Before the cassette truly hit the American mainstream in the late 1970s, the premier format for portable music was developed after the invention of the cassette itself. William Lear, of Learjet fame, was a distributor of Earl Muntz’s “Stereo-pak” cartridge system.¹ Muntz had revised a previous design for a three-track magnetic tape cartridge used by radio stations for commercials into a four-track cartridge for automobile stereos.² Lear, who installed the same cartridge players in his jets, was frustrated by the consistent jamming of the Stereo-paks and began to redesign them. Lear was able to double the tracks on a tape in a cartridge while simplifying the design of the cartridge itself. The “8-track” tape was able to hold twice the recording time compared to Muntz’s design – 80 minutes compared to 40 minutes – at the cost of fidelity.³ Regardless, Lear worked with Ford Motor Company to introduce 8-track stereo systems into Ford’s vehicles for 1966. The move paid off, and by 1968, nearly 2.5 million 8-track stereos were in use across the United States. While acceptable for its portability and music capabilities, the 8-track tape lacked many of the conveniences provided by home stereo tape systems, such as fast-forward, reverse, and simple recording features.⁴ Despite the resulting popularity of home tape systems, the 8 track tape remained the dominant form of portable music listening up until the late 1970s. The 8-track tape serves as the most prominent and similar cultural ancestor to the cassette, cementing magnetic tape technology as the foremost analog format for portable music enjoyment.