Voice classification in non-classical music chart that follows. The ranges given below are approximations and are not meant to be too rigidly applied. Some men, in falsetto voice or as a result of certain rare physiological conditions, can sing in the same range as women. These do not fall into the female categories, instead called countertenors within classical music. Within contemporary music, however, the use of the term "tenor" for these male voices would be more appropriate. Teaching voice within non-classical music is an emerging field. Up to this point, voice teachers and voice research have been largely concentrated with classical methods of singing. However,
Voice type is quite resilient, especially in early adulthood, and the damage may not make its appearance for months or even years. Unfortunately, this lack of apparent immediate harm can cause singers to develop bad habits that will over time cause irreparable damage to the voice. Singing outside the natural vocal range imposes a serious strain upon the voice. Clinical evidence indicates that singing at a pitch level that is either too high or too low creates vocal pathology. According to vocal pedagogue Margaret Greene, "The need for choosing the correct natural range of the voice is of great importance in singing