With a kind of exuberance bordering on obnoxiousness, too many white bluesmen have attempted to make up for their discomfort playing a form of black folk music that prizes authenticity. But Soledad Brothers’ singer-guitarist Johnny Walker often sounds as if he’s laying back and letting his favorite records speak through him from the Delta. On The Hardest Walk, his Detroit quartet’s fourth studio album, Walker admits some more contemporary influences and flashes some fluid guitar work that is bounds ahead of past brittleness but still retains his vocal humility. “Good Feeling” is one of the most immediately catchy tunes Walker has recorded, with a bright, overall Stonesy feel. And “Free and Easy” has got to be one of the top five T. Rex rips ever, deftly balancing Tin Pan Alley charm and high-octane groove. All told, The Hardest Walk is a richly produced tribute to the bluesy rock of the late ’60s and early ’70s. And though he hams it up a little with an intermittent drawl that may not be his own, Walker remains a white bluesman uncommonly comfortable in his skin.