Soprano and mezzo-soprano comprise the higher registers in female voice tones. Soprano pieces in opera often go to heroines, due to the innocent quality of a higher pitched voice, according to the National Endowment for the Arts. The soprano voice is separated into two different sounds: dramatic and lyrical, depending on the intensity of the singer's voice.
Mezzo-soprano voices make up the middle section of the female register. Often, mezzo-soprano tone roles go to maternal, villainous or seductive roles, as well as in the roles of young men.
The lowest of the female tones, contralto singers are rare, according to the National Endowment for the Arts. Usually, contralto opera roles go to witches or older women.
Countertenor and tenor make up the high ranges of male voice tones. Countertenor roles often portray young, innocent men (much like soprano for women). Additionally, countertenor tones show sexual youth.
Tenor tones often create a soft, loving feeling, meaning that many hero's parts use tenor singers. Just as soprano splits into two categories, tenors also divide into lyrical and dramatic tenors.
Baritone, baritone-bass and bass comprise the three lower male tones. As the main male character in an opera, the baritone male tone is the most common of all male tones, according to the National Endowment for the Arts. In comedy, a baritone male often plays the most jovial of the characters, while in tragedy, he often plays the villain. Bass tones make up the lowest of the male vocal tones, and these characters are incredibly wise or evil in serious roles or buffoonish in comedic roles.
Bass-baritone vocal tones mix the depth and darkness of bass, with the ability to hit some of the higher notes that creep into the baritone range.