Passaggio is a term used in classical singing to describe the transition area between the vocal registers. The passaggi (plural) of the voice lie between the different vocal registers, such as the chest voice, where any singer can produce a powerful sound, the middle voice, and the head voice, where a powerful and resonant sound is accessible, but usually only through vocal training. The historic Italian school of singing describes a primo passaggio and a secondo passaggio connected through a zona di passaggio in the male voice and the a primo passaggio and secondo passaggio in the female voice. A major goal of classical voice training in classical styles is to maintain an even timbre throughout the passaggio. Through proper training, it is possible to produce a resonant and powerful sound.