Before the advent of magnetic tape and digital CD technologies, flat disks made from a petroleum-based plastic called vinyl were the preferred media for popular music reproduction. Vinyl records replaced an even earlier system of wax-based cylinders which acted as both recording and playback units. By the 1920s, portable turntables called Victrolas and elaborately decorated record players had replaced the old cylinder players in most homes. Vinyl was found to be more durable than wax and much easier to store.
Vinyl records are formed at the end of a long recording process. Performers assemble in a special room designed to deaden extraneous noise. Vibrations from their voices or instruments are fed into an electronic microphone. As these vibrations are received, a wax disk spins at a designated speed. Originally this speed was 78 revolutions per minute with a ten-inch disk, but later the music industry adapted a 33 rpm speed for 12 inch (30 cm) disks and a 45 rpm speed for 7 inch (18 cm) disks, often called singles. Some spoken word albums actually turn at 16 rpm, but these albums are rare.
The wax disk spins at a constant speed while a sharp needle carves out a groove from the outside edge towards the inside. The vibrations from the recording session cause this needle to vibrate as it moves, recreating the sound waves of the original voices or instruments. This wax disk is used as the model for a master disk made from metal. Vinyl plastic is later melted and injected into the machine with the master disk. As the metal disk is pressed into the pliable vinyl, the groove is recreated precisely. A record player's needle picks up the vibration pattern in the groove and an electronic amplifier magnifies the sound for the listener. Even if a player is turned off, the action of the needle and the record can still reproduce some sound.
Vinyl records became popular for reasons other than storage and reproduction. Musicians discovered that the covers and sleeves used to protect the vinyl could also be used for artistic purposes. Songs could be compiled on 12 inch (30 cm) disks called albums, or smaller collections could appear on EPs, short for Extended Play. Popular songs from albums could be marketed as singles on 45 rpm disks.
Unfortunately, the fragile nature of vinyl records proved to be their commercial undoing. Cassettes made with durable magnetic tape became increasingly popular during the 1970s, followed by the revolutionary digital technology of the CD or compact disc. Vinyl records are still produced in small quantities for amateur musicians on a budget or performance artists who use vinyl records for an effect called scratching. Many people collect vinyl records as a hobby, preferring the organic sound of a record to the sterile but more perfect sound quality of a CD.