R&B first stream was in Los Angeles (late 1940s) and this genre came out of jazz. An electrical guitar was played and modernized the music to sound louder. Charlie Parker and Miles Davis were popular artists during this time.
This genre started the second stream; Rock and Roll (1950s). Little Richard, Chuck Berry, and Etta James were apart of Chess Records during this stream.
R&B had a third stream in the 1960s and included Soul. Aretha Franklin, Patti LaBelle, Luther Vandross, Anita Baker, and Gerald Levert were some popular artists during this stream.