THE HISTORY OF LP´s (LONG PLAY RECORDS)

CBS Laboratories head research scientist Peter Goldmark led Columbia's team to develop a phonograph record that would hold at least 20 minutes per side.[1] Columbia Records unveiled the LP at a press conference in the Waldorf Astoria on June 21, 1948 in two formats: 10 in (25 cm) in diameter, matching that of 78 rpm singles, and 12 in (30 cm) in diameter.[2] Although they released 100 simultaneously to allow for a purchasing catalogue, the first catalogue number for a ten-inch LP, CL 6001, was a reissue of the Frank Sinatra 78 rpm album set The Voice of Frank Sinatra; the first catalogue number for a twelve-inch LP, ML 4001, was the Mendelssohn Concerto in E Minor for Violin and Orchestra, Op. 64, played by Nathan Milstein with the Philharmonic-Symphony Orchestra of New York conducted by Bruno Walter. These two albums are therefore the first long-players.

Owing to marketing attitudes at the time, the 12-inch format was reserved solely for higher-priced classical recordings and Broadway shows; popular music appeared only on 10-inch records. Executives believed classical music aficionados would leap at the chance to finally hear a Beethoven symphony or a Mozart concerto without having to flip a seemingly endless series of four-minute per-side 78s, but popular music fans, used to consuming one song per side at a time, would find the shorter time of the ten-inch LP sufficient. This belief would prove to be mistaken in the end, and by the mid-1950s the 10 inch LP, like its similarly sized 78 rpm record, would lose out in the format wars and be discontinued. Ten-inch records would reappear as "extended-play" mini-albums in the late 1970s and early 1980s in the United States as a marketing alternative.

When initially introduced, 12-inch LPs played for a maximum of 45 minutes, divided over two sides. However, in 1952, Columbia Records began to bring out extended-play LPs that played for as long as 52 minutes, or 26 minutes per side. These were used mainly for the original cast albums of some Broadway musicals, such as Kiss Me, Kate and My Fair Lady, or in order to fit an entire play, such as the 1950 production of Don Juan in Hell, onto just two LPs. The 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 throughout the lifetime of their production. The longest known LP is Judy Garland's "Collectors Remembrance Album" with a playing time of 90 minutes.[citation needed]

Even so, the 45-minute playing time of the LP was a significant improvement over the previous dominant format, the 78 rpm single, which was generally limited to three to four minutes. At around 14 minutes per side for 10-inch and 23 minutes per side for 12-inch, LPs provided a measured time to enjoy a recording before having to flip discs.

Some record turntables, called record changers, could play a stack of records piled on a specially designed spindle and arm arrangement. Because of this, many multiple-record sets were released in what's called "automatic sequence." A two-record set would have 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, and then they could simply flip the stack over. Larger boxed sets used appropriate automatic sequencing (1+8, 2+7, 3+6, 4+5 for example) to allow for ease of continuous playback, but difficulties if searching for an individual track.

In contrast to compact disc players, very few record players (e.g., laser turntables) could provide a per-track programmable interface, so the record albums play in the same order every time. As the LP achieved market dominance, musicians and producers began to pay special attention to the flow from song-to-song, to keep a consistent mood or feel, or to provide thematic continuity, as in concept albums.

Vinyl records are much more vulnerable to being scratched than CDs. On a record, a scratch can cause popping sounds with each revolution when the needle meets the scratch mark. Deeper scratches can cause the needle to jump out of the groove altogether. If the needle jumps ahead to a groove further inward, information gets skipped. And if it jumps outward to the groove it just finished playing, it can repeat in an infinite loop, serving as the simile for things that continuously repeat ("like a broken record"). Additionally, records used in radio stations can suffer cue burn, which is a result of putting the needle on the record and then backing it up approximately a quarter turn so that it will play at the proper speed when the DJ starts the song. When this is done repeatedly, a hissing sound will preface the start of the actual song.

The large surface area of the record, being vinyl and therefore susceptible to becoming statically charged, pulls dust and smoke suspended particles out of the air, also causing crackles, pops and (in the worst cases of contamination) distortion during playback. Records may be cleaned before playing, using record cleaner and/or antistatic record cleaning fluid and anti-static pads. [1]

Since LP discs are delicate, as well as heavy for their size, people are less inclined to lug a stack of them around—for example, when visiting friends or when traveling—than a similar quantity of music compiled onto 90-minute cassettes compilation-tapes or today's digital formats.

The average LP has about 1,600 feet of groove on each side, or about a third of a mile. The needle travels from the outside to the center at approximately one mph, on average. It travels fastest on the outside edge, unlike most audio CDs, which change their speed of rotation to provide constant linear velocity (CLV). (By contrast, CDs play from the inner radius outward, the reverse of phonograph records.) This allows the lock groove effect used by The Beatles on Sgt Pepper's Lonely Hearts Club Band, on which the last track, A Day in the Life, runs into a continuous loop, that will repeat as long as the record player is on.

The RIAA equalization curve (used since 1954) de-emphasizes the bass notes, allowing closer spacing of record grooves and hence more playing time. Turntable cartridge pre-amplifiers reverse the RIAA curve to flatten out the frequencies again.

Disc jockeys (or DJs) in clubs still rely heavily on vinyl records, as there is no efficient way to cue tracks from cassette tapes, and CDs did not allow creative playback options until quite recently. The term "DJ," which has always meant a person who plays various pieces of music on the radio (originally 78s, then 45s, 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, rapping over the music or even playing musical instruments, but the original dance club (non-radio) definition was simply somebody who played records (LP tracks or 12" singles) in a club, 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 with patrons to take requests while songs were actually playing, similar to what radio disc jockeys have been doing since the 1940s.