The Muntz Stereo-Pak, commonly known as the 4- track cartridge, is a
magnetic tape sound recording An audio tape recorder, also known as a tape deck, tape player or tape machine or simply a tape recorder, is a sound recording and reproduction device that records and plays back sounds usually using magnetic tape for storage. In its present ...
cartridge technology. The Stereo-Pak cartridge was inspired by the Fidelipac 3-track tape cartridge system invented by George Eash in 1954 and used by radio broadcasters for commercials and jingles beginning in 1959. The Stereo-Pak was adapted from the basic Fidelipac cartridge design by Earl "Madman" Muntz in 1962 with Muntz partnering with Eash, as a way to play prerecorded tapes in cars.Jay Ehler
Earl Muntz Meets George Eash
Billboard vol. 84, No. 47, 18 November 1972, p. 62, 76, 78
The tape is arranged in an infinite loop which traverses a central hub and crosses a tape head, usually under a pressure pad to assure proper tape contact. The tape is pulled by tension, and spooling is aided by a lubricant, usually
graphite Graphite () is a crystalline form of the element carbon. It consists of stacked layers of graphene. Graphite occurs naturally and is the most stable form of carbon under standard conditions. Synthetic and natural graphite are consumed on lar ...


The endless loop tape cartridge was designed in 1952 by Bernard Cousino of
Toledo, Ohio Toledo ( ) is a city in and the county seat of Lucas County, Ohio, United States. A major Midwestern United States port city, Toledo is the fourth-most populous city in the state of Ohio, after Columbus, Cleveland, and Cincinnati, and accor ...
. Entrepreneur Earl "Madman" Muntz of Los Angeles, California, saw a potential in these broadcast carts for an automobile music tape system, and in 1962 introduced his "Stereo-Pak 4-Track Stereo Tape Cartridge System" and prerecorded tapes, initially in California and Florida. He licensed popular music albums from the major record companies and duplicated them on these 4-track cartridges, or CARtridges, as they were first advertised. Previously, music in the car had been restricted mostly to radios. Records, due to their methods of operation and size, were not practical for use in a car, although several companies tried to market an automobile record player including the
Highway Hi-Fi Highway Hi-Fi was a system of proprietary players and seven-inch phonograph records with standard LP center holes designed for use in automobiles. Designed and developed by Peter Goldmark, who also developed the LP microgroove, the discs utiliz ...
and the Auto-Com flexidisc


{{Audio format Audiovisual introductions in 1962 Audio storage Tape recording Discontinued media formats American inventions 1962 in music 1962 in technology Products introduced in 1962