The 8-track cartridge, aka the Stereo 8, first appeared at trade shows in 1964, just 18 months after the cassette, and it did initially seem to have it all: it was comparatively small, portable, and had pretty good audio quality. And despite its roots in the Mad Men in-car market of the 1950s, it was seemingly future-proof, too, with a unique potential for quadraphonic sound (a potential later realised, in part). Within a few years various megastars were using it and it was swiftly installed in virtually every radio station in the western world—and, with rising domestic sales, it even had a massive ad campaign fronted by TV star Jimmie “Dy-no-mite!” Walker.

Yet within a few years of that expensive media blitz, the cartridge was dead in the water as far as the consumer market was concerned—and, by the mid-1990s, it was a rare antique even in broadcasting studios. What went wrong is easily explained with hindsight—though it seemed mysterious at the time.