The inception of rock music has its roots in the combination of traditional music of black and white races in the Southern United States. Though it is debated as to whether rock music was a rebranding of traditionally African American music, such as rhythm and blues and country, to make it more palatable to white audiences, or whether rock and roll developed as a combination of white and black musical genres. The music considered to be the first rock music was produced in the 1940s, though the term "rock and roll" was not applied to the genre until rockabilly became popular in the 1950s.
Musical elements common to both soul and rock music include the uses of the 12-bar blues chord progression, backbeats and a blue note. The 12-bar blues chord progression relies on the use of tonic, subdominant and dominant chords for musical composition in both soul and rock music. The rythmic compnents of both rock and soul music rely heavily on use of a backbeat, or the emphasis of the second and fourth beats of each measure. Blue notes, named after and frequently used in the blues musical genre, bends the pitch of the third and fifth musical notes in a scale and is also commonly used in rock music.
Jazz music most directly influenced rock music with its instrumentation set-up. During World War II, formerly large jazz bands were forced to reduce in size, creating smaller combos with a guitarist, bassist and drummer. This set-up became the de facto set up for most early and contemporary rock bands. Additionally, the invention of the electric guitar, first used in jazz combos, allowed both the rock and jazz musician to experiment with guitar solos over the beat and rhythm of the drum and bass.
Historically, rock 'n roll music could not be performed without the technological inventions of the mid-20th century. In addition to the invention of the electric guitar, which transformed jazz combos into rock 'n roll acts, the invention and accessibility of the microphone also has a direct impact on elements of rock music. Since rock music was developing as these inventions were being made, amplified instrumentation, an emphasis on the lyrics of songs and music being performed at high volume levels are all commonly considered to be elemental in rock music.