The two minutes of tones might sound unfamiliar to a modern computer user, but back in the day, audio tones were used to communicate over phone lines and to load and save programs via cassette tape recorders. You might be asking yourself: why the ZX Spectrum? Radiohead is from the UK, but that’s not the complete picture. Of all home computers, the ZX Spectrum had a higher effective bit rate when storing data on tape. Basically, it takes less time (and less tape) to put it on a Speccy than a C64 or Apple.
Radiohead didn’t invent this gimmick. There’s a long history of record albums sneaking in software as audio tones, including a single from [Frank Sidebottom] when he was still going by [Chris Sievey] that had an animated “music video” on a Sinclair ZX back in 1983 (see the second video, below).
You might think this was the first time Radiohead has appeared on Hackaday. After all, we aren’t really a music site. But you’d be wrong. If you don’t have a ZX Spectrum lying around, you can always go the FPGA route.