History (Antecedents: mid-1960s)

While heavy metal's quintessential guitar style, built around distortion-heavy riffs and power chords, traces its roots to the late 1950s instrumentals of American Link Wray, the genre's direct lineage begins in the mid-1960s. American blues music was a major influence on the early British rockers of the era. Bands like The Rolling Stones and The Yardbirds developed blues-rock by recording covers of many classic blues songs, often speeding up the tempos. As they experimented with the music, the UK blues-based bands—and the U.S. acts they influenced in turn—developed what would become the hallmarks of heavy metal, in particular, the loud, distorted guitar sound. The Kinks played a major role in popularizing this sound with their 1964 hits "You Really Got Me" and "All Day And All Of The Night." A significant contributor to the emerging guitar sound was the feedback facilitated by the new generation of amplifiers.

In addition to The Kinks' Dave Davies, other guitarists such as The Who's Pete Townshend and the Tridents' Jeff Beck were experimenting with feedback. Where the blues-rock drumming style started out largely as simple shuffle beats on small kits, drummers began using a more muscular, complex, and amplified approach to match and be heard against the increasingly loud guitar. Vocalists similarly modified their technique and increased their reliance on amplification, often becoming more stylized and dramatic. In terms of sheer volume, especially in live performance, The Who's "bigger-louder-wall-of-Marshalls" approach was seminal. Simultaneous advances in amplification and recording technology made it possible to successfully capture the power of this heavier approach on record.

The combination of blues-rock with psychedelic rock formed much of the original basis for heavy metal. One of the most influential bands in forging the merger of genres was the British power trio Cream, who derived a massive, heavy sound from unison riffing between guitarist Eric Clapton and bassist Jack Bruce, as well as Ginger Baker's double bass drumming. Their first two LPs, Fresh Cream (1966) and Disraeli Gears (1967), are regarded as essential prototypes for the future style. The Jimi Hendrix Experience's debut album, Are You Experienced (1967), was also highly influential. Hendrix's virtuosic technique would be emulated by many metal guitarists and the album's most successful single, "Purple Haze," is identified by some as the first heavy metal hit. Vanilla Fudge, whose first album also came out in 1967, have been called "one of the few American links between psychedelia and what soon became heavy metal."