Professional singers are often extensively trained, are highly skilled, and have a great sense of pitch and tone. They also rely on inherent singing abilities, such as a wide vocal range and nice vocal resonation. Singers are primarily self-employed and hired on a project basis, whether as consultants, performers, or judges in singing competitions. Singing is an art form in both public and private schools. Karaoke, for example, can be a fun hobby and a kind of casual entertainment.