A gramophone record is an analogue sound recording medium consisting of a flat disc with an inscribed modulated spiral groove. Gramophone records were the primary technology used for personal music reproduction for most of the 20th century. They replaced the phonograph cylinder in the 1900s, and although they were supplanted in popularity in the late 1980s by digital media.
A sound recording and reproduction device utilizing what were essentially disk 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, intending it for use as a voice recording medium, typically for office dictation. The phonograph cylinder dominated the recorded sound market beginning in the 1880s. Disc records were invented by Emile Berliner in 1888, and were used exclusively in toys until 1894, when Berliner began marketing disk records under the Berliner Gramophone label. The Edison "Blue Amberol" cylinder was introduced in 1912, with a longer playing time of around 4 minutes and a more resilient playing surface than its wax predecessor, but the format was doomed due to the difficulty of reproducing recordings. In the mid-1910s, disk records overtook cylinders in popularity, and would dominate the market until the 1980s. Production of Amberol cylinders ceased in the late 1920s.
Early disc records were originally made of various materials including hard rubber.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 which was 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. 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 Extended Plays (EPs) are of 7 inch (17.5 cm) diameter, the earlier copies being sold in paper covers. 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 at a constant rotational speed with a stylus placed in the groove, converting the vibrations of the stylus into an electric signal, and sending this signal through an amplifier to loudspeakers.
The sound quality and durability of vinyl records is highly dependent on the quality of the vinyl used. 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/m²) process. Most vinyl records are pressed on recycled 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 thus, will be immune from 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. 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.
Further information and links:Early Sound Recording and the Invention of the Gramophone
Emile Berliner - The History of the Gramophone
A History of the Gramophone Record