With a darker, more velvety tone and timbre than the soprano voice, the mezzo-soprano is beloved by operatic composers seeking to evoke complex personalities. Mezzo roles often include women harboring dark secrets or seeking revenge, as well as passionate young men, in what are known as “trouser” (or travesti) roles. In oratorio and concert works, the mezzo voice adds warmth and texture to the traditional quartet, sitting below the soprano and above the tenor, baritone, and bass.