Blue songs work best on the street. The impassioned solo lines—performed one at a time, boy band style—and chest-beating R&B harmonies take flight from heavy (in both senses of the word) hip hop beats and tough funk, a synthesis created to highlight both the communal joy (“All Rise”, “One Love”) and toughness (“Walk Away”) of an urban landscape. Even their more languid ballads (“If You Come Back”, “Breathe Easy”) are turbocharged with fat bass and always delivered with more than a little city grit.