#7 INCH SINGLE RECORD 33 RPM FULL#

Longer programs, which required several disc sides, pioneered the system of recording odd-numbered sides inside-out and even-numbered sides outside-in so that the sound quality would match from the end of one side to the start of the next.

Beginning in about 1930, 16-inch 33 + 1⁄ 3 rpm discs playing about 15 minutes per side were used for most of these ' electrical transcriptions'. The desirability of longer continuous playing time soon led to the adoption of the Vitaphone soundtrack disc format. Radio transcription discs įrom 1928 onward, syndicated radio programming was distributed on 78 rpm discs. īy mid-1931 all motion picture studios were recording on optical soundtracks, but sets of soundtrack discs, mastered by dubbing from the optical tracks and scaled down to 12 inches to cut costs, were made as late as 1936 for distribution to theaters still equipped with disc-only sound projectors.

A new needle was used each time the film and disc were played. Like 78s, early soundtrack discs were pressed in an abrasive shellac compound and played with a single-use steel needle held in a massive electromagnetic pickup with a tracking force of 2 ounce-force (0.55 N). Unlike conventional records, the groove started at the inside of the recorded area near the label and proceeded outward toward the edge. Unlike their microgooved LP descendants, they were made with the same large 'standard groove' used by 78s. The disc diameter was increased to 16 inches (40 cm) and the speed was reduced to 33 + 1⁄ 3 revolutions per minute.

#7 INCH SINGLE RECORD 33 RPM FULL#

The sound had to play continuously for at least 11 minutes, long enough to accompany a full 1,000-foot (300 m) reel of 35 mm film projected at 24 frames per second. For soundtrack purposes, the less-than-five minutes of playing time of each side of a conventional 12-inch 78 rpm disc was not acceptable. The prototype of the LP was the soundtrack disc used by the Vitaphone motion picture sound system, developed by Western Electric and introduced in 1926. The use of the word 'album' persisted for the one-disc LP equivalent. Previously such collections, as well as longer classical music broken up into several parts, had been sold as sets of 78 rpm records in a specially imprinted 'record album' consisting of individual record sleeves bound together in book form. Īlthough the LP was suited to classical music because of its extended continuous playing time, it also allowed a collection of ten or more pop music recordings to be put on a single disc. Only the microgroove standard was new, as both vinyl and the 33 + 1⁄ 3 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.

Each side of a 12-inch LP can play for about 22 minutes. The new product was a 12 or 10-inch (30 or 25 cm) fine-grooved disc made of PVC ('vinyl') and played with a smaller-tipped 'microgroove' stylus at a speed of 33 + 1⁄ 3 rpm. Īt 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. Apart from a few relatively minor refinements and the important later addition of stereophonic sound, it remained the standard format for record albums (during a period in popular music known as the album era) until its gradual replacement from the 1980s to the early 2000s, first by cassettes, then by compact discs, and finally by digital music distribution.īeginning in the late 2000s, the LP has experienced a resurgence in popularity. Introduced by Columbia in 1948, it was soon adopted as a new standard by the entire record industry. The LP (from 'long playing' or 'long play') is an analog sound storage medium, a phonograph record format characterized by: a speed of 33 + 1⁄ 3 rpm a 12- or 10-inch (30- or 25-cm) diameter use of the 'microgroove' groove specification and a vinyl (a copolymer of vinyl chloride acetate) composition disk. Originally 23 minutes per side, later increased by several minutes, much longer possible with very low signal level

7 inch single record 33 rpm