Talk:Hatsune Miku/@comment-5012713-20120823161452/@comment-5017500-20120823192225

Vocaloids can sing in high range (or low range) which is impossible for their voice providers. Vocaloid's voice synthesis engine has a pitch shift algorithm. It uses the algorithm to make sounds in various pitches from a few sample voices.

But it may result an unnatural voice if the pitch shift amount is too large. So Vocaloid studios announce the optimum (recommended) range of each voicebank. But it is impossible to define "naturalness" in an objective way. Hence the optimum range is not absolute. Song creators often use their Vocaloids outside of their officially recommended range.