After Chrysler’s failed Highway Hi-Fi experiment, no other grandiose attempts at an in-car music system stuck. That is, until Earl “Madman” Muntz, an engineer and entrepreneur, pioneered 4-track cartridge technology (called the Stereo-Pak) and saw its potential for automotive. He introduced an inexpensively manufactured, sexily marketed stereo tape player, the Autostereo, which could play entire albums without skipping. This gave drivers control over their listening experience for the first time. Inventor Bill Lear (who worked on the Motorola radio decades earlier) expanded upon the 4-track technology and introduced Stereo 8 technology—better known as the 8-track cartridge system—commercially in 1965. Meanwhile, Philips launched the compact cassette in 1964, while the 8-track exploded in popularity due to its inexpensive cost.

Initially, the two had comparable sound quality, but the cassette tape’s quality steadily improved and, by the early ’70s, it easily bested the 8-track. Perhaps most importantly, the cassette was the most customizable format for in-car listening (and, with the advent of portable cassette players like the Walkman in 1979, for listening in general). Finally, individually created playlists were a possibility, and so began the age of the mixtape—a practice still beloved today.