Rock music, sometimes also known as "rock and roll" is a style of music that became popular in the 1950s in America and Europe. Rock music is primarily based on older musical styles, such as the rhythm and blues music originated by African American performers such as Chuck Berry and Little Richard, with a heavy focus on guitar, drums,and powerful vocals. A group of musicians specializing in rock music is called a rock band or rock group. Many rock groups consist of an electric guitarist, lead singer, bass guitarist, and a drummer, forming a quartet. Some groups omit one or more of these roles and/or utilize a lead singer who plays an instrument while singing, sometimes forming a trio or duo; others include additional musicians such as one or two rhythm guitarists and/or a keyboardist. More rarely, groups also utilize stringed instruments such as violins or cellos, woodwind instruments such as saxophones, and brass instruments such as trumpets or trombones.Today, the term "rock music" is used to refer to a wide range of musical forms, including anything from soft pop to heavy metal. Rock music has essentially become a default term for Any style of music that does not automatically fit into another category