“The vocoder—code name Special Customer, the Green Hornet, Project X-61753, X-Ray, and SIGSALY—started distorting human speech in earnest during World War II, in response to the excellence of German wiretapping. It worked by dividing a voice into its constituent frequencies and spreading it over ten channels, so that anyone who caught the message in transit would hear only noise. (German spies probably heard something like the droning of bees.) The cost of this security, however, was almost total destruction of the message itself: The voice, reassembled at the other end, came out sounding like a drunk robot. As Dave Tompkins puts it in his mind-altering new history of the technology—a book that has become a kind of underground legend in the ten years since he started working on it—the vocoder produced “an electronic impression of human speech: a machine’s idea of the voice as imagined by phonetic engineers.” Its early adopters were often driven to confusion, frustration, and existential dread. Still, the machine wound up robo-filtering some of the twentieth century’s most crucial conversations: FDR, Churchill, Truman, and JFK spoke through it to navigate D-day, the bombing of Hiroshima, and the Cuban Missile Crisis. Churchill, in particular, was a vocoder junkie. JFK, on the other hand, couldn’t figure out how to work its buttons. LBJ hated it so much he once threw his headset across Air Force One. The title of Tompkins’s book, How to Wreck a Nice Beach, is what the vocoder sounds like when it tries to say the phrase “how to recognize speech.”
More: Hi, Robot, The history of the vocoder, cryptography’s top-secret funk machine. New York Magazine.
