The vocoder, also known as the “voice box”, is an electronic device that is used to distort natural vocal sounds.

How does it work?
A vocoder needs two inputs to function properly. A ‘carrier’ wave, and a ‘modulator’ input. The carrier is the sound you want to vocode through, and the modulator is your voice. The modulator takes your voice, finds the fundamental frequencies (important bits) of it, and converts them into levels of amplitude on a series of band pass filters (this is why some vocoders have different numbers of bands) – in general, the more bands available the more understandable your speech will be. These band pass filter signals are then passed onto the carrier wave where your final sound is created.
The vocoder is very popular amongst genres, but significant use of the vocoder is prominent in the funk era. Artists like Zapp and Roger and Roger Troutman (separately) used to vocoder to enhance their music and take funk to a higher level.