The setting of the spectral interpolation determining slider 8 does not make much difference when the note
determining voltage changes slowly. When Slider 8 is on, the spectrum follows the original one a little better, but
because the analysis filterbank has good resolution, the fidelity is quite good also when it is off. Smoother spectral
interpolation helps to attenuate any possible clicks when the pitch changes rapidly (this is because there is no
synthesis filterbank that would smooth the time response, and the harmonic generator has very rapid response).
This vocoder has not been intended to be used as a high quality autotune. This is because the output pitch follows
faithfully the note played, rather than just trying to correct off-key singing, and the voice quality changes more than
in a dedicated autotune processor. Its use is mainly in special effects due to the versatile means to modify the
spectral parameters, and the means for live modulation using external envelopes. Definitely the most dramatic effect
is the big singer/small singer (timbre) adjustment and/or modulation, in the extreme cases when a small singer can
use very low pitch or a big singer a very high pitch. Also, the transient speedup possibility may be appreciated by
rap performers.
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