Vinyl Music Records
History of Vinyl Music Records
Early disc music 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 excretion 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. Shellac music records were the most common until the 1950s. Unbreakable music 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.
In the 1890s the early recording formats of discs were usually seven inches (nominally 17.5 cm) in diameter. By 1910 the 10-inch (25.4cm) music 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 (30.5cm) were also commercially sold, mostly of classical music or operatic selections, with four to five minutes of music per side.
Such music records were usually sold separately, in plain paper or cardboard sleeves that may have been printed to show the producer or the retailer's name and, starting in the 1930s, in collections held in paper sleeves in a cardboard or leather book, similar to a photograph album, and called record albums. Empty music record albums were also sold that customers could use to store their records in.
While a 78 rpm record is brittle and relatively easily broken, both the microgroove LP 33? 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. 78s come in a variety of sizes, the most common being 10 inches (25 cm), and 12 inches (30 cm) in diameter, (sometimes 6–8 inches in the UK), and these were originally sold in either paper or card covers, generally with a circular cutout allowing the record label to be seen. 45 rpm singles and EPs (Extended Play) are of a 7-inch (17.5 cm) diameter, the earlier copies being sold in paper covers.
In 1930, RCA Victor launched the first commercially available vinyl long-playing music record, marketed as "Program Transcription" discs. These revolutionary discs were designed for playback at 33? rpm and pressed on a 30 cm diameter flexible plastic disc. Vinyl had the advantage of lower surface noise level than shellac and was more durable.
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" (30 cm) Long Play (LP) 33? rpm microgroove record album was introduced by the Columbia Record at a dramatic New York press conference. In 1949, RCA Victor released the first 45 RPM single, 7" 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 music records were made from either vinyl or polystyrene.
The earliest rotation speeds varied widely. Most music 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 music record marked as "Speed D". It is one of these CLV disks.
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.
Columbia and RCA's competition extended to equipment. Some turntables included spindle size adapters, but other turntables required snap-in inserts like this one to adapt RCA's larger 45 rpm spindle size to the smaller spindle size available on nearly all turntables.
After World War II, two new competing formats came on to the market and gradually replaced the standard "78": the 33? rpm (often just referred to as the 33 rpm), and the 45 rpm. The 33? 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" (25 µm) wide, compared to 0.003" (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 preamplifier with multiple selectable equalization curves.
A number of recordings were pressed at 16? RPM, 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 still common to see turntables with a 16 RPM speed setting produced as late as the 1970s.
The older 78 music record format continued to be mass produced alongside the newer formats into the 1950s, and in a few countries, such as India, into the 1960s. 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" (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".
From the mid-1950s through the 1960s, in the U.S. the common home "record player" or "stereo" would typically have had these features: a three- or four-speed player with changer (78, 45, 33?, and sometimes 16? rpm); a combination cartridge with both 78 and microgroove styluses; and some kind of adapter for playing the 45s with their larger center hole. The large center hole on 45s allows for easier handling by jukebox mechanisms. RCA 45s can also be adapted to the smaller spindle of an LP player with a plastic snap-in insert known as a "spider"; such inserts were prevalent starting in the 1960s.
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 disc recording, on stereo music records the stylus moves vertically as well as horizontally.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. 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.
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 35mm magnetic film instead of half-inch tape for recording. The greater thickness and width of 35mm 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 music 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
The early 1980s saw the introduction of "dbx-encoded" music 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.
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.
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. 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 music 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.
Some music records are pressed on coloured vinyl or with paper pictures embedded in them ("picture discs"). 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" singles a viable format.
Vinyl music 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?) 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") 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 Spice by Eon), 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.
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 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.
The sound quality and durability of vinyl music records is highly dependent on the quality of the vinyl. During the early 1970s, as a cost-cutting move towards use of lightweight, flexible vinyl pressings, much of the industry adopted a technique of reducing the thickness and quality of vinyl used in mass-market manufacturing, marketed by RCA Victor as the "Dynaflex" (125 g/m²) process, considered inferior by most record collectors. Most vinyl records are pressed on recycled vinyl.
New "virgin" or "heavy" (180-220 g/m²) vinyl is commonly used for modern "audiophile" vinyl releases in all genres. Many collectors prefer to have 180 g/m² vinyl albums, and they have been reported to have a better sound than normal vinyl. These albums tend to withstand the deformation caused by normal play better than regular vinyl180 g/m² vinyl is more expensive to produce and requires higher-quality manufacturing processes than regular vinyl.
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 the possible impurities of recycled plastic. 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 direct metal mastering (DMM) the master disc is cut on a copper-coated disc which can also have a minor "orange peel" effect. As this "orange peel" originates in the master rather than being introduced in the pressing stage, there is no ill-effect.
While most vinyl music records are pressed from metal master discs, a technique known as lathe-cutting is used to create the master discs. A lathe is used to cut microgrooves into a lacquer disc. A mold is then made from the lacquer disc out of nickel, this is called a stamping record. Lathe cut records are commonly used for small runs and was the dominant format for audio archiving before the wide spread use of tape.
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 run-off groove area, where it was normal to scratch or stamp identifying codes to distinguish each master.
The soft master known as a lacquer would then be electroplated with a metal, commonly a nickel alloy. This and all subsequent metal copies were known as matrices. When this metal was removed from the lacquer (master), it would be a negative master 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 to create metal positive matrices, or "mothers". From these positives, stampers (negative) would be formed. 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 music record can be traced through the stamper/positive identities used, by reading the lettering found on the record run-out area.