If you think an all-acoustic band with Boulder roots means a mellow, folksy sound, you haven’t heard the Yawpers. After forming in the People’s Republic in 2011, the rockin’ Americana trio quickly earned a rep for blistering live shows—they boast of being “equal parts frenetic, earnest, and menacing”—and opened for acts with similar styles, including the Dallas-based Reverend Horton Heat. After a 2011 EP, the Yawpers released an independent album in 2012 and finished another, American Man, in 2014. “It’s a pretty drastic departure from what we’ve done before,” says singer-guitarist Nate Cook. (Jesse Parmet plays guitar for the band, now based in Denver, and Noah Shomberg drums.) “We wanted to make something that sounded like our live shows and captured a tone that’s meaner, more aggressive, and vociferous.”

But the Yawpers, whose name pays respect to a Walt Whitman line, sat on American Man, believing the album—which Cook calls “Exile on Main Street on meth,” a reference to the classic 1972 Rolling Stones blues-rock record—deserved a major-label release. The Yawpers found such a backer this past March, when their attention-grabbing performances at the South By Southwest music festival in Austin ignited a brief but intense bidding war between several record labels. “By their third song I was giddily texting people, saying they had to see them,” says Rob Miller, who co-owns Chicago-based Bloodshot Records, which launched Ryan Adams, the Old 97’s, and Neko Case.

Pictured: The Yawpers’ new album, American Man, promises a mean spirit.

Bloodshot signed the Yawpers by agreeing to accept American Man as-is. The label will drop the album on October 30 before the band embarks on a two-month American tour. (A Denver release party performance is scheduled for November 21 at the Hi-Dive.) Whatever the group’s sonic inspirations, the Yawpers have found that sweet spot between sounding like other successful acts and still emitting, as Whitman would say, their own barbaric yawp.