Revving Up the Vocoder Motor

Lately I've been working extensively with Logic Pro's vocoder, the EVOC 20 TrackOscillator, and have been very intrigued on how useful it is and the variety of different sounds you can make with it. A vocoder takes audible speech, encrypts it, and transmits it to a receiver which then resynthesizes it into a version of the original signal spectrum. (I know. Simple, right?) Basically, it can take a voice and play it through another sound. First developed in the 1930s, it wasn't until the 1970s and onward that it was applied to pop music, movies and television. Listen to these examples of vocoding from Disney-Pixar's Wall-E. A vocoder was used to take actress Ellisa Knight's voice and alter her vocal qualities to make her sound like a robot.

My application for it has been a little different though. Instead of a vocoding a human voice, I've been synthesizing two different sounds to create something new. For example, I take a lion's growl and side chain to large insect clicking sounds. Once I do that, I play around with the formant by shifting and stretching it, increase the vocoder signal, and then I have the beginnings of a huge, disgusting monster bug! It's a lot of fun just experimenting different sounds to see what you can create. It's also pretty cool to see how your favorite monster roars are created sometimes with sounds you'd never expect- like a pig squeal or crying babies.

To end, I leave you with a more recent example of musician Imogen Heap using a vocoder and a keyboard with her voice. By singing into a microphone which is fed into a vocoder and mapped out to her keyboard, she's able to imitate an electronic choir. It's beautiful.