Vocal registration refers to the system of vocal registers within the human Voice. A register in the human Voice is a particular series of tones, produced in the same vibratory pattern of the vocal folds, and possessing the same quality. Registers originate in laryngeal function. They occur because the vocal folds are capable of producing several different vibratory patterns. Each of these vibratory patterns appears within a particular range of pitches and produces certain characteristic sounds. The term register can be somewhat confusing at it encompasses several aspects of the human Voice. The term register can be used to refer to any of the following:   Wikipedia