Been messing with the vocoder.
This I found the settings to make a Battlestar Galactica Cylon voice.
Here are the settings.
Tone generator 40 hz square no alias.
Vocoder is default settings, except for amplitude of radar needles. Set this to 75.
I am attaching a sample file.
Sounds pretty good 
Hi, sorry to resurrect an old thread, but I had a go at replicating the effect with your settings but it sounded nothing like your sample. Can you tell me the exact setting and steps you took? Have the default settings changed in audacity since you posted this?
The Tone generator and Vocoder effect have been the same for many years.