Blues-rock is a hybrid musical genre combining bluesy improvisations over the 12-bar blues and extended boogie jams with Rock and roll styles. The core of the blues rock sound is created by the electric guitar, bass guitar and drum kit, with the electric guitar usually amplified through a tube guitar amplifier, giving it an overdriven character.
The style began to develop in the mid-1960s in England and the United States, as what one music critic called a "genre of rhythm'n'blues played by white European musicians". UK Bands such as The Animals, Cream and The Rolling Stones experimented with music from the older American bluesmen like Howlin' Wolf, Jimmy Reed and Muddy Waters.While the early blues-rock bands "attempted to play long, involved improvisations which were commonplace on jazz records", by the 1970s, blues rock got heavier and more riff-based. By the "early '70s, the lines between blues-rock and hard rock were barely visible", as bands began recording rock-style albums. In the 1980s and 1990s, blues-rock bands returned to their bluesy roots, and some of these bands, such as the "Fabulous Thunderbirds and Stevie Ray Vaughan flirted with rock stardom."
Blues-rock pieces normally follow the 12-bar blues structure, but often follow a slightly different structure, as seen in the Allman Brothers version of the T-Bone Walker song "Stormy Monday", which follows the general format of a 12-bar blues, but with altered chords, playing:
A classic example of blues-rock is Cream's "Crossroads" on "Wheels of Fire" album, adapted from Robert Johnson's "Cross Road Blues" and "Traveling Riverside Blues". It fuses some of the lyrical and musical styles of blues with rock-styled tempo and guitar solos.
Music critic Piero Scaruffi argues that the blues-rock genre was defined when John Mayall released the album Bluesbreakers in 1966, which included guitarist Eric Clapton. Scaruffi defines "blues-rock" as a "genre of rhythm'n'blues played by white European musicians." Scaruffi claims that the US "equivalent of John Mayall was Al Kooper." Cream "took the fusion of blues and rock to places where it had never been before" by engaging in a "level of group improvisation that was worthy of jazz." He calls Fleetwood Mac (during the Peter Green period in the late 1960s) "one of the most creative and competent British bands of the blues revival." blues. Scaruffi argues that the "British blues musicians were true innovators", in that they did a "metamorphosis" on US blues and "turned it into a "white" music" by emphasizing "the epic refrains of the call and response", speeding up the "Chicago's [(Chicago Blues)] rhythm guitars," smoothing "the vocal delivery to make it sound more operatic" and adding vocal harmony.
The revolutionary electric guitar playing of Jimi Hendrix (a veteran of many American rhythm & blues and soul groups from the early-mid 1960s) and his power trios, The Jimi Hendrix Experience and Band of Gypsys, has had broad and lasting influence on the development of blues-rock, especially for guitarists. Eric Clapton was another guitarist with a lasting influence on the genre; his work in the 1960s and 1970s with John Mayall and the Bluesbreakers, The Yardbirds, supergroups Blind Faith, Cream and Derek and the Dominos, and an extensive solo career has been seminal in bringing blues-rock into the mainstream.By this time, American acts such as The Doors and Janis Joplin further introduced mainstream audiences to the genre.
In the late '60s Jeff Beck a former member of The Yardbirds, revolutionised blues rock into a form of heavy rock, taking the UK and the USA by storm with his band, The Jeff Beck Group. Jimmy Page, a third alumnus of The Yardbirds, went out to form The New Yardbirds which would soon become known as Led Zeppelin. Led Zeppelin was a huge force in the early 70s blues-rock scene. The Australian band AC/DC were also influenced by blues rock. Other blues-rock musicians influential on the scene in the 1970s included Rory Gallagher and Robin Trower.
Beginning in the early 1970s, American bands such as Aerosmith fused blues and heavy metal similar to the way that Led Zeppelin had just a few years earlier. Blues-rock grew to include Southern rock and hard rock bands like the Allman Brothers Band, ZZ Top and Lynyrd Skynyrd while the British scene — except for the advent of groups such as Status Quo and Foghat became focused on heavy metal innovation. Blues-rock had a re-birth in the early 1990s, with many artists such as John Mayer, The Black Crowes, The Black Keys, The Jon Spencer Blues Explosion, Silvertide, and Joe Bonamassa.
For a longer list of blues rock groups and artists, see the List of blues-rock performers.