

How does voice manipulation software work? - taphangum

I&#x27;ve been googling around for some good sources on this but haven&#x27;t had any luck.<p>Do any of you have any experience in this area, or could point me in the right direction with a good source?<p>I&#x27;d appreciate any help here!<p>Cheers
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mdturnerphys
I don't have any experience with this, but I'm a physicist with some
linguistics background, so I can make some guesses. Phonologists analyze
speech by looking at the formants [1]: spectral components of the sound that
are (typically) higher in frequency than the fundamental (i.e. pitch). The
formants are determined by the speaker's mouth and tongue shape, while the
fundamental is set by the vocal chords. If you want to change the pitch of a
speaker's (or singer's) voice but not change the speed or the phonemes
(fundamental speech sounds), then you need to change the frequency of the
fundamental while preserving the spectral envelope (on the harmonics of the
fundamental) set by the formants.

How to actually implement this becomes a question of signal processing. I have
an idea of how I might do it, but it would be pretty rough. I tried some other
Google search keywords and found a PDF [2] that gives one approach and might
be a good place to start.

[1]
[http://en.wikipedia.org/wiki/Formant](http://en.wikipedia.org/wiki/Formant)

[2] [http://dsp-book.narod.ru/Pitch_shifting.pdf](http://dsp-
book.narod.ru/Pitch_shifting.pdf)

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taphangum
Thank you very much for this very thorough answer! You've definitely helped me
look in the right direction.

