Aretha Franklin’s 1971 stand at the Fillmore West was meant, by her and her longtime producer Jerry Wexler, as a coronation. She’d spent the better part of the previousfive years at the top of the charts, and she toured stadiums around the U.S., but Wexler and Franklin were curious how powerful her crossover potential actually was. Would she go over with crowds used to seeing the Grateful Dead or Janis Joplin or The Allman Brothers Band? It was a moment to test Franklin’s mettle on an away court, the musical version of a football team dominating so mightily that they decide to conquer baseball too. When it came time to book the band backing Franklin at the Fillmore, Wexler and Franklin needed one that could both rock and fit the bill for the tightest soul outfit running, especially sin...