In 1951, a BBC outside broadcast unit brought a portable acetate disc cutter to the Manchester Computing Machine Laboratory and recorded three melodies played by Alan Turing's Mark II computer. The machine filled much of the ground floor. Today, only a 12-inch acetate disc survives — the computer was scrapped long ago, according to the British Library.
The recording had been playing at the wrong pitch for decades. Researchers Jack Copeland and Jason Long figured out the problem by analyzing what they called "impossible pitches" — frequencies the Mark II computer couldn't physically produce. The BBC's turntable had been running too fast during cutting, shifting everything sharp. Copeland and Long calculated the exact speed correction, filtered out noise, and removed wobble from the disc. "It was a beautiful moment when we first heard the true sound of Turing's computer," Copeland said.
Turing had discovered in the late 1940s that repeating the computer's "hoot" instruction in different patterns produced different musical notes. He used the tones as functional signals — one pattern meant a job was finished, another meant an error. Schoolteacher Christopher Strachey took it further, programming the first complete piece of computer music during an all-night session: "God Save the King." Turing's reaction: "Good show."
The BBC disc includes the National Anthem, "Baa Baa Black Sheep," and Glenn Miller's "In the Mood." An urban myth credits Bell Labs with the first computer music in 1957. Turing's lab beat them by six years.
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