Jazz and blues merged in the '00s, '10s, '20s, and '30s. The guy on the left in the hat is acoustic bluesman Robert Johnson, whom very few rhythm and blues artists were interested in as of the late '40s because none of his records had ever sold more than about 5000 copies to anyone, black or not, and the acoustic guitar had gone out of fashion in black music quickly back in about 1942. Johnson's famous because of dumb mythology invented by white people during the '70s and '80s to sell books and a movie to white people. The first black disc jockey was the guy in the photo, Jack Cooper, but he was on a Chicago station before the '40s, not on a Memphis station in the '40s. Rock and roll's initial popularity was on shellac, not vinyl.
Jazz and blues merged in the '00s, '10s, '20s, and '30s. The guy on the left in the hat is acoustic bluesman Robert Johnson, whom very few rhythm and blues artists were interested in as of the late '40s because none of his records had ever sold more than about 5000 copies to anyone, black or not, and the acoustic guitar had gone out of fashion in black music quickly back in about 1942. Johnson's famous because of dumb mythology invented by white people during the '70s and '80s to sell books and a movie to white people. The first black disc jockey was the guy in the photo, Jack Cooper, but he was on a Chicago station before the '40s, not on a Memphis station in the '40s. Rock and roll's initial popularity was on shellac, not vinyl.