What was with the "robot voice" in disco music, and how come they don't do that anymore?

Its a device called a vocoder. sid9_gci213626%2C00.html,http://whatis.techtarget.com/definition/0,,sid9_gci213626,00.html Vocoders went out of fashion, but they do turn up from time to time in recent music. The current microKorg synthesiser is one instrument that includes a vocoder. http://www.sonicstate.com/articles/article.cfm?id=57

In case that first link doesn't work http://en.wikipedia.org/wiki/Vocoder

I thought it was a MOOG synthisizer.

BTW...the "Classic" Cylons sound like the robots from the videogame "Berzerk"

It needs to be plugged into an instrument, and the synthesiser (Moog or otherwise) was a common one for that purpose, and necessary for the Cylon voice. But it could just as well be plugged into a guitar, producing a sound Frampton make famous.

A similar device is the ring modulator, which the BBC Radiophonic Workshop used to create the voices of hthe Daleks & other aliens on Dr Who, Blake's 7, Hitchhikers Guide To The Galaxy etc.

The "Cylon" voice effect was also heard as far back as 1967 in a "Captain Scarlet and the Mysterons" episode.

The "Funky-town" song used that type of voice effect too.

Another robot voice effect can be created by using the equipment used by people who have had throat surgery & cannot speak normally. Robert the Robot for Fireball XL5, Dr Who's early Cybermen are good examples, but the first might have been Sparky's Magic Piano.

Sometimes DJs will use a Speak and Spell as part of their...ehm...what do you call those goofy segments that they use when proadcasting their station ID? <:S