Hi

pitch shifting does a pretty good job as long as you keep the transposition interval within 1/3rd of the root frequency of the sound you are processing. About +/- a minor or major third. The wider transposition you apply…the more artifacts you will get. This is so because only pitch is handled in the process. Formants need to be processed to get an exact transposition of the original sound. This is true for all pitch shifters in general. It's just part of how pitch shifting technology works.

best

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