These timbres are produced by classical training techniques with which most popular singers are not intimately familiar, and which even those that are do not universally employ them.
In the United States, the term contemporary commercial music (CCM) is used by some vocal pedagogues.
These basic types are soprano, mezzo-soprano, and contralto for women, and tenor, baritone, and bass for men.
[6] Within choral music the system is collapsed into only four categories for adult singers: soprano and alto for women, and tenor and bass for men.
Children's voices, both male and female, are described as trebles, although the term boy soprano is widely used as well.
First, the traditional definitions of the different voice types were made with the assumption that singers would be using classical vocal technique.
[8] “These differences in voice qualities are reflections on variation in the muscular, aerodynamic, and acoustical conditions in the larynx and in the vocal tract.
The choral system was developed to delineate polyphonic structure and was not really intended to designate a vocal type to individual singers.
[5] For example, most women that sing the alto line in choirs would be considered mezzo-sopranos in opera due to their vocal timbre and their particular range resting somewhere in the middle between a soprano and contralto.
[1] Most people's voices fall within the middle categories of mezzo-soprano for women and baritone for men.
[1] Some men, in falsetto voice or as a result of certain rare physiological conditions, can sing in the same range as women.
However, new approaches and methods to teaching non-classical voice have recently emerged, such as the complete vocal technique (CVT)[10] by Cathrine Sadolin at Complete Vocal Institute or speech level singing (SLS)[11] by Seth Riggs.