.
  • The user setting the stylus down in the middle of a recording could cut into the groove and create a permanent 'pop' or 'tick'.
  • Dust or foreign matter collected on the record, making for multiple 'pops' and 'ticks' if not carefully cleaned.
  • A static electric charge could build up on the surface of the spinning record and discharge into the stylus, making a loud 'pop'. In very dry climates, this could happen several times per minute. Subsequent plays of the same record would not have pops in the same places in the music as the static buildup wasn't tied to variations in the groove.
  • An off-center stamping applied a slow 0.56 Hz modulation to the playback, affecting pitch due to a greater amount of vinyl per second on one side of the record than the other. It also affected tonality because the stylus is pressed alternately into one groove wall and then the other, making the frequency response change in each channel. This problem is often called "wow", though turntable and motor problems can also cause pitch-only "wow".
  • Motor problems or belt slippage could cause momentary pitch changes. If these repeated regularly, they could be called "flutter"; if they happened slowly they could be called "wow".
  • Turntable surface slickness, or the slickness of a stack of LPs could allow the top record to slip, causing momentary lowering of pitch in the playback.
  • Tracking force of the stylus was not always the same from beginning to end of the groove. Stereo balance could shift as the recording progressed.
  • Outside electrical interference could be amplified by the magnetic cartridge. Common household wallplate SCR dimmers sharing AC lines could put noise into the playback, as could poorly shielded electronics and strong radio transmitters.
  • Loud sounds in the environment could be transmitted mechanically from the turntable's sympathetic vibration into the stylus. Heavy footfalls could bounce the needle out of the groove.
  • Heat could warp the disk, causing pitch and tone problems if minor; tracking problems if major. Badly warped records would be rendered unplayable.
  • Because of a slight slope in the lead-in groove, it was possible for the stylus to skip ahead several grooves when settling into position at the start of the recording.
  • The LP was delicate. Any accidental fumbling with the stylus or dropping of the record onto a sharp corner could scratch the record permanently, creating a series of 'ticks' and 'pops' heard at subsequent playback. Heavier accidents could cause the stylus to break through the groove wall as it was playing, creating a permanent skip that would cause the stylus to either skip ahead to the next groove or skip back to the previous groove. A skip going to the previous groove was called a broken record; the same section of 1.8 seconds of LP music would repeat over and over until the stylus was lifted off the record.

LP versus CD

In the early days of compact discs, vinyl records were still prized by audiophiles because of better reproduction of analog recordings; however, the drawback was greater sensitivity to scratches and dust. Early compact discs were perceived by many as thin and sharp—distorting sounds on the high end. In some cases, this was the result of record companies issuing CDs produced from master recordings that were compressed and equalized for vinyl. Early consumer compact disc players may have contained 14-bit digital-to-analog converters, instead of the correct 16-bit type, as a cost-cutting measure. Some players were only linear to 10 or 12 bits.
Though digital audio technology has improved over the years, some audiophiles still prefer what they perceive as the sound of vinyl over CDs.
Proponents of digital audio state these differences are generally inaudible to normal human hearing, and the lack of clicks, hiss and pops from analog recordings greatly improved sound fidelity. Modern anti-aliasing filters and oversampling systems used in digital recordings have reduced the problems observed with early CDs.
The "warmer" sound of analog records is generally believed on both sides of the argument to be an artifact of harmonic distortion and signal compression. This phenomenon of a preference for the sound of a beloved lower-fidelity technology is not new; a 1963 review of RCA Dynagroove recordings notes that "some listeners object to the ultra-smooth sound as ... sterile ... such distortion-forming sounds as those produced by loud brasses are eliminated at the expense of fidelity. They prefer for a climactic fortissimo to blast their machines ..."
The theory that vinyl records can audibly represent lower frequencies that compact discs cannot (making the recording sound "warmer") is disputed by some and accepted by others—according to Red Book specifications, the compact disc has a frequency response of 20 Hz to 22.05 kHz(Although most current recordings do not utilize this spectrum, while the average human auditory system is sensitive to frequencies from 20 Hz to a maximum of around 20,000 Hz. This means that any frequencies that a vinyl record can represent that a compact disc cannot would be inaudible and thus completely subliminal yet contribute to the harmonic fidelity the lower frequency limit of human hearing can vary per person, and that interference caused by sound in the lower inaudible spectrum can still influence audible sound. It's possible that phonograph intermodulation effects from low frequency sources such as rumble and wow could adversely effect audible frequency ranges.



For the first several decades of disc record manufacturing, sound was recorded directly on to the master disc (also called the matrix, sometimes just the master) at the recording studio. From about 1950 on (earlier for some large record companies, later for some small ones) it became usual to have the performance first recorded on audio tape, which could then be processed and/or edited, and then dubbed on to the master disc.
A record cutter would engrave the grooves into the master disc. Early versions of these master discs were soft wax, and later a harder lacquer was used.
The mastering process was originally something of an art as the operator had to manually allow for the changes in sound which affected how wide the space for the groove needed to be on each rotation. Sometimes the engineer would sign his work, or leave humorous or cryptic comments in the lead-out groove area, where it was normal to scratch or stamp identifying codes to distinguish each master.

Mass producing

The soft master known as a lacquer would then be silvered using the same process as the silvering of mirrors, commonly the lacquer was sprayed with a saponin mix, rinsed, spraying with Stannous Chloride which sensitized the surface, rinsed again before the finally simultaneously spraying the Silver solution and dextrose reducer. This silver coating provided the conductive layer to carry the current for the subsequent nickel plating electroplated with a metal, commonly a nickel alloy. In the early days (1940–1960) the nickel plating was only brief, just an hour or less, before transferring to a copper plating tank. This was due to copper plating being both quicker and simpler to manage at that time. Later with advent of Nickel Sulphamate plating solutions all matrices were solid nickel. Most factories transferred the Master Matrix after an initial flash of Nickel in a slow warm nickel electroplating bath at around 15 ampere to a hot 130 degree Nickel plating bath where the amperage would be raised at regular intervals until the amperage reached between 110A and 200A depending on the standard of the equipment and the skill of the operators. This and all subsequent metal copies were known as matrices. When this metal master was removed from the lacquer (master), it would be a negative master or Master Matrix, since it was a negative copy of the lacquer. (In the UK, this was called the master; note the difference from soft master/lacquer disc above). In the earliest days the negative master was used as a mold to press records sold to the public, but as demand for mass production of records grew, another step was added to the process.
The metal master was then electroplated (electroformed)to create metal positive matrices, or "mothers". From these positives, stampers (negative) would be formed. Producing mothers was similar to electroforming Masters, except the time allowed to turn-up to full amperage was much shorter and the heavier Mothers could be produced in as little as one hour and stampers (145 grams) could be made in 45 minutes. Prior to plating either the Nickel Master or Nickel Mother it needed to be passified to prevent the next matrix adhering to the previous matrix. There were several methods used, EMI favoured the fairly difficult, Albumin soaking method where as CBS Records and Phillips used the Electrolytic method. Soaking in a di-chromate solution was another popular method. The electrolytic method was similar to the standard electrolytic cleaning method except the cycles were reversed finishing the process with Matrix as the anode. This also cleaned the surface of the matrix about to be copied. After separating from the Master a new mother was polished with a fine abrasive to remove or at least round-off the microscopic "horns" at the top of the grooves, produced by the cutting lathe. This allowed the vinyl to flow better in the pressing stage and reduced the non-fill problem. Stampers produced from the mothers after separating were chrome plated to provide a hard stain-free surface. Each stamper was next centre punched, methods used included aligning the final locked groove over three pins or tapping the edge while rotating under the punch until the grooves could be seen (through a microscope) to move constantly towards the centre. Either method was quite skilled and took much effort to learn. The centre punch not only punched a hole but formed a lip which would be used to secure the stamper into the press. The stamper was next trimmed to size and the back sanded smooth to ensure a smooth finish to the mouldings and improve contact between the stamper and the press die. The edge was then pressed hydraulically to form another lip to clamp the edge down on the press. The stampers would be used in hydraulic presses to mould the LP discs. The advantages of this system over the earlier more direct system included ability to make a large number of records quickly by using multiple stampers. Also, more records could be produced from each master since molds would eventually wear out.
Since the master was the unique source of the positive, made to produce the stampers, it was considered a library item. Accordingly, copy positives, required to replace worn positives, were made from unused early stampers. These were known as copy shells and were the physical equivalent of the first positive.
The "pedigree" of any record can be traced through the stamper/positive identities used, by reading the lettering found on the record run-out area.

Packaging and distribution

Singles are typically sold in plain or label-logo paper sleeves, though EPs are often treated to a cover in similar style to an LP. LPs are universally packaged in cardboard covers with a paper (usually additional artwork, photography, and/or lyrics) or plastic liner (or "poly-lined" paper) protecting the delicate surface of the record. Few albums have had records packaged inside with a 3 mil polyethylene plastic sleeve, either square or round-bottomed (also called "U" shaped), and an accompanying 11x11 paper insert with the additional artwork, photography, and/or lyrics as described above. The insert could be single- or double-sided, in color or grayscale, and glossy or matte.
Packaging methods have changed since the introduction of the LP record. The 'wrap-around' or 'flipback' sleeve initially became the standard packaging method for LPs during the 1950s. In this packaging method the front cover is able to be printed in colour and is laminated, whereas the back cover features only black text on a white background and is usually unlaminated. These sleeves are constructed in two parts: a laminated front section is wrapped around a separate back panel. Three 'flaps' are used to fix the front and back panels together on the outside. As the unlaminated cardboard back cover section is prone to discolouration due to exposure to natural light, in some instances a single printed sheet containing the back cover information is pasted over the entire back panel, covering the 'wrap-around' flaps but not reaching the outer edge of the sleeve, thus allowing some of the laminated 'flaps' to be exposed. Whilst discolouration still occurs with this method, it is often less evident than when the cardboard back cover alone is exposed.
Towards the end of the 1960s advances in printing and packaging technology lead to the introduction of the 'fully laminated' sleeve. Rather than the two-part construction of the 'wrap-around' sleeve, this method consists of a single component part, which is printed in full colour and is completely laminated with the 'flaps' tucked inside the back sleeve section. This is the method generally used for all subsequent releases in the vinyl age and is considered superior not only because of the additional ease allowed in the use of a single component, but also because the fully laminated finish offers far better protection from discolouration caused by exposure to natural light.
With the advent of long-playing records, the album cover became more than just packaging and protection, and album cover art became an important part of the music marketing and consuming experience. In the 1970s it became more common to have picture covers on singles. Many singles with picture sleeves (especially from the 1960s) are sought out by collectors, and the sleeves alone can go for a high price. LPs can have embossed cover art (with some sections being raised), an effect rarely seen on CD covers. The label area on the disc itself may contain themed or custom artwork rather than the standard record company's logo layout.
Records are made at large manufacturing plants, either owned by the major labels, or run by independent operators to whom smaller operations and independent labels could go for smaller runs. A band starting out might get a few hundred disks stamped, whereas big selling artists need the presses running full time to manufacture the hundreds of thousands of copies needed for the launch of a big album.
Records are generally sold through specialist shops, although some big chain stores also have record departments. Many records are sold from stock, but it is normal to place special orders for less common records. Stock is expensive, so only large city center stores can afford to have several copies of a record.
While records are generally pressed on plain black vinyl, the album itself is given a much more ornamental appearance. This can include a solid color (other than black), splatter art, a marble look, or transparency (either tinged with a color or clear). Some examples of this can be seen to the right. One of the most well known examples of this technique is the white vinyl repressing of The Beatles' White Album.


Record companies organised their products into labels. These could either be subsidiary companies, or they could simply be just a brand name. For example, EMI published records under the His Master's Voice (HMV) label which was their classical recording brand, Harvest for their progressive rock brand, home to Pink Floyd. They also had Music for Pleasure and Classics for Pleasure as their economy labels. EMI also used the Parlophone brand in the UK for Beatles records in the early 1960s.
In the 1970s successful musicians sought greater control, and one way they achieved this was with their own labels, though normally they were still operated by the large music corporations. Two of the most famous early examples of this were the Beatles' Apple Records and Led Zeppelin's Swan Song Records
In the late 1970s the anarchic punk rock movement gave rise to the independent record labels. These were not owned or even distributed by the main corporations. In the UK, examples were Stiff Records who published Ian Dury and the Blockheads and Two Tone Records, label for The Specials. These allowed smaller bands to step onto the ladder without having to conform to the rigid rules of the large corporations.

Home recording

The record enthusiast has two choices for creating a record. There are still some studios that allow the performer the option of recording a record. A disc cutting lathe is used to transfer a sound recording to a "reference lacquer" (commonly called an acetate or dub-plate). A new form of blank disc the "vinyl blank" has been introduced with varying results.
For someone seeking to make a single record, there is the option of purchasing a recording lathe and suitable record blanks. These machines can be occasionally found on online auctions. They allow the user to cut a record, which is afterwards playable on a turntable.
The first home phonograph disk recorders were introduced by RCA Victor in October 1930. These phonographs featured a large counter-balanced tone arm with horseshoe magnet pick-up. These types of pick-ups could also be "driven" to actually move the needle and RCA took advantage of that by designing a system of home recording that used "pre-grooved" records. The material that the records were made from (advertised as "Victrolac") was soft and it was possible to somewhat modulate the grooves using the pick-up with proper recording needle and a fairly heavy weight placed on the pick-up. The discs were only six inches in diameter so recording time at 78rpm was brief. Larger size Victor blanks were introduced late in 1931, when RCA-Victor introduced the Radiola-Electrola RE-57. These machines were capable of recording at 33 1/3 rpm as well as 78 rpm. One could select to record something from the radio or one could record using the hand-held microphone. The RAE-59 sold for a hefty $350.00 at a time when many manufacturers had trouble finding buyers for $50.00 radios.
The home phonograph disk recorders of the 1930s were expensive machines that few could afford. Cheaper machines, such as the Wilcox-Gay Recordio line, were sold during the late 1940s and early 1950s. They operated at 78 rpm only and were similar in appearance to (and not much larger than) a portable phonograph of the era. One 1941 model that included a radio sold for $39.95, approximately equivalent to $500 in 2005 dollars. The fidelity was adequate for clear voice recordings.
In the past (approximately from the 1940s through the 1970s), there were booths called Voice-O-Graphs, that let the user record their own voice onto a record when money was inserted. These were often found at arcades and tourist attractions alongside other vending and game machines. The Empire State Building's 86th floor observatory in New York City, Coney Island, NY and Conneaut Lake Park, PA are some of the locations which had such machines. Gem Razors also created thousands of free Voice-O-Graph records during wartime for the troops to send home to their families.
During the reign of the Communist Party in the former USSR, records were commonly homemade using discarded medical x-rays. These records, nicknamed "Bones", were usually inscribed with illegal copies of popular music banned by the government. They also became a popular means of distribution among Soviet punk bands; in addition to the high cost and low availability of vinyl, punk music was politically suppressed, and publishing outlets were limited.
Currently, two companies (Vestax and Vinylrecorder) offer disk recorders priced in the high four figures which enable "experienced professional users" and enthusiasts to produce high-fidelity stereo vinyl recordings. The Gakken Company in Japan also offers the Emile Berliner Gramophone Kit, and while it does not record actual records, it enables the user to physically inscribe sounds onto a CD (or any flat, smooth surface) with a needle and replay them back on any similar machine.
Home recording equipment made a cameo appearance in the 1941 Marx Brothers film, The Big Store. A custom recording was also the original surprise Christmas present in the 1931 version of The Bobbsey Twins' Wonderful Secret (when the book was rewritten in 1962 as The Bobbsey Twins' Wonderful Winter Secret, it became an 8 mm movie).


Due to the nature of the medium, playback of "hard" records, eg: LPs, causes gradual degradation of the recording. The recordings are best preserved by transferring them onto more stable media and playing the records as rarely as possible. They need to be stored on edge, and do best under environmental conditions that most humans would find comfortable. The medium needs to be kept clean — but use alcohol only on PVC or optical media, NOT on 78s. The equipment for playback of certain formats (e.g. 16 and 78 rpm) is manufactured only in small quantities, leading to increased difficulty in finding equipment to play the recordings. (This "gradual degradation" is more noticeable on some discs than others. In fact it is possible to have forty year old records that sound as new and brand new discs with pops and tics. How the records are handled and the equipment on which they are played as well as the manufacturing process and quality of original vinyl have a considerable impact upon their wear.) Where old disc recordings are considered to be of artistic or historic interest, record companies or archivists play back the disc on suitable equipment and record the result, typically onto a digital format which can be copied and converted without any further damage to the recording. For example, Nimbus Records uses a specially built horn record player to transfer 78s. However, anyone can do this using a standard record player with a suitable pickup, a phono-preamp (pre-amplifier) and a typical personal computer. Once a recording has been digitized, it can be manipulated with software to restore and, hopefully, improve the sound, for example by removing the result of scratches. It can also be easily converted to other digital formats such as DVD-A, CD and MP3.
As an alternative to playback with a stylus, a recording can be read optically, processed with software that calculates the velocity that the stylus would be moving in the mapped grooves and converted to a digital recording format. This does no further damage to the disc and generally produces a better sound than playback. This technique also has the potential to allow for reconstruction of damaged or broken disks.
With regard to inner sleeves, plastic polyethylene is purported to be better than the common paper sleeve and less bulky than the poly-lined paper variety. Paper sleeves deteriorate over time, leave dusty fibers, and produce static that attract dust. 100% poly sleeves produce less static (thereby attracting less dust), are archival, and are thinner by nature so they minimize pressure on the LP jacket seams.

Current status

Groove recordings, first designed in the final quarter of the 19th century, held a predominant position for an impressive amount of time—just about a century—withstanding competition from reel-to-reel tape, the 8-track cartridge and the compact cassette. However, by 1988, the compact disc had surpassed the gramophone record in popularity.
In spite of their flaws, such as the lack of portability, records still have enthusiastic supporters. Vinyl records continue to be manufactured and sold today, especially by independent rock bands and labels, although record sales are considered to be a niche market composed of audiophiles, collectors and DJs. Old records and out of print recordings in particular are in much demand by collectors the world over. (See Record collecting.) Many popular new albums are given releases on vinyl records and older albums are also given reissues as well, sometimes on audiophile grade vinyl with high quality sleeves.
In the UK, sales of new vinyl records (particularly 7 inch singles) have increased significantly in recent years, somewhat reversing the downward trend seen during the 1990s.
Many Electronic dance music genres such as Drum & Bass and Hip Hop are released almost entirely on Vinyl. This is because for disc jockeys ("DJs"), vinyl has an advantage over the CD: direct manipulation of the medium. DJ techniques such as slip-cueing, beatmatching and scratching originated on turntables. With CDs or compact audio cassettes one normally has only indirect manipulation options, e.g., the play, stop and pause buttons. With a record one can place the stylus a few grooves farther in or out, accelerate or decelerate the turntable, or even reverse its direction, provided the stylus, record player and the record itself are built to withstand it. Most CDJs and DJ software these days have these capabilities and many more, but despite this, the use of Vinyl for DJing is unlikely to ever die out.

Recording medium comparison

  • For many years, the Japanese Import pressings were considered to have the most accurate sound. The quality of these versions was due to a different process used to transfer the recording to vinyl.

See also



  • Lawrence, Harold; "Mercury Living Presence." Compact disc liner notes. Bartók, Antal Dorati, Mercury 432 017-2. 1991.
  • International standard IEC 60098: Analogue audio disk records and reproducing equipment. Third edition, International Electrotechnical Commission, 1987.
  • College Physics, Sears, Zemansky, Young, 1974, LOC #73-21135, chapter: Acoustic Phenomena
  • Powell, James R., Jr. The Audiophile's Technical Guide to 78 rpm, Transcription, and Microgroove Recordings. 1992; Gramophone Adventures, Portage, MI. ISBN 0-9634921-2-8
  • Powell, James R., Jr. Broadcast Transcription Discs. 2001; Gramophone Adventures, Portage, MI. ISBN 0-9634921-4-4
  • Powell, James R., Jr. and Randall G. Stehle. Playback Equalizer Settings for 78 rpm Recordings. Third Edition. 1993, 2001, 2007; Gramophone Adventures, Portage, MI. ISBN 0-9634921-3-6

Further reading

  • From Tin Foil to Stereo — Evolution of the Phonograph by Oliver Read and Walter L. Welch
  • The Fabulous Phonograph by Roland Gelatt, published by Cassell & Company, 1954 rev. 1977 ISBN 0-304-29904-9
  • Where have all the good times gone? — the rise and fall of the record industry Louis Barfe.
  • Pressing the LP record by Ellingham, Niel, published at 1 Bruach Lane, PH16 5DG, Scotland.
  • Sound Recordings by Peter Copeland published 1991 by the British Library ISBN 0-7123-0225-5.

External links

microgroove in Catalan: Disc fonogràfic
microgroove in Czech: Gramofonová deska
microgroove in Danish: Grammofonplade
microgroove in German: Schallplatte
microgroove in Spanish: Disco de vinilo
microgroove in Esperanto: Gramofondisko
microgroove in French: Disque phonographique
microgroove in Italian: Disco in vinile
microgroove in Hebrew: תקליט
microgroove in Latin: Phonodiscus
microgroove in Luxembourgish: Schallplack
microgroove in Hungarian: Hanglemez
microgroove in Macedonian: Грамофонска плоча
microgroove in Dutch: Grammofoonplaat
microgroove in Japanese: レコード
microgroove in Norwegian: Grammofonplate
microgroove in Norwegian Nynorsk: Grammofonplate
microgroove in Polish: Płyta gramofonowa
microgroove in Portuguese: Disco de vinil
microgroove in Russian: Грампластинка
microgroove in Slovenian: Gramofonska plošča
microgroove in Serbian: Грамофонска плоча
microgroove in Finnish: Vinyylilevy
microgroove in Swedish: Grammofonskiva
microgroove in Thai: แผ่นเสียง
microgroove in Ukrainian: Грамофонна платівка
microgroove in Chinese: 黑膠唱片
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