Stereo-Pak
| Media type | Magnetic tape cartridge |
|---|---|
| Encoding | Analog signal |
| Read mechanism | Tape head |
| Write mechanism | Magnetic recording head |
| Developed by | Earl Muntz |
| Usage | Car audio playback |
| Released | 1952 |
The Muntz Stereo-Pak, commonly known as the 4-track cartridge, is a magnetic tape sound recording cartridge technology.
The Stereo-Pak cartridge was inspired by the Fidelipac 2-track monaural (audio & cue tracks, later 3-track for stereo) tape cartridge system invented by George Eash in 1954 and used by radio broadcasters for commercials and jingles in 1959. The Stereo-Pak was adapted from the Fidelipac cartridge design by Earl "Madman" Muntz in 1962, in partnership with Eash, as a way to play pre-recorded tapes in cars.
The tape is arranged in an infinite loop that 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.