I grew up in Cincinnati and saw these bands back when I was in high school (the Raisins, Ricky Nye's various groups, etc). Cincinnati always had a great mixed race R&B scene - it sits right on the Mason/Dixon line, and was a draw for both hillbillies and black folks to try their hand at King Records. Used to go to bars and see bands like Big Ed Thompson and the All Stars and H-Bomb Ferguson belting out this kind of music all the time.
Last time I visited Cincinnati I found this plaque for H-Bomb...