Hip hop soul is a subgenre of contemporary R&B music, most popular during the early and mid 1990s, which fuses rhythm and blues/gospel singing with hip hop musical production. The subgenre had evolved from a previous R&B subgenre, new jack swing, which had incorporated hip-hop influences into R&B music. By contrast, hip hop soul is, as described in The Encyclopedia of African American Music, “quite literally soul singing over hip hop grooves”. ~courtesy of wikipedia~
This style of R&B beats has its roots in late 80s and early 90s eras of R&B. From The way producer Teddy Riley incorporated Hip Hop grooves into his productions for artists like Guy and Keith Sweat to the soulful Hip Hop jams of a Mary J Blige or Jodeci Hip Hop Soul pretty much defined a lot of what we knew as R&B in the 90s. These instrumental beats mold together the melodies of traditional R&B with the boom bap and break beats of East coast Hip Hop.