Hard rock (also referred to as heavy rock) is a variation of rock music which has its earliest roots in mid-1960s garage and psychedelic rock. It is typified by a heavy use of distorted electric guitars, bass guitar, keyboards and drums. Today the term "hard rock" is often used as an umbrella term for genres such as alternative rock, grunge, heavy metal and punk in order to distinguish them from pop rock or soft rock.

Characteristics

Hard rock is strongly influenced by blues music; the most frequently used scale in hard rock is the pentatonic, which is a typical blues scale. Unlike traditional rock and roll (which takes elements of the "old" blues), hard rock incorporates elements of "British blues", a style of blues played with more modern instruments such as electric guitars, drums, keyboards and electric bass. A notable departure from traditional blues forms is that hard rock is seldom restricted to the I, IV, and V chords prevalent in twelve or sixteen bar blues, but includes other chords, typically major chords rooted on tones of the minor scale.

The term "hard rock" is often applied to many styles of rock music, their only common feature being that they deviate from pop rock, though this is generally incorrect. Two such examples are punk rock and grunge. Punk rock uses a faster tempo, less melody, fewer riffs (often using power chords), more aggression and anti-establishment lyrics.

Instrumentation

The predominant instruments in hard rock are the electric guitar, bass guitar, and drums. The role of the guitarist is very prevalent in hard rock. Most hard rock bands comprise two different types of guitarist: lead guitarist and rhythm guitarist. The lead guitarist plays the solos, riffs and fills. Speed-enhancing techniques such as alternate picking, sweep picking and tapping, are used by hard rock lead guitarists to maximize the speed of their solos and riffs. The role of the rhythm guitarist is to complement the lead guitarist and provide rhythmic and harmonic accompaniment to the other instruments in the band. The bass guitarist and drummer's role are important to the structure of hard rock music; the bassline outlines the melody of the music while the drums sustain the rhythm of the music.

Beginnings (1960s)

As stated, one of the major influences of hard rock is blues music, especially British blues. British rock bands, such as Cream, The Rolling Stones, The Yardbirds, The Who and The Kinks modified rock and roll, adding to the standard genre harder sounds, heavier guitar riffs, bombastic drumming and louder vocals. This sound created the basis for hard rock. Early forms of hard rock can be heard in the songs "You Really Got Me" by The Kinks, "Happenings Ten Years Time Ago" by The Yardbirds, "My Generation" and "I Can See for Miles" by The Who, and "Revolution" and "Helter Skelter" by The Beatles.