A quick look at the Korg Digital Voice Processor (DVP-1) from 1986, which was used by Air on numerous productions, including "Kelly Watch the Stars" from Moon Safari. The DVP was originally designed to give programmable voice effects at an affordable price, but you can run any audio signal you like through it. There's four main engines or "modes": Vocoder (as the name suggests, a digital vocoder) Harmonize (add five intervals to an audio signal, also has chord memory) Int Wave (internal digital waves that can be played via midi) Pitch Shift (digital pitch shifting) There's a built-in chorus effect, unison and poly modes and patch memory.