A typical LP, showing its center label Media type Audio playback Encoding Analog grooves Capacity Typical 22-26 minutes per side; 2 sides Read mechanism Stylus Dimensions 12 in (30 cm); 10 in (25 cm) Weight 90-200 grams Usage Audio storage Extended from 1948 Long play (LP) record albums are 33S rpm vinyl phonograph records, generally either 10- or 12-inches in diameter. They were first introduced in 1948, and served as a primary release format for recorded music until the compact disc began to significantly displace them in the late 1980s. The long-playing record is an analog format. The digital recording of sound was only made practical by the technical advances in microprocessors and computing which occurred in the 1970s and 1980s. [edit] Physical and technical aspects Columbia Records unveiled the LP at a press conference in the Waldorf Astoria on June 21, 1948, the summer solstice and thus the longest day of the year, in two formats: 10in (25cm) in diameter, matching that of 78rpm singles, and 12in (30cm) in diameter.[1] Although they released approximately 50 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, and popular music appeared only on 10-inch records. Executives believed that whereas classical music aficionadoes 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, 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 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, twelve-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, due to mastering limitations, and most LPs continued to be issued with a 30- to 45-minute playing time throughout the lifetime of their production. Even so, the 45-minute play 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 fourteen minutes per side for ten-inch and 23 minutes per side for twelve-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 that 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. Records, like CDs, are easy to scratch. With a record, a scratch can cause popping sounds every time the record makes one revolution, at times even skipping to a previous groove and repeating information, or ahead and omitting information. 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 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] LP discs being delicate, as well as deceptively heavy for their size, people were less inclined to lug the significant weight of 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 in comparison with 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 approximately 1 mph on average. It travels fastest on the outside edge, unlike CDs, which change their speed of rotation to provide constant linear velocity. (Also, CDs play from the inner radius outward, the reverse of phonograph records.) The RIAA equalization curve (used since 1954) provides a de-emphasis in the bass notes, allowing closer spacing of record grooves and hence more playing time. Turntable cartridge preamplifiers 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 had one meaning of 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 floor tempo. DJs also made occasional announcements and chatted with patrons to take requests while songs were actually playing, similar to what radio disk jockeys have been doing since the 1940s. [edit] Fidelity and formats The audio quality of LPs increased greatly over time, and a small contingent of analog fans still maintain they are superior to digital media. Early LP recordings were monaural, but stereo LP records became commercially available in 1957. In the 1970s, quadraphonic sound (4-channel) records became available. These did not achieve the popularity of stereo records, partly due to scarcity of consumer playback equipment and partly due to the lack of quality in quad-remix releases. Quad never escaped the reputation of being a "gimmick". Besides the standard black vinyl, specialty records were also pressed on different colors of PVC (red, yellow, green, blue, white, clear, pink, multi-color and more) or special "picture discs" with a cardboard picture sandwiched between two clear sides. Records in different novelty shapes were also produced. Although most LPs played at 33S rpm, some "super fidelity" discs were designed to play at 45 rpm. There were also, early in the evolution of the LP, some records (primarily spoken word) designed to play at 16T rpm, and from the 1950s to the 1970s it was possible to purchase playback systems with four speeds: 16, 33, 45, and 78 rpm. The composition of vinyl used to press records varied considerably over the years. Virgin vinyl is preferred, but during the petrochemical crisis in the late 1970s it became commonplace to use recycled vinyl, melted unsold records with all the impurities. Sound quality suffered, with increased ticks, pops and other surface noises. Other experiments included reducing the thickness of LPs, leading to inherent warpage or increased susceptibility to damage. Using a bead of 130 grams of vinyl had been the standard, but some labels experimented with as little as 90 grams per LP. Today, high fidelity pressings follow the Japanese standard of 160, 180 or 200 grams. [edit] Reference ^ Marmorstein, Gary. The Label: The Story of Columbia Records. New York: Thunder's Mouth Press; p.165. v " d " e Audio formats Analog Phonautogram (1857) · Phonograph cylinder (1877) · Gramophone record (1895) · Wire recording (1898) · Reel-to-reel tape (1940s) · SoundScriber (1945) · Gray Audograph (1945) · Dictabelt (1947) · LP record (1948) · 45 rpm record (1949) · RCA tape cartridge (1958) · Fidelipac (1959) · Stereo-Pak (1962) · Compact Cassette (1963) · Stereo 8 (1964) · PlayTape (1966) · Mini Cassette (1967) · Microcassette (1969) · Steno-Cassette (1971) · Elcaset (1976) · Cassette single (1982) · Picocassette (1985) Digital Soundstream (1976) · 3M (1979) · X80/ProDigi (1980) · DASH (1982) · Compact Disc (1982) · Digital Audio Tape (1987) · ADAT (1991) · MiniDisc (1991) · Digital Compact Cassette (1992) · Extended Resolution Compact Disc (1995) · High Definition Compatible Digital (1995) · 5.1 Music Disc (1997) · Super Audio CD (1999) · DVD-Audio (2000) · K2 High Definition (2007) · USB flash drive (as audio format, 2004)