Even the members of The Lumineers are puzzled by the success of their song “Ho Hey” and their sudden rise to fame after years on the road. The song has long legs and is not only getting played alongside Nicki Minaj and Maroon 5 on the radio, it’s been ruling Spotify and working its way into popular culture.

A few years ago, singer Wesley Schultz said, hearing The Lumineers’ brand of all-acoustic folk rock on a Top 40 countdown would have been pretty unthinkable. Now his band’s caught up in a wave that could crest at the Grammy Awards, and he says he’s still trying to sort out why.

“I can tell you that when we play live and when we sometimes go out in the audience, the reaction to just playing your instruments without any help, without any amplification or tricks, that surprises people in kind of a funny way because you’d think that most people would assume you could play your instruments and how it would sound,” Schultz said. “But they’re caught off guard, I think. People are used to things that are overproduced or slick or glossy, and this isn’t any of that.”