History of Long Play Records-- Great Inventions
Early  history
RCA  logo with Nipper, the RCA/HMV dog.
A  sound recording and reproduction device utilizing what were essentially disc records  was described by Charles Cros of France in 1877 but never built. In 1878, Thomas  Edison independently built the first working phonograph, a tinfoil cylinder machine.  He intended it to be used as a voice recording medium, typically for office dictation.  The 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. They would dominate the market until the 1980s. Production of Amberol  cylinders ceased in the late 1920s.
Materials
Edison  cylinder phonograph ca. 1899
Early  disc records were originally made of various materials including hard rubber.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 records were the most common until  the 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.
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) 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  records were usually sold separately, in plain paper or cardboard sleeves that  may have been printed to show producer of the retailer's name and, starting in  the 1930's, in collections held in paper sleeves in a cardboard or leather book,  similar to a photograph album, and called record albums. Empty 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 33â…“ rpm record and the 45 rpm single records are made from vinyl plastic  which 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 inch (25 cm) and 12 inch (30 cm) diameter, and these were originally sold in  either paper or card covers, generally with a circular cutout allowing the record  label to be seen. The Long-Playing records (LPs) usually come in a paper  sleeve within a colour printed card jacket which also provides a track listing.  45 rpm singles and EPs (Extended Play) are of 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 record, marketed as "Program Transcription"  discs. These revolutionary discs were designed for playback at 33â…“ 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.[1]
However,  vinyl's lower surface noise level than shellac was not forgotten, nor was its  durability. In the late 30's, radio commercials and pre-recorded radio programs  being sent to disc jockies started being stamped in vinyl, so they would not break  in the mail. In the mid-40's, 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 (wax), particularly the six-minute 12" (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, on 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" (30 cm) Long Play (LP) 33â…“ 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.
A  Soviet-era "Bones" record, scratched onto a discarded x-ray print.
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.
Speeds
Earliest  rotation speeds varied widely, but between 1900-1925 most records were recorded  between 74-82 rpm. 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, which was the speed  at which a strobe disc with 77 lines would "stand still" in 50 Hz light. 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 33â…“ rpm (often just referred to as the 33 rpm), and the  45 rpm. The 33â…“ 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 Âµm) wide, compared  to 0.003" (76 Âµm) 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 16â…” 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.
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. 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". (See also format war )
Eventually  the 12" (300 mm) 33â…“ rpm LP prevailed as the predominant format for musical  albums, and the 7" (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 LP discs provided up to one half hour of time per side (though typically  15 to 20 minutes). The 45 rpm discs also came in a variety known as Extended play  (EP) which achieved up to 25 minutes play at the expense of attenuating (and possibly  compressing) the sound to reduce the width required by the groove.
From  the mid-1950s through the 1960s, in the US the common home "record player" or  "stereo" would typically have had these features: a three- or four-speed player  with changer (78, 45, 33â…“, and sometimes 16â…” 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.
Deliberately  playing or recording records at the wrong speed was a common amusement. For example,  playing the song "I'm on Fire" from Bruce Springsteen's 33â…“ LP at a 45 speed  gives the singer a falsetto singing voice that sounds very much like Dolly Parton.  Subsequently, playing a 45 rpm recording of Dolly Parton at 33â…“ gives her a  voice a husky, almost masculine tone.
Canadian  musician Nash the Slash took advantage of this speed/tonal effect with his 1981  12" disc Decomposing, which featured four instrumental tracks that were  engineered to play at any speed (with the playing times listed for 33â…“, 45 and  78 rpm playback). Faster playback made the tracks sound like punk rock or power  pop, while slower speeds gave the songs a thick, heavy metal effect.
 
Explanation
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.
Single-Record  (45 rpm)
12"  (30 cm) 45 rpm extended-playing ( 12-inch (30 cm) single ,  Maxi Single and EP ) format
12"  (30 cm) 78 rpm format, 4-5 minutes
10"  (25 cm) 78 rpm format, 3 minutes
7"  (17.5 cm) 45 rpm ( single ) format
7"  (17.5 cm) 45 rpm extended-playing ( EP ) format
 
Less  common formats
Structure  of a typical record
The  majority of 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.
200x  33 rpm vinyl record
Some  records are pressed on coloured vinyl or with paper pictures embedded in them  ("picture discs"). These discs can become collectors' items in some cases. During  the 1980s there was a trend for releasing singles on colour vinylâ€” 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  record standards for the United States follow the guidelines of the Recording  Industry Association of America (RIAA).[2] 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 (0.25â€³) 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. 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.
Progress,  and the war of the speeds
45  rpm records, like this one from 1955, often held a single - one especially  popular tune from a particular artist - with a flip side, a bonus for owners.
About  the same time the most common substance for making 33 rpm disc records became  vinyl, while 45 rpm discs were made from either vinyl or polystyrene. All speeds  of records were made in various sizes, mainly 17.5, 25, 30 cm (~7, 10 and 12 inches  diameter); the 17.5 cm (~7-inch) being most common for the 45 rpm, the 25 cm (~10-inch)  for the 78 (and the first few years of 33â…“ production), and the 30 cm (~12-inch)  for the 33 from the mid 1950s on.
Vinyl  quality
The  sound quality and durability of vinyl 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 /mÂ²)  process. Most vinyl records are pressed on recycled vinyl.
New  "virgin" or "heavy" (180-220 g/mÂ²) vinyl is commonly used for classical music,  although it has been used for some other genres. Today, it is increasingly common  in vinyl pressings that can be found in most record shops. Many classic rock albums  have been reissued on 180 g/mÂ² vinyl. Modern albums are also commonly pressed  on 180 g/mÂ². Many collectors prefer to have 180 gram 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 vinyl.
Since  most vinyl records are from recycled plastic, it can lead to impurities 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 be devoid  of the possible impurities of recycled plastic.
While  most vinyl records are pressed from metal master discs, a technique known as lathe-cutting  was introduced in the late 1980s by Peter King in Geraldine, New Zealand.[3] A lathe is used to cut microgrooves into a clear polycarbonate disc. Lathe cut  records can be made inexpensively in small runs. However, the sound quality is  significantly worse than proper vinyl records, and lathe cut records tend to degrade  further in quality after repeated playing.
Stereo  and beyond
In  1958 the first stereo two-channel records were issued â€“ 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.[4]
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 exploited  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.
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 quadrophonic 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.
Other  developments
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 NY Times music critic. The series of records  was then named â€œMercury Living Presence.â€� In 1955 Mercury began 3-channel  stereo recordings, still based on the principle of the single microphone. The  center (single) mic was of paramount importance, with the two side mics adding  depth and space. Record masters were cut directly from a 3-track to 2-track mixdown  console, with all editing of the master tapes done on the original 3-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.
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.
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.
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.
Also  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.
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.
 
 
Recording  the disc
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.
[ edit ] Mass producing records
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 negatives, stampers 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 record can be traced through the stamper/positive identities  used, by reading the lettering found on the record run-out area.
Packaging  and distribution
A  psychedelically coloured record.
Singles  are typically sold in plain paper wrappers, though EPs are often treated to a  cover in similar style to an LP. LPs are universally packaged in cardboard covers  with a paper liner protecting the delicate surface of the record. Also, 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. However, 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.
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.
 
Record  labels
Record  companies organised their products into labels. These could either be subsidiary  companies, or they could simply be just be 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 1960's.
In  the 1970's 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 1970's 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.
 
Disc  limitations
Shellac
Shellac  78's are brittle, and must be handled carefully. In the event of a 78 breaking,  the pieces might remain loosely connected by the label and still be playable if  the label holds them together, although there is a loud 'pop' with each pass over  the crack, and breaking of the needle is likely.
Breakage  was a very common accident in the shellac era. In the 1934 novel, Appointment  in Samarra, the protagonist "broke one of his most favorites, Whiteman's Lady  of the Evening ... He wanted to cry but could not." A poignant moment in J.  D. Salinger's 1951 novel The Catcher in the Rye occurs after the adolescent  protagonist buys a record for his younger sister but drops it and "it broke into  pieces ... I damn near cried, it made me feel so terrible."
[ edit ] Vinyl
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 the same  1.8 seconds of track (at 33â…“ rpm) over and over again. 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.
As  a practical matter, records provide excellent sound quality when treated with  care. They were the music source of choice for radio stations for decades, and  the switch to digital music libraries by radio stations has not produced a noticeable  improvement in sound quality. Casual ears cannot detect a difference in quality  between a CD and a clean new LP played in a casual environment with background  noise. 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). The limitations of recording and mastering techniques had a greater  impact on sound quality than the limitations of the record itself, at least until  the 1980s.
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"  singles were typically poorer quality for a variety of the reasons mentioned above,  and in the 1970s the 12" single, 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 2Â½ 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 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.
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 minimise 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).
At  high audible frequencies, hiss is generated as the stylus rubs  against the vinyl, and from dirt and dust on the vinyl.
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.
 
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 RIAA equalization since 1952, implemented in 1955. Prior  to that, especially from 1940, some 100 formulae were used by the record manufacturers.