MUSICAL ELEMENTS  
The central musical instrument in most kinds of rock music is the electric guitar. Important figures in the history of this instrument include jazz musician Charlie Christian, who in the late 1930s was one of the first to perform the amplified guitar as a solo instrument; Aaron Thibeaux “T-Bone” Walker, the first blues musician to record with an amplified guitar (1942); Leo Fender, who in 1948 introduced the first mass-produced solid-body electric guitar; and Les Paul, who popularized the instrument in the early 1950s with a series of technologically innovative recordings. Rock-and-roll guitarist Chuck Berry established a style of playing in the late 1950s that remains a great influence on rock music. Beginning in the late 1960s a new generation of rock guitarists, including Jimi Hendrix, Eric Clapton, and Carlos Santana, experimented with amplification, feedback (a type of electronic sound distortion), and various electronic devices, extending the musical potential of the instrument.

Other instruments commonly used in rock music include the electric bass guitar (introduced by Fender in 1951); keyboard instruments such as the electric piano, organ, and synthesizer; and the drum set, an African American innovation that came into rock music from jazz and R&B music. Instruments that play important roles in certain rock-music genres include the saxophone—prominent in jazz-rock and soul music—and a wide assortment of traditional instruments used in worldbeat music. The microphone also functions as a musical instrument for many rock singers, who rely upon the amplification and various effects (such as echo) obtainable through electronic means.

Rock music also shares more complex technical aspects. Most rock music is based on the same harmonies as Western music, especially the chords known as tonic, subdominant, and dominant (see Harmony: Functional Chord Names). The chord progression (series of chords) known as the 12-bar blues is based on these chords and has figured prominently in certain styles, especially rock and roll, soul music, and southern rock. Other common harmonic devices include the use of a drone, or pedal point (a single pitch sustained through a progression of chords), and the parallel movement of chords, derived from a technique on the electric guitar known as bar-chording. Many elements of African American music have been a continuing source of influence on rock music. These characteristics include riffs (repeated patterns), backbeats (emphasizing the second and fourth beats of each measure; see Musical Rhythm: Pulse and Meter), call-and-reponse patterns, blue notes (the use of certain bent-sounding pitches, especially those related to the third and fifth degrees of a musical scale), and dense buzzy-sounding timbres, or tone colors.

The musical form of rock music varies. Rock and roll of the late 1950s relied heavily upon 12-bar blues and 32-bar song forms. Some rock bands of the late 1960s experimented with more flexible, open-ended forms, and some rock bands of the 1970s developed suite forms derived from classical music. Another important formal development in rock music has been the so-called concept album, a succession of musical pieces tied together by a loose narrative theme.

Much rock music is performed at high volume levels, so the music has been closely tied to developments in electronic technology. Rock musicians have pioneered new studio recording techniques, such as multi-tracking—a process of recording different song segments at different times and layering them on top of one another—and digital sampling, the reproduction by a computer of the patterns of a particular sound. Rock concerts, typically huge events involving thousands of audience members, often feature high-tech theatrical stage effects, including synchronized lighting.