Voice types are rough categories which are used to describe singing voices with particular qualities. It is important to remember that these categories can sometimes be very vague, and it is possible for people to move between them, especially under the tutelage of a talented teacher. Most singers spend years developing their voices before entering performance, and it is common for instructors to refrain from categorizing their students until they have developed their voices more fully.
The basic voice types for women, from highest to lowest range, are: soprano, mezzo-soprano, and contralto. For men, the voice types are: counter tenor, tenor, baritone, and bass. Boys are considered to have treble voices, which will change as they enter puberty. Within each of these voice types, there is a great deal of range, and many musical traditions divide the voice types more precisely.
In addition to describing a singer's range with a voice type, people will also talk about the individual range of the singer, which can vary, along with the dynamics of his or her voice, and other unique qualities which can influence a singer's sound. Some singers have voices which are so distinctive that people can identify them instantly, and within the field of opera, some roles have even been written specifically for such voices, making them difficult for other singers.
Among sopranos, there is a great deal of variation. Coloratura sopranos are known for being able to hit the highest end of the soprano range, with light, clear voices which lend themselves well to ornate, complex music. Lyric sopranos are silkier, hitting the mid range, while dramatic sopranos hit the low end of the range, with dark, rich voices which can border on the mezzo-soprano. Mezzos are very common, and they often have dynamic, flexible ranges. Contraltos, on the other hand, are very rare, with rich, intense, almost grainy voices which can sound quite eerie.
The counter-tenor is the male equivalent of the contralto, and it is also an extremely rare voice type. Tenors have light, clear voices which are divided much like sopranos into categories like “lyric” and “dramatic.” The baritone is the most common male voice range, with a rich, mid-range voice which can be classified among a number of categories as well. Basses are the deepest male voices, with a rich, deep timber which often works well in comic roles.