Acid jazz is a musical genre that combines elements of jazz, funk and hip-hop, particularly looped beats. It developed in the UK over the 1980s and 1990s and could be seen as tacking the sound of jazz-funk onto electronic dance: jazz-funk musicians such as Roy Ayers, Donald Byrd and Grant Green are often credited as forerunners of acid jazz. Acid jazz has also experienced minor influences from soul, house, and disco.
While acid jazz often contains various types of electronic composition (sometimes including sampling or live DJ cutting and scratching), it is just as likely to be played live by musicians, who often showcase jazz interpretation as part of their performance. The compositions of groups such as Jamiroquai, Galliano, Urban Species, The Brand New Heavies, Los Amigos Invisibles and Incognito often feature chord structures usually associated with jazz music.
The acid jazz "movement" is also seen as a revival of jazz-funk or jazz fusion or soul jazz by leading DJs such as Norman Jay or Gilles Peterson or Patrick Forge, also known as "rare groove crate diggers" or "Cataroos".
Jazz-funk is a sub-genre of jazz music characterized by a strong back beat (groove), electrified sounds, and often, the presence of the first electronic analog synthesizers. The integration of funk, soul, and R&B music and styles into jazz resulted in the creation of a genre whose spectrum is indeed quite wide and ranges from strong jazz improvisation to soul, funk or disco with jazz arrangements, jazz riffs, and jazz solos, and sometimes soul vocals. Jazz-funk is primarily an American genre, where it was popular throughout the 1970s and the early 1980s, but it also achieved noted appeal on the club-circuit in England during the mid 1970s. Similar genres include soul jazz and jazz fusion, but neither entirely overlap with jazz-funk. Notably jazz-funk is less vocal, more arranged and featured more improv than soul jazz, and retains a strong feel of groove and R&B versus some of the jazz fusion production.
At the jazz end of the spectrum, jazz-funk characteristics include a departure from ternary rhythm (near-triplet), i.e. the "swing" (see swing rhythm), to the more danceable and unfamiliar binary rhythm, known as the "groove". It is therefore no surprise that this type of jazz saw its name associated with the term funk, a genre that created this groove rhythm, which was spearheaded by James Brown's drummers Clyde Stubblefield and John "Jabo" Starks. Jazz-funk also draws influences from traditional African music, Latin American rhythms, and Jamaican reggae. A second characteristic of jazz-funk music was the use of electric instruments, such as the Rhodes Piano or the electric bass guitar, particularly in jazz fusion (or electro-jazz), and the first use of analogue electronic instruments notably by Herbie Hancock, whose jazz-funk period saw him surrounded on stage or in the studio by several Moog synthesizers. The ARP Odyssey, ARP String Ensemble, and Hohner D6 Clavinet also became popular at the time. A third feature is the shift of proportions between composition and improvisation. Arrangements, melody, and overall writing were heavily emphasized.