What part of the vocal register does Hoedeck alternate with falsetto, that uses a particular part of the vocal range?
My Friend (Jacques Houdek song):  Houdek alternates between singing in Italian using his chest register and in English using his head and falsetto registers. Head voice: In vocal music, the head voice, depending on vocal pedagogy, is a particular part of the vocal range, or type of vocal register, or a vocal resonance area.
the head voice