Two years ago, Underworld duo Karl Hyde and Rick Smith had an epiphany. After more than three decades of working together — through some unremittingly lean early years; an epoch-defining, mega-selling turn in the 1990s; soundtracking the London Olympics opening ceremony, and a fractured and increasingly separate recent past — the pair suddenly realized a convenient truth. In touring their groundbreaking 1994 album "Dubnobasswithmyheadman," a record that shifted the parameters of what was possible in dance music, the two men figured out that not only did they appreciate each other, they also liked each other.