As James Brown told both his audiences and his impeccably well-drilled band members, it’s all about “the one.” That’s what the Godfather of Soul called the downbeat, the rhythmic building block whose importance became paramount as black musicians of the ‘50s and ‘60s pared down the sounds of soul, jazz, and R&B to the barest fundamentals of rhythm and groove. Along with Brown, the supremely funky likes of Sly & the Family Stone, The Meters, and George Clinton’s sprawling Parliament-Funkadelic family spent the ‘70s making people move with music whose momentum, exuberance, and sheer relentlessness were irresistible to anything with a pulse. In the process, they created a versatile vocabulary that D’Angelo, Galactic, and other latter-day funkateers are all too happy to expand and adapt to their own rubbery and rhythmic purposes.