NEW YORK — James Brown was Soul Brother No. 1 and, for a while, Marva Whitney was Soul Sister No. 1.
That was the nickname Brown gave her when she was a singer in the James Brown Revue and a solo artist on his King Records, turning out brassy, rowdy empowerment anthems that came to be prized by funk savants, sample-chasing hip-hop producers, and collectors.
As part of the James Brown Revue, Ms. Whitney, who died Dec. 22 at 68, had her own featured segment during its shows and sang duets with Brown, her vocals effortlessly intense. After joining the revue in 1967, she was with Brown in some of his most momentous shows during a tumultuous 1968, including performances in Vietnam for US soldiers and in Boston the night after the assassination of the Rev. Martin Luther King Jr.
Her breakthrough solo single was the urgent shout ‘‘Unwind Yourself,’’ which gained new life as the sample behind the seminal hip-hop breakbeat record ‘‘The 900 Number’’ by DJ Mark the 45 King.
Ms. Whitney was popular enough to land on the cover of Jet magazine, but her fame waned after she left Brown’s camp in late 1969.