The male adolescent or changing voice is classified as either unchanged, changing incompletely, or changed (fully matured). The unchanged male adolescent voice range is approximately one and one-half octaves. The changing voice is between one to two octaves.
NOTE: The Adolescent Voice
The adolescent period includes the prepubertal years (7 to 9 years in boys) and the pubertal period (9 to 13 in girls; 12 to 15 in boys). Changes of voice quality, range, and pitch accompany the physical and emotional changes of this period. This is not a time for extensive vocal development, but rather for protecting and supporting the maturing instrument until it is ready for more rigorous training and performance. However, the adolescent years are ideal for aural development and study of music theory and composition, as well as participation in other musical activities, such as instrumental ensemble performance.