Singing is the act of producing musical sounds with the voice. A person who sings is called a singer or vocalist (in jazz and popular music). Singers perform music (arias, recitatives, songs, etc.) that can be sung with or without accompaniment by musical instruments. Singing is often done in an ensemble of musicians, such as a choir of singers or a band of instrumentalists. Singers may perform as soloists or accompanied by anything from a single instrument (as in art song or some jazz styles) up to a symphony orchestra. Singing classes help to encourage voice control and projection. As with dance, warm up is essential, and learning the correct technical skills to enhance the individual voice, brings out the best in the singer, whether aiming to be an opera singer or a rock chick.