Is changing pitch enough for anonymizing a person's voice? piqued my interest about digitally altering voices and the similarity to vocoders in music, and it just occurred to me: The carrier signal could be just about anything, right? So what prevents me from doing the exact same process described in the question but using someone else's singing voice as a carrier signal in order to imitate their voice?
This is just a guess but would I have to have a carrier signal that continuously changes in order to mimic their speech, since their formants/timbral information change over time in order to form words? Has this been achieved? If not, what makes it difficult?
My attempt to summarize the process vocoders use:
- The input signal (my voice) is separated into narrow intervals of frequency by way of the Fast Fourier Transform or something similar.
- The carrier signal (usually like a synth or something) has a specific pattern of overtones and harmonics that are different from the ones naturally present in the input (my voice)
- The input signal has every frequency band's amplitude (volume) altered to match the pattern that the carrier established
- The resulting frequency bands are combined to form the output signal