Hard rock is a loosely defined subgenre of rock music that began in the mid-1960s, with the garage, psychedelic and blues rock movements. It is typified by a heavy use of aggressive vocals, distorted electric guitars, bass guitar, drums, and often accompanied with pianos and keyboards.

Heavy metal (or simply metal) is a genre of rock music that developed in the late 1960s and early 1970s, largely in the United Kingdom and the United States. With roots in blues rock and psychedelic rock, the bands that created heavy metal developed a thick, massive sound, characterized by highly amplified distortion, extended guitar solos, emphatic beats, and overall loudness. Heavy metal lyrics and performance styles are often associated with masculinity, aggression, and machismo.