What is a vocoder?
A Vocoder is most famously used to make your synthesizer talk and sing. The robotic-sounding voice is common in modern music and was first used by Stevie Wonder in the 1970s. The vocoder is not a regular feature on most synths, so do your research if it’s in your requirements.
The vocoder needs two different input signals to work, a carrier wave which was often the synthesizer itself with the use of anything from a clean analog sawtooth wave to a distorted, processed signal. The most common signal used is often a note, or notes, from the keyboard.
The second input is described as the modulator, this is where either your spoken or singing voice is recorded through the microphone attached to the vocoder. The vocoder analyzes the frequencies of your voice and then uses a bank of filters to create a similar shaped sound.
The end result is where the fun really starts, whatever you play on the keyboard will sound like it is speaking or singing whatever you are putting through the microphone at the same time. It will take a bit of practice but the potential is huge if you can master the art of the robotic voice!
The vocoder technology was originally invented for telecommunication purposes and was used successfully during World War II for encryption messages. However, musians saw the potential for creativity and it is now a regular addition to many modern songs.
Your voice is not the only sound source for the modulation signal, experimenting with other instruments can produce some mind-bending sounds! The carrier signal usually works best with big synth sounds that have depth, you’ll find long saw waves or string sounds are great for this.