How To Wreck A Nice Beach: The Vocoder from World War II to Hip-Hop
by Dave Tompkins (Stop Smiling Books; $35)
World War II increased the rate of human innovation to a pace unseen in any other period of history. New technology from the era includes everything from synthetic rubber to the atomic bomb to magnetic audio tape, which the Germans successfully kept secret until the war’s end. After the Reich fell, Lt. Jack Mullin of the US Army Signal Corps shot footage outside of Hitler’s home, grabbed one of the Fuhrer’s piano strings for a souvenir, and brought two AEG Magnetophons (along with fifty reels of Farben recording tape) back with him to the states. He then sold a reel-to-reel tape recorder to Bing Crosby, revolutionizing broadcasting and music-making in the process. Another device that made its debut in World War II only to be later adopted by the entertainment industry is the Vocoder.
Speech synthesis was the brainchild of a Bell Labs employee named Homer Dudley. Dudley surmised that human speech consisted of two things: the carrier (the noise that your vocal cords makes) and the formant (the sound formed from the carrier by your mouth, throat, and sinuses). Dudley went on to develop something called the Voder (Voice Operator DEmonstratoR), which used a carrier tone generated by a radio valve and a formant created by hissing air to create artificial speech.
Not only could the Voder be hard to understand, it was difficult to operate. Dudley’s next project, the Vocoder, differs from its precursor in that it uses the formant generated by the operator’s voice and combines it with a carrier signal generated by a machine, in effect replacing the sound of your voice while keeping what you say intact. Since a carrier could be used that took up much less bandwidth than the human voice, this was obviously of great interest to the telecommunications industry. And eventually they would be adopted by companies to encode and decode to (and from) a digital format — but that wouldn’t be for many, many years. In the meantime, the technology would see its two great uses: encryption and popular music.
Despite its fame as a musical effect, the biggest thing the Vocoder ever did (literally!) was constitute the main component of the US Army’s SIGSALY encrypted communication system. In 1943, a single Vocoder channel (analogous to a single channel in a graphic EQ) was housed in a seven-foot tall rack tower. To secure communication, the operator’s voice would be encoded by the Vocoder and transmitted, along with randomly generated white noise that had been recorded on two phonographic records (the actual recording was made by the Muzak Corporation in Manhattan). As long as both parties were playing the same record — and they were perfectly synchronized — the system at the other end could decrypt the communication. In order to keep the vinyl in sync, Bell Labs developed both the turntables and its own time standard to ensure that the operators would be able to start and stop the rotation at precisely the same time. After one use, the acetates would be destroyed. According to Tompkins, a SIGSALY terminal consisted of forty racks of equipment, weighed 55 tons (including a five ton, nine foot tall air conditioner) and required a barge and an aircraft carrier to move. The system was used for conversations between FDR and Churchill, General Douglas MacArthur dragged one around the South Pacific in a ship, and a unit even found its way to the wine cellar of the St. George’s Hotel in Algiers. Twelve were deployed in total.
As time went on, the Vocoder got considerably smaller, and played its part in both the Cuban Missile Crisis and the Gulf of Tonkin incident. Eventually, it fell into civilian use, supplying the BBC Radiophonic Workshop with Daleks and lending its talents to popular music, from Wendy Carlos Williams’ score for A Clockwork Orange through Kraftwerk and Giorgio Moroder, before being adopted by electro, funk, and hip-hop producers (as well as electro-funk hip-hop producers). And this is the point where the author is obviously most comfortable, interviewing everyone from Rammellzee to Zapp’s Lester Troutman to Bill Sebastian (Sun Ra’s onetime keyboard player, inventor of the Outerspace Visual Communicator, and co-founder of Virtual Scene, the company that spawned Intelligent Compression Technologies; ICT was recently acquired by ViaSat for approximately $54.3 million).
Aside from the slices of Cold War history, How To Wreck A Nice Beach contains enough obscure hardware and obscure music to keep fans of both entertained for hours — and it draws a connection between the two that, while essential to understanding the role of technology in everyday life, is often something that we take for granted.
This article originally appeared on Engadget Alt.