Free Zerius Vocoder Stand-Alone Software
This program is a free software channel vocoder, which imposes vocal effects on a waveform. It can be used to make your voice sound "robot-like", to create a singing synthesizer, to disguise your voice, and many other fun things. This effect has been made popular by artists such as Kraftwerk and Laurie Anderson, and is overused by Daft Punk.
This channel vocoder works by analyzing the frequencies in the modulator, splitting them into bands, finding the magnitude of each band, and then amplifying the corresponding bands of the carrier by that magnitude.
The modulator should simply be speech. It works best of you speak very clearly and more slowly than usual.
The carrier should be some kind of frequency rich waveform. White noise works well. Periodic white noise (i.e. a very short sample of white noise) gives a "robot-like" sound. Another one that sounds good is a synthesized string chord. This waveform will automatically be looped. You can get interesting results by having the waveform change over time.
That's all there is to it, really. Of course there are plenty of different ways to implement this. Most hardware and software vocoders use a series of band pass filters, envelope followers, and modulators to achieve the result.
My vocoder takes a different approach. It takes an FFT of the input signals, performs all its work in the frequency domain, and then does an inverse-FFT.
Download at: Zerius Vocoder Stand-Alone Software (Free)
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