 One style of rhythm and blues was mostly vocal, with instrumental backing that ranged from a full orchestra to none.It was most often performed by a group, frequently a quartet, as in the black gospel tradition; utilizing close harmonies, this style was nearly always performed in a slow to medium tempo.The lead voice, usually one in the upper register, often sang over the driving, wordless chords of the other singers or interacted with them in a call-and-response exchange.