Singing is the act of creating musical sounds with the voice. 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. Singers may perform as soloists or accompanied by anything from a single instrument (as in art songs or some jazz styles) up to a symphony orchestra or big band. Many styles of singing exist throughout the world. Singing can be formal or informal, arranged, or improvised. It may be done as a form of religious devotion, as a hobby, as a source of pleasure, comfort, as part of a ritual, during music education or as a profession. Excellence in singing requires time, dedication, instruction, and regular practice. If practice is done regularly then the sounds can become clearer and stronger.