 ), students aiming for a career as professional musicians take a music lesson once a week for an hour or more with a music professor over a period of years to learn advanced playing or singing techniques.Many instrumental performers and singers, including a number of pop music celebrities, have learned music "by ear", especially in folk music styles such as blues and popular styles such as rock music.Nevertheless, even in folk and popular styles, a number of performers have had some type of music lessons, such as meeting with a vocal coach or getting childhood instruction in an instrument such as piano.