Blues music became popular with the African-American community in 1930, after its artists played for years in clubs they could gain access to only if they worked at the venue. Blues music takes its name from the use of "blue notes" (notes that are lowered half a step), which add a melancholy tone to musical phrases. The Free Dictionary defines the blues as "a type of folksong that originated among Black Americans at the beginning of the 20th century; has a melancholy sound from repeated use of blue notes." These folk songs spread out from Southern plantations, as unemployed cotton workers migrated from rural life to city life in places like Memphis, according to "A brief history of Blues Music," by Piero Scaruffi. The blues form was one of the earliest types of African-American music and it heavily influenced later music genres, including jazz, rock and roll, rap, soul and R&B. Famous blues singers include B.B. King, Jimmy Rushing, Billie Holiday and Bessie Smith.
African-American soul music "originated in black American gospel singing, is closely related to rhythm and blues, and is characterized by intensity of feeling and earthiness," according to the Merriam-Webster Dictionary. The genre was most popular between 1955 and 1970, when songs like Sam Cooke's "A Change Is Gonna Come" expressed the aspirations of the Civil Rights movement. African-American soul music artists of note include Aretha Franklin, Marvin Gaye and James Brown.
Rap music takes its name from the slang term meaning "speech" and is defined by the Columbia Encyclopedia as "rhyming lyrics chanted to a musical accompaniment." Rap emerged in the African-American neighborhoods of New York City in the 1970s, evolving from hip-hop and crystallizing into this popular type of African-American music by 1990. In a report for the Portland Public Schools Geocultural Baseline Essay Studies, John Lawrence-McIntyre observes, "Rapping music truly represents the African tradition in its use of the human voice as the ultimate instrument to produce the sound." Early rappers include Grandmaster Flash, The Furious Five, the Sugar Hill Gang and the Beastie Boys. Examples of later performers who established the genre in mainstream music are Eminem, Public Enemy and Jay Z.