A vocoder combines a recording of a human voice with a synthesized waveform to produce a robot-like effect. The Audacity free, open-source audio editing program includes a vocoder plug-in that you can use to produce this effect. Audacity’s vocoder requires you to create a stereo waveform with the vocal on the left channel and the synthesized sound on the right. The vocoder then modulates the left-hand channel with the right-hand one. Writer Bio
