Cassette tape

The Compact Cassette, also commonly called a cassette tape, audio cassette, or simply tape or cassette, is an analog magnetic tape recording format for audio recording and playback. Invented by Lou Ottens and his team at the Dutch company Philips and released in August 1963, Compact Cassettes come in two forms, either containing content as a prerecorded cassette (Musicassette), or as a fully recordable "blank" cassette. Both forms have two sides and are reversible by the user. Although other tape cassette formats have also existed—for example the Microcassette—the generic term cassette tape is normally used to refer to the Compact Cassette because of its ubiquity.

Its uses have ranged from portable audio to home recording to data storage for early microcomputers; the Compact Cassette technology was originally designed for dictation machines, but improvements in fidelity led to it supplanting the stereo 8-track cartridge and reel-to-reel tape recording in most non-professional audio applications by the mid-1970s. It became an extremely popular format for prerecorded music, first alongside the LP record and later the digital compact disc (CD); the latter format eventually caused prerecorded cassettes to fade into obscurity by the early 2000s in many countries, including the United States. The popularity of cassettes continued well into the 2000s in some other countries, including home recording purposes. Compact Cassette tapes remain in production as of 2024 and survive as an alternative to Vinyl format, continuing to receive some new music releases among popular artists.

The cassette was accompanied by two major tape playing innovations: the boombox and the Sony Walkman.

Compact Cassettes contain two miniature spools, between which the magnetically coated, polyester-type plastic film (magnetic tape) is passed and wound—essentially miniaturizing reel-to-reel audio tape and enclosing it, with its reels, in a small case (cartridge)—hence "cassette". These spools and their attendant parts are held inside a protective plastic shell which is 4 by 2.5 by 0.5 inches (10.2 cm × 6.35 cm × 1.27 cm) at its largest dimensions. The tape itself is commonly referred to as "eighth-inch" tape, supposedly 1⁄8 inch (0.125 in; 3.17 mm) wide, but actually slightly larger, at 0.15 inches (3.81 mm). Two stereo pairs of tracks (four total) or two monaural audio tracks are available on the tape; one stereo pair or one monophonic track is played or recorded when the tape is moving in one direction and the second (pair) when moving in the other direction. This reversal is achieved either by manually flipping the cassette when the tape comes to an end, or by the reversal of tape movement, known as "auto-reverse", when the mechanism detects that the tape has ended.