Drum kit in the context of "Chord chart"

A musical ensemble, also known as a music group, musical group, or a band is a group of people who perform instrumental and/or vocal music, with the ensemble typically known by a distinct name. Some music ensembles consist solely of instrumentalists, such as the jazz quartet or the orchestra. Other music ensembles consist solely of singers, such as choirs and doo-wop groups. In both popular music and classical music, there are ensembles in which both instrumentalists and singers perform, such as the rock band or the Baroque chamber group for basso continuo (harpsichord and cello) and one or more singers. In classical music, trios or quartets either blend the sounds of musical instrument families (such as piano, strings, and wind instruments) or group instruments from the same instrument family, such as string ensembles (e.g., string quartet) or wind ensembles (e.g., wind quintet). Some ensembles blend the sounds of a variety of instrument families, such as the orchestra, which uses a string section, brass instruments, woodwinds, and percussion instruments, or the concert band, which uses brass, woodwinds, and percussion. In jazz ensembles or combos, the instruments typically include wind instruments (one or more saxophones, trumpets, etc.), one or two chordal "comping" instruments (electric guitar, acoustic guitar, piano, or Hammond organ), a bass instrument (bass guitar or double bass), and a drummer or percussionist. Jazz ensembles may be solely instrumental, or they may consist of a group of instruments accompanying one or more singers. In rock and pop ensembles, usually called rock bands or pop bands, there are usually guitars and keyboards (piano, electric piano, Hammond organ, synthesizer, etc.), one or more singers, and a rhythm section made up of a bass guitar and drum kit.

Music ensembles typically have a leader. In jazz bands, rock and pop groups, and similar ensembles, this is the band leader. In classical music, orchestras, concert bands, and choirs are led by a conductor. In orchestra, the concertmaster (principal first violin player) is the instrumentalist leader of the orchestra. In orchestras, the individual sections also have leaders, typically called the "principal" of the section (e.g., the leader of the viola section is called the "principal viola"). Conductors are also used in jazz big bands and in some very large rock or pop ensembles (e.g., a rock concert that includes a string section, a horn section, and a choir that accompanies a rock band's performance).

The drum is a member of the percussion group of musical instruments. In the Hornbostel–Sachs classification system, it is a membranophone. Drums consist of at least one membrane, called a drumhead or drum skin, that is stretched over a shell and struck, either directly with the player's hands, or with a percussion mallet, to produce sound. There is usually a resonant head on the underside of the drum. Other techniques have been used to cause drums to make sound, such as the thumb roll. Drums are the world's oldest and most ubiquitous musical instruments, and the basic design has remained virtually unchanged for thousands of years.

Drums may be played individually, with the player using a single drum, and some drums such as the djembe are almost always played in this way. Others are normally played in a set of two or more, all played by one player, such as bongo drums and timpani. A number of different drums together with cymbals form the basic modern drum kit. Many drums are played together with other instruments.

Rock music is a genre of popular music that originated in the United States as "rock and roll" in the late 1940s and early 1950s, developing into a range of styles from the mid-1960s, primarily in the United States and United Kingdom. It has its roots in rock and roll, a style that drew from the black musical genres of blues and rhythm and blues, as well as from country music. Rock also drew strongly from genres such as electric blues and folk, and incorporated influences from jazz and other styles. Rock is typically centered on the electric guitar, usually as part of a rock group with electric bass guitar, drums, and one or more singers.

Usually, rock is song-based music with a
₄ time signature and using a verse–chorus form; however, the genre has become extremely diverse. Like pop music, lyrics often stress romantic love but also address a wide variety of other themes that are frequently social or political. Rock was the most popular genre of music in the U.S. and much of the western world from the 1960s up to the 2010s.

Funk is a music genre that originated in African-American communities in the mid-1960s when musicians created a rhythmic, danceable new form of music through a mixture of various music genres that were popular among African-Americans in the mid-20th century. It deemphasizes melody and chord progressions and focuses on a strong rhythmic groove of a bassline played by an electric bassist and a drum part played by a percussionist, often at slower tempos than other popular music. Funk typically consists of a complex percussive groove with rhythm instruments playing interlocking grooves that create a "hypnotic" and "danceable" feel. Early funk, specifically James Brown, fused jazz and blues, and added a syncopated drum groove.

Funk originated in the mid-1960s, with James Brown's development of a signature groove that emphasized the downbeat—with a heavy emphasis on the first beat of every measure ("The One"), and the application of swung 16th notes and syncopation on all basslines, drum patterns, and guitar riffs. Rock- and psychedelia-influenced musicians Sly and the Family Stone and Parliament-Funkadelic fostered more eclectic examples of the genre beginning in the late 1960s. Other musical groups developed Brown's innovations during the 1970s and the 1980s, including Kool and the Gang, Ohio Players, Fatback Band, Jimmy Castor Bunch, Bootsy Collins, Earth, Wind & Fire, B.T. Express, Hamilton Bohannon, One Way, Lakeside, Dazz Band, The Gap Band, Slave, Aurra, Roger Troutman & Zapp, Con Funk Shun, Cameo, Bar-Kays and Chic.

Bebop or bop is a style of jazz developed in the early to mid-1940s in the United States. It is characterized by a fast tempo, complex chord progressions—with rapid chord changes, changes of key, and substitute chords—along with virtuosic improvisation based on a combination of harmonic structure, scales, and occasional references to the melody.

Bebop developed as the younger generation of jazz musicians expanded the creative possibilities of jazz beyond the popular, dance-oriented swing music-style to a new "musician's music" that was not as danceable and demanded close listening. As bebop was not intended for dancing, it enabled the musicians to play at faster tempos. Bebop musicians explored advanced harmonies, complex syncopation, altered chords, extended chords, chord substitutions, asymmetrical phrasing, and intricate melodies. Bebop groups used rhythm sections in a way that expanded their role. Whereas the key ensemble of the swing music era was the big band of 16–18 musicians playing in an ensemble-based style, the classic bebop group was a small combo that consisted of saxophone (alto or tenor), trumpet, piano, guitar, double bass, and drums playing music in which the ensemble played a supportive role for soloists. Rather than play heavily arranged music, bebop musicians typically played the melody of a composition (called the "head") with the accompaniment of the rhythm section, followed by a section in which each of the performers improvised a solo, then returned to the melody at the end of the composition.

A session musician (also known as studio musician or backing musician) is a musician hired to perform in a recording session or a live performance. The term sideman is also used in the case of live performances, such as accompanying a recording artist on a tour. Session musicians are usually not permanent or official members of a musical ensemble or band.

Many session musicians specialize in playing common rhythm section instruments such as guitar, piano, bass, or drums. Others are specialists, and play brass, woodwinds, and strings. Many session musicians play multiple instruments, which lets them play in a wider range of musical situations, genres, and styles. Examples of "doubling" include double bass and electric bass, acoustic guitar and mandolin, piano and accordion, and saxophone and other woodwind instruments.

A rhythm section is a group of musicians within a music ensemble or band that provides the underlying rhythm, harmony and pulse of the accompaniment, providing a rhythmic and harmonic reference and "beat" for the rest of the band.The rhythm section is often contrasted with the roles of other musicians in the band, such as the lead guitarist or lead vocals whose primary job is to carry the melody.

The core elements of the rhythm section are usually the drum kit and bass. The drums and bass provide the basic pulse and groove of a song.The section is augmented by other instruments such as keyboard instruments and guitars that are used to play the chord progression upon which the song is based.The bass instrument (either double bass, or electric bass guitar, or another low-register instrument such as the synth bass, depending on the group and its style of music) plays the low-pitched bassline. The bassline is a musical part that supports the chord progression, typically by playing a musically interesting bassline that outlines the important notes of the harmony, often by emphasizing the root, fifth, and third of each chord.