Gramophone record
Articleissues | article=y
long = little
refimprove = May 2007
cleanup = August 2008
A gramophone record (also known as phonograph record, or simply record) is an analog
Types of records
As recording technology evolved, more specific terms for gramophone or phonograph records would be used to emphasize some aspect of the record, often its nominal rotational speed ("16 2/3 rpm", "33 1/3 rpm", "45 rpm", "78 rpm") or the material used (particularly "vinyl" to refer to records made of
Sizes of records in America and the UK are generally measured in
History
multi-listen item
filename=Au Clair de la Lune (1860).ogg
title=Au Clair de la Lune
description= This 1860
format=
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,
This
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
As early as 1894,
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." [cite book|title=The Recording and Reproduction of Sound, Revised and Enlarged Second Edition|author=Oliver Read|publisher=Howard W. Sams & Co., Inc.|location=Indianapolis|year=1952, chapter 2, "History of Acoustical Recording." Introduction of speed governors, p. 12; 1898 hand-cranked Victrola with governor, fig. 2-6, p. 14; "literature does not disclose why the standard speed of 78 rpm was chosen," p. 15]
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.
When a
"Electrical" recording
During the 1920s, engineers, particularly at
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." [Wanamaker's ad, "The New York Times," January 16, 1926, p. 16] 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. [Pakenham, Compton (1930), "Recorded Music: A Wide Range". "The New York Times," February 23, 1930, p. 118]
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
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. ["New Music Machine Thrills All Hearers At First Test Here." "
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
78 rpm disc size
In the 1890s the early
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 two minutes, the same as early cylinder records.Millard, Andre, [http://books.google.com/books?id=gd2b0M2fDckC&pg=PA353&dq=record+playing+time&lr=&as_brr=3&sig=7-b5dyw-qWHnsJbSCQUgg6bAN7I#PPA58,M1 America on Record: A History of Recorded Sound] . For example, when King Oliver's Creole Jazz Band, including By 1938, when Another way around the time limitation was to issue a selection on both sides of a single record. Vaudeville stars An obvious workaround for longer recordings was to release a set of records. The first multi-record release was in 1903, when 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 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 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 horizontally or stood upright on an edge, but because of their fragility, many broke in storage. German record company By about 1910 [A catalogue issued in 1911 by Barnes & Mullins, musical-instrument dealers of London, illustrates examples in both 10″ and 12″ sizes; one is shown containing two records issued by 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 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 There was 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 hours long.Fact|date=May 2008 However, vinyl's lower surface noise level than Beginning in 1939, Dr. Peter Goldmark and his staff at On a small number of early phonograph systems and Speeds The earliest rotation speeds varied widely. Most records made in 1900–1925 were recorded at 74–82 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 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 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 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 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 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 Deliberately playing or recording records at a higher speed gave an antic quirkiness to voices; doing so 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 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 Stereo sound In 1958 the first stereo two-channel records were issued—by Audio Fidelity in the USA and Pye in Britain, using the 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. [cite web|url=http://www.vinylrecorder.com/stereo.html|title=Stereo disc recording|accessdaymonth=4 October |accessyear=2006] 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: This system was invented by 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, The development of In the late 1970s and 1980s, a method to improve the 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 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 Laser turntable Formats Common formats 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 Structure 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. The last part of the spiral meets an earlier part to form a 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 The majority of non–78 rpm records are pressed on black Some records are pressed on coloured vinyl or with paper pictures embedded in them ("picture discs"). 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 with 7-inch singles. Vinyl record standards for the United States follow the guidelines of the 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 " The catalog number and stamper ID is written or stamped in the space between the groove in the lead-out on the master disc, resulting in visible recessed writing on the final version of a record. Sometimes the cutting engineer might add handwritten comments or their signature, if they are particularly pleased with the quality of the cut. When auto-changing turntables were commonplace, records were typically pressed with a raised (or ridged) outer edge and a raised label area. This would allow records to be stacked onto each other, gripping each other without the delicate grooves coming into contact, thus reducing the risk of damage. Auto changing turntables included a mechanism to support a stack of several records above the turntable itself, dropping them one at a time onto the active turntable to be played in order. Many longer sound recordings, such as complete operas, were interleaved across several 10-inch or 12-inch discs for use with auto-changing mechanisms, so that the first disk of a three-disk recording would carry sides 1 and 6 of the program, while the second disk would carry sides 2 and 5, and the third, sides 3 and 4, allowing sides 1, 2, and 3 to be played automatically; then the whole stack reversed to play sides 4, 5, and 6. Vinyl quality The sound quality and durability of vinyl records is highly dependent on the quality of the New "virgin" or "heavy" (180–220 g) vinyl is commonly used for modern "audiophile" vinyl releases in all Since most vinyl records are from recycled plastic, impurities can be accumulated in the record, causing a brand new album to have audio artifacts like clicks and pops. Virgin vinyl means that the album is not from recycled plastic, and will theoretically be devoid of these impurities. In practice, this depends on the manufacturer's quality control. The "orange peel" effect on vinyl records is caused by worn moulds. Rather than having the proper mirror-like finish, the surface of the record will have what looks like an orange peel texture. This introduces noise into the record, particularly in the lower frequency range. It should be noted that with While most vinyl records are pressed from metal discs known as 'stampers', a technique known as lathe-cutting is used to create the original discs. A lathe is used to cut microgrooves into an aluminium disc coated with a soft lacquer. This lacquer disc is then electroplated with nickel to form a negative known as a 'master' disc, which has a protrusion rather than a groove. The lacquer disc is destroyed when the nickel impression is separated. This master disc is then electroplated with nickel to form a positive disc known as a 'mother'. Many mothers can be grown from a single master before the master deteriorates beyond use. In their own turn the mothers are nickel plated to produce more negative discs known as 'stampers'. Again a single mother can grow many stampers before they deteriorate beyond use. It is these stampers that are then used to mould the final vinyl discs. [ [http://www.madehow.com/Volume-5/LP-Record.html How LP record is made] from madehow.com] In this way several million vinyl discs can be produced from a single lacquer original. For production of discs where a relatively small quantity is required, the first nickel negative grown from the lacquer original is used directly as a stamper. Production by this latter process (known as the 'half process') is limited to a few hundred vinyl discs. Limitations Shellac Breakage was very common in the shellac era. In the 1934 novel, " Another problem with Shellac was that the size of the disks tended to be larger due to the fact that it was limited to 80-100 groove walls per inch before the risk of groove collapse became too high, whereas vinyl could have up to 260 groove walls per inch. [http://www.bbc.co.uk/music/features/vinyl/1940/ BBC Music - 1940's Vinyl] (accessed 22/06/2008)] [http://theofficialcharts.com/album_chart_introduction.php Official UK Charts Co. - Album info] (accessed 22/06/2008)] Vinyl Vinyl records do not break easily, but the soft material is easily scratched. Vinyl readily acquires a static charge, attracting Vinyl records can be warped by 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 (sometimes referred to as a "doughnut"), manufactured at both 33 1/3 and 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 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.Fact|date=September 2007 The 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.Fact|date=September 2007 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 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, At high audible frequencies, 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). Equalization 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 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 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 ( 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 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; 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. hortcomings At the time of the introduction of the LP versus CD In the early days of Though 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 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. 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. The lower frequency limit of human hearing can vary per person, and interference caused by sound in the lower inaudible spectrum can still influence audible sound. It's possible that phonograph Production Recording 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 A record cutter would engrave the grooves into the master disc. Early versions of these master discs were soft 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 positive/stamper 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 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 Towards the end of the 1960s advances in With the advent of long-playing records, the 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. Labels Record companies organised their products into labels. These could either be subsidiary companies, or they could simply be just a brand name. For example, 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' In the late 1970s the anarchic Home recording One example of an "instantaneous recording" machine, available to the home recording enthusiast by about 1929 or 1930, was the "Sentinel Chromatron" machine.The "Sentinel Chromatron" machine for recording on uncoated aluminum is described as part of a " RCA Victor introduced home phonograph disk recorders 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 During the reign of the Communist Party in the former Currently, two companies ( Home recording equipment made a cameo appearance in the 1941 Preservation 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 eighty year old records that sound as new as 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, 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 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. [cite web|url=http://reviews.ebay.com/How-to-Protect-your-Vinyl-Records-Sleeve-Selection_W0QQugidZ10000000002588902?ssPageName=BUYGD:CAT:-1:LISTINGS:2|title=How to Protect your Vinyl Records - Sleeve Selection|accessdaymonth=6 april|accessyear=2008] 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 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 In the UK, sales of new vinyl records (particularly 7 inch singles) have increased significantly in recent years, [cite web|url=http://www.thebusinessonline.com/Document.aspx?id=AF137CB5-26C3-42ED-B0A9-A053E5544208|title=Back in the groove|publisher=The Business Online.com|author=Tony Glover|date=2006-05-14|accessdaymonth=14 January |accessyear=2007] [cite web|url=http://www.telegraph.co.uk/news/main.jhtml?xml=/news/2006/09/17/nsing17.xml|title=Why singles are top of the pops again |publisher=Telegraph.co.uk|author=Chris Hastings|date=2006-09-17|accessdaymonth=4 October |accessyear=2006] somewhat reversing the downward trend seen during the 1990s. Many In India, vinyl was discontinued in the early 1990s, however, a sizable backlog of titles has resulted in continued popular use of the vinyl LP.Fact|date=June 2008 Notes and references Specific notes and references: General references: Further reading *"From Tin Foil to Stereo — Evolution of the Phonograph" by Oliver Read and Walter L. Welch External links * [http://eil.com/explore/guide/vinyl_making.asp Creating a vinyl record] from eil.com
*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.
# 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.
# 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.
# 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.
# Production of stereo tape masters and the stereo LP in 1958 were quantum level improvements in recording technology.
# 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.
# Some 12 inch LPs were cut at 45 rpm claiming better quality sound, but this practice was short-lived.
# Efforts were made in the 1970s to record as many as four audio channels on an LP ("
# There were approaches to simplify the chain of equipment in the recording process and return to live recording directly to the disc master.
# Some records were produced employing noise reduction systems in the tape mastering as well as in the LP itself.
# 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.
*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
*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. [ [http://audacityteam.org/forum/viewtopic.php?f=26&t=102&start=0&st=0&sk=t&sd=a&view=print Audacity Team Forum: Pre-echo when recording vinyl record] ] 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. [ [http://www7a.biglobe.ne.jp/~yosh/jis_s8502.htm Comparative tables for 30 cm LP Standards] ]
*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 (1.3 if 45 rpm) music would repeat over and over until the stylus was lifted off the record.
*cite journal | author=Fadeyev, V., and C. Haber | title= [http://www-cdf.lbl.gov/~av/JAES-paper-LBNL.pdf Reconstruction of mechanically recorded sound by image processing] | journal=Journal of the
*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,
*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
*"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
* [http://www.youtube.com/watch?v=hjKlFFp4-IE Record Making With Duke Ellington (1937)] from
* [http://www.kiddierecords.com/ Kiddie Records Weekly] — Recordings and case images from children's records of the 1940s and 1950s.
* [http://www.russian-records.com/ The Encyclopedia of Russian pre-Revolutionary Recordings] Discography and Forum dedicated to early Russian recordings
* [http://vinylfanatics.com/ Vinylfanatics.com] Current news and reviews to do with Gramophone records. Also a forum.
* [http://www.rfwilmut.clara.net/repro78/repro.html Reproduction of 78 rpm records] including equalization data for different makes of 78s and LPs.