Episode: 3767
Title: HPR3767: LP article from Wikipedia
Source: https://hub.hackerpublicradio.org/ccdn.php?filename=/eps/hpr3767/hpr3767.mp3
Transcribed: 2025-10-25 05:10:37

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This is Hacker Public Radio Episode 3,767 for Tuesday, 10 January 2023.
Today's show is entitled, LP Article from Wikipedia.
It is hosted by Archers 72 and is about 43 minutes long.
It carries an explicit flag.
The summary is LP Article from Wikipedia about the long playing vinyl record and its history.
Hello, this is Archers 72. Welcome to Hacker Public Radio.
In this episode, I'm reading from the Wikipedia Article on the LP or the long playing record.
The LP from long playing or long playing is an analog sound storage medium.
A phonograph record format characterized by a speed of 33 and a third RPM, a 12 or 10 inch,
30 or 25 centimeter diameter, uses the use of the micro-groove specification and a vinyl,
a copolymer of vinyl chloride acetate, composition disk, introduced by Columbia in 1948.
It was soon adopted as a new standard by the entire record industry.
Apart from a few relatively minor refinements and the important later addition of a stereophonic sound,
it remained the standard format for record albums during the period of popular music known as the album era,
until its gradual replacement from the 1980s to the early 2000s.
First by concerts then by compact discs and finally by digital music distribution.
Beginning in the late 2000s, the LP has experienced a resurgence in popularity.
The next section is format advantages.
At the time, the LP was introduced nearly all phonograph records for home use were made of an abrasive shellac compound,
which resulted in noisy playback.
They had much larger grooves and played at approximately 78 RPM,
limiting the playing time of a 12 inch diameter record to less than five minutes per side.
The new product was a 12 or 10, 30 or 25 centimeter fine-group disk made of PVC vinyl
and played with a smaller tipped micro-groove stylus at a speed of 33 and a third RPM,
each side of a 12 inch LP can play for about 22 minutes.
Only the micro-groove standard was new as both vinyl and 33 and a third RPM speed had been used for special purposes for many years,
as well as in one unsuccessful earlier attempt by RCA Victor to introduce a long playing record for home use.
Although the LP was suited to classical music because of its extended continuous playing time,
it also allowed a collection of 10 or more pop music recordings to be put on a single disk.
Previously, such collections, as well as longer classical music,
broken up into several parts, had been sold as sets of 78 RPM records,
and a specifically imprinted record album consisting of individual record sleeves bound together in a book form.
The use of the word album persisted for the one disk LP equivalent.
The next section is history, see also a phonograph record.
The subheading is soundtrack discs.
The prototype of the LP was the soundtrack discs used for the Vitafone Motion Picture Sound System,
developed by Western Electric and introduced in 1926 for soundtrack purposes.
The less than five minutes of playing time of each side of a conventional 12-inch 78 RPM disk was not acceptable.
The sound had to play continuously for at least 11 minutes,
long enough to accompany a full 1,000-foot 300-meter reel of 35-millimeter film projected at 24 frames per second.
The disk diameter was increased to 16 inches, 40 centimeters,
and the speed was reduced to 33 and a third revolutions per minute.
Unlike their microgrouped LP descendants, they were made with the same large standard group used by 78s.
Unlike conventional records, the group started at the inside of the recorded area near the label and proceeded outward toward the edge.
Like 78s, early soundtrack discs were pressed into an abrasive shellac compound and played with a single-use steel needle held in a massive electromagnetic pickup,
with a tracking force of two-ounce force 0.55 newtons.
A needle was used each time the film and the disk were played.
By mid-1931, all motion picture studios were recording on optical soundtracks,
but sets of soundtrack discs, mastered by dubbing from optical tracks and scaled down to 12 inches to cut costs,
were made as late as 1936 for distribution to theaters still equipped with disk-only sound projector.
The next heading under history is radio transcription discs.
From 1928 onwards, syndicated radio programming was distributed on 78 RPM discs.
The desirability of longer continuous playing time soon led to the adoption of the Vitafone sound track disk format, beginning in about 1930,
16 inch, 33 and a third RPM discs playing about 15 minutes per side were used for most of these electrical transcriptions.
Longer programs, which required several disk sides, pioneered the system of recording odd numbered sides inside, out and even numbered sides,
outside and so that the sound quality would match from the end of one side to the start of the next.
Although a pair of turntables was used to avoid any pauses for disk flipping, the sides had to be pressed in a range so that no disk being played had to be turned over to play the next side in the sequence.
For example, a three-disk set designed for manual sequencing would have the sides labeled 1, 2, 3, 4 and 5, 6,
and the listener would manually flip each disk as the side ended for an automatic record-changer turntable.
The sequencing would be 1 and 6, 2 and 5, and 3 and 4, with the listener flipping over the stack of disks once the third side ended.
In the broadcast sequence, the ordering would be 1 and 4, 2 and 5, and 3 and 6, so that the studio engineer could play side 1 on one turntable,
segged directly into side 2 on the second turntable, then queue up side 3 on the first turntable.
Some transcriptions were recorded with a vertically modulated hill and dale groove, also known as a vertical cut recording.
This was found to allow deeper bass because turntable rumble was laterally modulated in early radio station turntables,
and also an extension of the high frequency response.
Initially transcription disks were pressed only in Shalak, but by 1932,
Pressings in RC Victor's final bass Vectrola were appearing.
Other plastics were sometimes used by the late 1930s vinyl standard for nearly all kinds of press disks,
except ordinary commercial 78s, which continued to be made of Shalak.
Beginning in the mid 1930s, one off 16 inch, 33 and a third RPM lacquer disks were used by radio networks to archive recordings of their broadcasts,
and by local stations to delay the broadcast of network programming or to pre-record their own productions.
In the late 1940s, magnetic tape recorders were adopted by the networks to pre-record shows or repeat them after airing in different time zones,
but 16 inch vinyl pressings continued to be used into the early 1960s for non-network distribution of pre-recorded programming.
Use of the LP Marker groove standard began in the late 1950s and in the 1960s.
The size of the disk was reduced to 12 inches, becoming physically indistinguishable from ordinary LPs.
Unless the quantity required was very small, press disks were more economical, medium, for distributing high quality audio than tape,
and CD mastering was in the early years of that technology very expensive,
so use of the LP format transcription disks continued into the 1990s.
The King Biscuit Flower Hour is a late example as our Westwood ones, the Beatles years, and Dr. Demento programs,
which were sent to stations on LP at least through 1992.
Next heading, RCA Victor. RCA Victor introduced an early version of a long playing record for home use in September 1931.
These program transcription disks, as Victor called them, played at 33 on a third RPM and used a somewhat finer and more closely spaced groove than typical 78s.
They were to be played with a special chromium orange chrome-plated steel needle.
The 10-inch disks, mostly used for popular and light classical music, were normally pressed in shellac, but the 12-inch disks, mostly used for serious classical music, were pressed in Victor's new vinyl base, Victoralac compound, which provided a much quieter playing service.
These records could hold up to 15 minutes per side.
Beethoven's fifth symphony, performed by the Philadelphia Orchestra under Leopold Stakowski, was the first 12-inch recording issued, Compton, Peck and Sham, reviewing the event in the New York Times wrote,
while we were not prepared for was the quality of reproduction, and comparably fuller.
However, many of the subsequent issues were not new recordings, but simply Dubs made from existing 78 RPM records sets.
The Dubs were audibly inferior to the original 78s.
Two-speed turn tables with the 33- to 3rd RPM speed were included only on expensive high-end machines, which sold in very small numbers, and most people had little money to spend on groceries, let alone the phonograph record, in the depths of the Great Depression.
Record sales in the US had dropped from a high of 105.6 million records sold in 1921 to 5.5 million in 1933, because of the competition from radio and effects of the Depression.
Few of any new program transcriptions were recorded after 1933, and two-speed turn tables soon disappeared from RCA Victor's phonographs, except for a few recordings of background music for a few nor parlors.
The last of the issued titles had been purged from the Victor record catalog by the end of the decade.
The failure of the new product left RCA Victor with a low opinion of the prospects for any sort of long-playing record, influencing product development decisions during the coming decade.
CBS Laboratories had researched scientists Peter Goldmark, led Columbia's team to develop a phonograph record that could hold at least 20 minutes per side.
Although Goldmark was the chief scientist who selected the team, he delegated most of the experimental to work, to William S. Bachman, whom Goldmark had lured from General Electric and Howard H. Scott.
Research began in 1939, was suspended during World War II, and then resumed in 1945. Columbia records unveiled the LP at a press conference in the Waldorf Historia on June 18, 1948, in two formats, 10 inches, 25 centimeters in diameter, matching that of the 78 RPM single, and 12 inches, or 30 centimeters in diameter.
The initial release of 101 recordings were 58 12 inch classical LPs, M4000 to 4057, M4071, 12 10 inch classics, ML2001 to 2012, 12 inch light classic, ML4058 to 4067.
ML4060, ML4070, 8 10 inch light classic, ML2013 to ML2019, and 11 10 inch popular numbers, CL60001 to 6011.
According to Columbia's initial LP catalog, published in Billboard on 371948, all classical LPs were organized in alphabetical order of composers.
So this list is opened by ML4002 with Bach's concerto and D minor for two violins, and orchestra by Adolf Busch and Francis Magnus.
With the Busch Chamber players, concerto number two, and E major by Adolf Busch, with the Busch Chamber players, Columbia had planned for the album, ML4001 to be the LP opening the initial list of 101 LPs.
However, Bach's A minor violin concerto by Tibor Varga, foreseen foresight A could not be released on LP because of some contractual reasons, probably.
So without Bach, with Mendelssohn, ML4001 landed in alphabetical list under M like Mendelssohn.
The next heading is public reception. When the LP was introduced in 1948, the 78 was the conventional format for phonograph records.
By 1952, 78 still accounted for slightly more than half of the units sold in the United States, and just under half of the dollar sales.
The 45 oriented toward the single song accounted for just over 30% of unit sales and just over 25% of dollar sales.
The LP represented not quite 17% of unit sales and just over 26% of dollar sales. 10 years after their introduction, the share of unit sales for LPs in the US was almost 25%, and of dollar sales 58%.
Most of the remainder was taken up by the 45, 78 accounted for only 2% of unit sales and 1% of dollar sales.
The popularity of the LP ushered in the album error of English language popular music beginning in the late 1950s, as performers took advantage of the longer playing time to create coherent themes or concept albums.
The rise of the LP as a form, as an artistic entity, as they used to say, has complicated how we perceive that and remember what was once the most evanescent of the arts.
Robert Criscoll wrote in Criscoll's Records Guide, Rock Albums of the 70s, in 1981.
The album may prove a 70s totem, refer configurations, or making a comeback by decades and, but for the 70s, it will remain the basic musical unit, and that's okay with me.
I found over the years that the long playing record, with its 20-minute sides and 4-6 composition performances per side, suits my habits of concentration perfectly.
Although their popularity of LPs began to decline in the late 1970s, with the advent of compact cassettes and later compact discs, the LP survives as a format to present day.
vinyl LP records enjoyed resurgence in the early 2010s, vinyl sales in the UK reached $2.8 million in 2012, US vinyl sales in 2017 reached $15.6 million, and $27 million for 2020.
The next heading is competing formats. The LP was soon confronted by the 45, a 7-inch, 180-millimeter diameter, fine-groove vinyl record playing at 45 RPM, introduced by RCA Victor in 1949.
To compete with the LP boxed album sets of 45s were issued along with EP Extended Play 45s, which squeezed two or even three selections onto each side.
Despite intense marketing efforts by RCA Victor, 45 ultimately succeeded only in replacing the 78 as the preferred format for singles.
The last hurrah for the 78 RPM record in the US was the micro-goove 78 series, pressed for the audio file label, viewing none, sock-fill was constant in the early 1950s.
This series was labeled AP-1 through AP-40, pressed on grandless red vinyl.
Today, AP-1 through AP-5 are very scarce by tightly packing the fine groove, playing time a 17 minutes per side was achieved, within a couple of years audio file switched to 33 and a third.
Real to real magnetic tape recorders posed a new challenge to the LP in the 1950s, but the higher cost of pre-recorded tapes was one of the several factors that confined tape to a niche market.
Cartridge and cassette tapes were more convenient and less expensive than real to real tapes, and they became popular for use in automobiles beginning in the mid-1960s.
The LP was not seriously challenged as a primary medium for listening to recorded music at home until the 1970s.
However, when the audio quality of the cassette was greatly improved by better tape formulations and noise reduction systems, by 1983 cassettes were outselling Alps in the US.
The compact disc CD was introduced in 1982. It offered a recording that was theoretically completely noiseless and not audibly degraded by repeated playing or slight scuffs and scratches.
At first, much higher price of CDs and CD players limited their target to affluent early adopters and audio files, but prices came down and by 1988 CDs outsold Alps.
The CD became the top-selling format over cassettes in 1992. Along with phonograph records and other formats, some of which were made of other materials, Alps are now widely referred to simply as vinyl.
Since the late 1990s, there has been a vinyl revival.
Demand has increased in niche markets, particularly among audio files, DJs and fans of indie music.
But most music sales, as of 2018, came from online downloads and online streaming because of their availability, convenience and price.
The next heading is playing time. With the advent of sound film or talkies, the need for greater storage space made 33 and a third RPM records more appealing.
Soundtracks played on records synchronized to movie projectors and theaters could not fit onto the mere 5 minutes per side that 78s offered.
When initially introduced, 12 inch Alps played for maximum of about 23 minutes per side.
10 inch records for around 15. They were not an immediate success, however, as they were released during the height of the Great Depression and seemed ferviless to many impoverished of the time.
It wasn't until micro-groove was developed by Columbia Records in 1948 that long players, Alps, reached their maximum playtime which continued to modern times.
Economics and taste initially determined which kind of music was available on each format.
Recording company executives believed upscale classical music fans would be eager to hear a Beethoven Symphony or a Mozart concerto.
Without having to flip over multiple 4 minutes per side 78s, and that pop music fans, who are used to listening to one song at a time, would find
the shorter time of the 10 inch LP sufficient. As a result, the 12 inch format was reserved solely for high-priced classical recordings and Broadway shows.
Popular music continued to appear only on 10 inch records. Their beliefs were wrong by the mid-1950s, the 10 inch LP, like its similarly sized 78 RPM cousin, lost the format war and was discontinued.
10 inch records briefly reappeared as many Alps in the late 1970s in the early 1980s in the United States and Australia as a marketing alternative.
The next heading is exceptions. In 1952, Columbia Records introduced extended play Alps that played for as long as 52 minutes or 26 minutes per side.
These were used mainly for the original cast albums of Broadway musicals such as Kiss Me Kate and My Fair Lady, or to fit an entire play such as the 1950 production of Don Juan and Hell on two LPs.
52 minute playing time remained rare. However, because of mastering limitations and most LPs continued to be issued with a 30 to 45 minute playing time.
A small number of albums exceeded the 52 minute limit. These records had to be cut with much narrower spacing between the grooves, which allowed for a smaller dynamic range on the records and meant that playing the record with a worn needle could damage the record.
It also resulted in a much quieter sound with increased service noise.
The list of long playing vinyl records include the 90 minute, 1976 LP, 90 minutes with Arthur Fiedler and the Boston Pops made by Radio Shack.
Genesis Duke, with each side exceeding 27 minutes, Bob Dylan's 1976 album Desire, with the side 2 lasting almost 30 minutes, Deaf Luppards 1987 album hysteria, with each side exceeding 30 minutes, Iron Maiden's 1984 release, Power Slave, and its follow-up some more in time both required the special manufacturing as each surpassed the 52 minute maximum.
Todd Rungren's 1975 initiation totaling 67 minutes, 32 seconds over two sides, Paul Sputik, by the Beastie Boys and Andre Previn's Previn plays Gershwin, with the London Symphony Orchestra, whose sides each exceeded 30 minutes.
Side 2 of Pink Floyd's Adam Hart Mother, and both sides of the Division Bell, and Wings greatest, All Exceeded 28 minutes.
Finally, several recordings of Beth Olvins' 9th Symphony re-issued on single discs.
These LP's contained about 35 minutes on each side, with the third movement split into two parts.
Spoken Ward and Comedy albums required a smaller dynamic range compared to musical records, therefore they could be cut with narrower spaces between the grooves.
The comic strip, released by Springtime Records in 1981, has a side lasting 38 minutes, 4 seconds, and a side B lasting 31 minutes, 8 seconds, for a total of 69 minutes and 12 seconds.
The next heading is Changers.
Turn tables called Automatic Record Changers could play records stacked vertically on a spindle.
This arrangement encouraged the production of multiple record sets in automatic sequence.
A two record set had a side 1 and side 4 on one record, and side 2 and side 3 on the other.
So the first two sides could play in a changer without the listener's intervention.
An alternative type of record changer pushed the played disc off the turn table onto a hopper instead of having two discs drop on top of each other.
Then the stack was flipped over.
Larger box sets used appropriate automatic sequencing.
1 to 8, 2 to 7, 3 to 6, 4 to 5, to allow continuous playback, but this created difficulties when searching for an individual track.
Next heading, Disadvantages.
Vinyl records are vulnerable to dust, heat, warping, scuffs, and scratches.
Dust in the groove is usually heard as noise and may be ground into the vinyl by the passing stylus causing lasting damage.
A warp can cause a regular wow or fluctuation of musical pitch, and if substantial, it can make a record physically unplayable.
A scuff can be heard as a swishing sound.
A scratch will create an audible tick or pop once each revolution when the stylus encounters it.
A deep scratch can throw the stylus out of the groove.
If it jumps to a place farther inward, part of the recording is skipped.
If it jumps outward to a part of the groove, it just finished playing.
It can get stuck in an infinite loop, playing the same bit over and over until someone stops it.
This last type of mishap, which in the era of brittle shellac records, was more commonly caused by a crack,
spawned the similarly like a broken record to refer to annoying and seemingly endless repetition.
Records used in radio stations can suffer cue burn, which results from disc jockeys placing the needle at the beginning of a track,
turning the record back and forth to find the exact start of the music, then backing up and about a quarter turn,
so that when it is released, the music will start immediately after the fraction of a second needed for the disc to come to full speed.
When this is done repeatedly, the affected part of the groove is heavily worn and a hissing sound will be noticeable at the start of the track.
The process of playing a vinyl record with a stylus is by its very nature to some degree a destructive process,
where to either the stylus or the vinyl results in diminished sound quality.
Recordware can be reduced significantly by the use of a high quality, correctly adjusted turntable and tone arm.
A high compliance magnetic cartridge with a high end stylus and good condition, and careful record handling with non abrasive removal of dust,
before playing and other cleaning if necessary, where from playback is eliminated by use of an optical record player as no needle comes in contact with the record.
The next heading is groove. The average LP has about 1500 feet or 460 meters, 0.28 miles of groove on each side.
The average tangential needle speed relative to the disc surface is approximately 1 mile per hour or 1.6 kilometers per hour, which is 0.45 meters per second.
It travels fastest on the outside edge, unlike audio CDs which change their speed of rotation to provide constant linear velocity.
By contrast, CDs play from the inner radius outward the reverse of phonograph records.
Then closely spaced spiral grooves that allowed for increased playing time on a 33 and a third RPM micro groove,
LP led to a faint pre-oco warning of upcoming loud sounds.
The cutting stylus unavoidably transferred some of the subsequent groove walls and pull 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-eco of the loud sound occurring 1.8 seconds ahead of time.
This problem could also appear as post-eco with the ghost of the sound arriving 1.8 seconds after its main impulse.
Pre-imposed echo can be avoided by the use of direct metal mastering.
The first LP records introduced used fine pitch grooves just like their 78 predecessors.
The use of magnetic tape for the production of the master recordings allowed the introduction of variable pitch grooves.
The magnetic tape reproducer used to transfer the recording to the master disc was equipped with an auxiliary playback head positioned ahead of the main head by a distance equal to 1 revolution of the disc.
The sole purpose of this head was to monitor the amplitude of the recording.
If the sound level from both the auxiliary and magnetic heads was loud, the cutting head on the disc recording lathe was driven at its normal speed.
At the sound level from both magnetic heads was quieter, however then a disc cutting head could be driven at a lower speed reducing the groove pitch with no danger of the adjacent grooves colliding with each other.
The playing time of the disc was therefore increased by amount dependent on the duration of quieter passage.
The record manufacturers had also realized that by reducing the amplitude of the lower frequencies recorded in the groove, it was possible to decrease the spacing between the grooves and further increase the playing time.
These low frequencies were then restored to their original level on playback, furthermore if the amplitude of the high frequencies was artificially boosted on recording the disc.
Then subsequently reduced to their original level on playback, the noise introduced by the disc would be reduced by a similar amount.
This gave rise to an equalization frequency response.
Applied during record, coupled with an inverse of the response applied on playback, each disc manufacturer applied its own version of an equalization curve.
Mostly because each manufacturer's equalization curve was protected by interlocking patents.
Low end reproduction equipment applied a compromised playback equalization that reproduced most discs reasonably well.
By contrast, amplifiers for audio file equipment were equipped with an equalization selector with a position for most if not all disc manufacturers.
The net effect of equalization is to allow longer playing time and lower background noise while maintaining full fidelity of music or other content.
In 1954, the recording industry of America, RIA, introduced a standard equalization curve to be used by all record manufacturers.
Transsequently, both low quality and audio file reproducers alike could replay any recording with correct equalization.
There are two versions of the reproduction RIA equalization curve.
The first curve is the inverse of the recording curve designed for cheaper equipment using crystal or ceramic reproduction cartridges.
The second curve is intended for equipment fitted with magnetic reproduction cartridges, where the output voltage is dependent on the frequency of the recorded signal.
The voltage output is directly proportional to the frequency of the recorded signal, that is the voltage doubles as the recorded frequency doubles.
The next section is fidelity and formats.
The audio quality of LPs has increased greatly since their 1948 inception.
While early LP recordings were monophonic, Stereophonic has been demonstrated in 1881 and Ellen Bloomline had patented Stereophonic Sound in 1931.
Unsuccessful attempts were made to create Stereophonic records starting in the 1920s, including Emery Cook's 1952 Binaural LPs, using two precisely spaced tracks on the record, one track for each channel, that had to be played with two monoral pickups on a tuning fork shaped tone arm.
The modern system ultimately released by audio fidelity records in November 1957 uses two modulation angles, equal an opposite 45 degrees from vertical and so perpendicular to each other.
It can also be thought of as using traditional horizontal modulation with a sum of left and right channels mono, making it essentially compatible with simple mono recordings and vertical plane modulation for the difference of the two channels.
The following are some significant advances in the format.
Helium cooled cutting heads that could withstand higher levels of high frequencies, Numen SX68, previously the cutting engineer had to reduce the HF content of the signal sent to the record cutting head, otherwise the delicate coils could burn out.
Eliptical stylus marketed by several manufacturers at the end of the 1960s, cartridges that operated at lower tracking forces, 2.0 grams, per 20 milli newtons, beginning from the mid 1960s, half speed and one third speed record cutting, which extends the usable bandwidth of the record.
Longer lasting, anti-static record compounds, EG, RCA dynaflex Q540, more advanced stylus tip shapes, Shibata, Van DeHole, Microline, etc., direct metal mastering, noise reduction, CX encoding, DBX encoding starting from 1973.
In the 1970s, Quadrophonic sound or channel records became available in both discrete and matrix formats.
These did not achieve the popularity of stereo records due to the expense of consumer playback equipment, competing in incompatible quad recording standards and a lack of quality and quad remix releases.
Quad never escaped the reputation of being a gimmick, and the various mutually incompatible discrete surround solutions required an ultrasonic carrier signal that was technically difficult to capture and suffered degradation with playing.
With the advent of DV audio and super audio CD, multi-channel recordings once favored and chapping by artists like Leopold Stakowski and Glenn Gould have made it modest comeback.
In addition, new surround recordings have been made for these formats and Blu-ray audio.
In the later 1970s, engineers Jerry Block and Burgess McNeil devised a preview system of mastering vinyl that allowed about 10-20% more music per disc while not sacrificing dynamic range.
The preview tape head was positioned far enough before the program tape head to allow the disc computer enough time to measure the peaks in low frequency and thereby expand the feed appropriately for the greater excursions of groove modulations they produce.
The Compute Disc system was unveiled at the 1980 AES convention alongside the Zuma Disc computer made by John W. Bittner and the Newman VMS-80 lathe which had its own advanced disc computer.
The composition of vinyl used to press records, a blend of polyvinyl chloride and polyvinyl acetate, has varied considerably over the years.
Even vinyl is preferred, but during the 1970s energy crisis, it became commonplace to use recycled vinyl.
Sound quality suffered with increased ticks, pops, and other surface noises.
Other experiments included reducing the thickness of LPs leading to warping and increased susceptibility to damage.
Using a biscuit of 130 grams of vinyl had been the standard. Compare these to the original Columbia 12-inch LPs ML-4001 at around 220 grams each.
Besides the standard black vinyl specialty records are also pressed on different colors of PVCA or picture discs with a card picture sandwich between two clear sides.
Records in different novelty shapes have also been produced.
In 2018, an Austrian startup Rebeat Innovation GMBH received 4.8 million in funding to develop high-definition vinyl records that purport to contain longer playing times louder volumes and higher fidelity than conventional vinyl LPs.
Rebeat Innovation headed by CEO Gunter Loybel has called the format HD vinyl.
The HD process works by converting audio to a digital 3D topography map that is then inscribed on to the vinyl stamper via lasers, resulting in less loss of information.
Many critics have expressed skepticism regarding the cost and quality of HD records.
In May 2019 at the making vinyl conference in Berlin, Loybel unveiled the perfect groove software for creating 3D topographic audio data files.
This is a critical step in the production of HD vinyl stampers as they provide the map for subsequent laser engraving.
Audio engineering software was created with mastering engineers Scott Hull and Darcy Proper, a four-time Grammy winner.
The demonstration offered the first simulations of what HD vinyl records are likely to sound like.
Ahead of actual HD vinyl physical record production, Loybel discussed the perfect groove software at a presentation titled vinyl 4.0, the next generation of making records.
Before offering demonstrations to attend the final section is used by disc jockeys.
Disc jockeys or DJs in clubs still frequently use vinyl records as queuing tracks from cassette tapes is too slow and CDs do not allow creative until the advent of the CDJ 1000 turntable in 2001.
The term DJ which had always meant a person who played various pieces of music on the radio, originally 78s, then 45s, then tape cartridges and reels, now cuts from CDs or tracks on a computer.
A play on the horse racing term jockey has also come to encompass all kinds of skills in scratching record playback manipulation and mixing dance music, wrapping over the music or even playing musical instruments.
But the original dance club, non-radio definition, was simply somebody who played records alternating between two turntables.
The skill came in subtly matching beats or instruments from one song to the next, providing a consistent dance tempo.
DJs also made occasional announcements and chatted on the side with patrons while songs were playing to take requests, similar to what radio disc jockeys have been doing since the 1940s.
If you have gotten this far, thank you for listening to my reading of Wikipedia article on the LP record hosted by Hacker Public Radio. Until next time, bye.