Tower of Power, the Bay Area bump-and-grind horn band that emerged in the early 1970s, was best known for their greasy, driving funk hits such as What Is Hip, Get Yo’ Feet Back on the Ground and Knock Yourself Out. But many of these started to sound formulaic by mid-decade. Fifty years later, the real Tower of Power gems are their ballads. [Photo above of Tower of Power in the early 1970s]