This Bob Heil–invented vocal-effects module is not a vocoder
by Peter Kirn
In an age in which robotic vocals have become cliche, the most important thing to know about the talk box is that it’s not a vocoder. That’s not to say the ideas aren’t related. The vocoder models human speech as the combination of a carrier and a formant—the sound of your vocal cords, and the way in which the physical shape of your throat, nose, and mouth filter that sound. In vocoders, these are reproduced entirely via electronic means. The talk box uses the formant you already have: your mouth. A speaker attached to a tube directs the sound of an instrument into the performer’s mouth, then amplifies the sound by way of a mic and output. Move your mouth as you would when speaking, and your mouth becomes a low-tech, real-time filter for the sound.
The beauty of this system is that it is immediate and physical, a kind of cyborg technology, capable of modulating any sound. Whereas artists like Daft Punk are most closely associated today with talk boxes, its origins lie in the era before computers or robots, in artificial speech research and the explosion of experimentation with the sound of the guitar.
Bell Labs perhaps deserves credit for the first talk-box-style invention, the 1929 artificial larynx, which used a metallic vibrating reed as a stand-in for vocal cords. The artificial larynx was, of course, a medical remedy, so it required an opening called the stoma in the speaker’s throat—not a terribly convenient solution for a musician.
Musicians found they could simply get a speaker near the mouth, then mic the results so they could be amplified. By the 1930s, swing musician Alvino Rey was already changing the sound of guitars with a modified pedal steel guitar; Rey even worked with Gibson to produce their first electric guitar. As early as 1939, he wired a talk-box-style mic effect to create a “singing guitar”—a guitar sound with formants shaped by the mouth. To play up the novelty on variety shows, he even created a guitar puppet as a character to represent the anthropomorphic instrument and hid his wife behind a curtain to perform the modulation.
Nineteen thirty-nine also happens to be the year fiction writer and former radio operator Gilbert Wright invented his Sonovox. The Sonovox used speakers pressed into the throat to produce mechanical talking sounds, including the singing train in the Disney movie Dumbo, and stories like Sparky’s Magic Piano. With the mouth as filter, any sound could be made to “talk.”
The talk box caught on as a guitar effect in the ’70s, in songs like Joe Walsh’s “Rocky Mountain Way.” Bob Heil had the foresight to add amplification to the effect, and made the Heil Talk Box the first commercial product—and the name stuck. You can still buy the Heil piece, though other models have come and gone. Because you need only a speaker, a mic, a filter, and some kind of tube or other connection, almost anyone can create a talk box—a recent viral YouTube video uses the Korg DS-10 handheld Nintendo game and a drinking straw. The one thing you can’t do is make a digital model. Real talk boxes require real mouths, though digital effects (including vocoders and vocoder-like effects such as the discontinued DigiTech Talker) have tried. That said, given the relatively predictable results of voice correction, the talk box is proof that ingenious thinking and real-world processing can yield endless variety.
Peter Kirn edits the website createdigitalmusic.com.