Two members of the Nashville rabble-rousers The Legendary Shack Shakers created the idea for Agri-dustrial, their fifth studio album, well before they even existed.

Roughly a decade ago, Shack Shakers leader J.D. Wilkes and guitarist Duane Denison (formerly of alt-rock heroes Tomahawk and The Jesus Lizard) were neighbors playing music and trying out sounds.

“Me and him were messing around with what he calls ‘prepared guitar,'” Wilkes says. Running random bits of metal and mechanical components through and around his guitar strings, Denison was creating what Wilkes describes as “crunchy, rustic sound effects” against the traditional country music backdrop the duo used as its foundation.

“It was like Johnny Cash putting a dollar bill through his strings,” says Wilkes.

Eventually, the two moved on. Wilkes started and led his Shack Shakers through four LPs (including stints on notable indie labels Bloodshot and Yep Roc), honing the band’s manic, Southern Gothic spin on blues, rockabilly, country, and punk cast through the lens of a twisted, backwoods vaudevillian. They built a reputation not only for their flash-fried punk parables, but also for a physical, unforgettable stage show that often finds Wilkes prowling the stage like a possessed contortionist, exorcizing his lyrics as much as singing them.

But at the end of their run with Yep Roc, following 2007’s Swampblood, it was time for a change. Wilkes, who says he’s been saving the “Agri-dustrial” concept over the years since he first jammed with Denison, decided it was time to resurrect the idea that had been nagging him for so many years.

“It does seem like there’s been a bit of a sea change,” says Denison.

Wilkes elaborates. “We went from something that was quite theatric to something cinematic.”

He says the band is now playing in peak form. “Even if it didn’t have a wild frontman, I’d like to see this band,” Wilkes says. “Everyone in the band can play what they’re thinking in the moment.”

That musical assuredness permeates Agri-dustrial. There’s a feeling of relaxed confidence in the call-and-response the bandmates share. The rhythm section of bassist Mark Robertson and drummer Brett Whitacre is tighter and more volatile than it’s ever been. Denison, who replaced guitarist David Lee in the summer of 2008, says he fills a vital role as a foil to Wilkes (like he does to The Jesus Lizard’s notoriously charismatic David Yow). “He’s the main man, and I’m the side man. That’s not a role I mind,” he says. It allows him, after all, to focus less on the style and flash and more on “rhythmic propulsion” and “blasts of different colors.”

For his role in the Shack Shakers, Denison counts myriad influences, from western swing bandleaders to Django Reinhardt’s gypsy-jazz, from experimental guitarist Marc Ribot to X’s Billy Zoom. The slide guitar techniques he uses to color Agri-dustrial echo gritty blues and The Jesus Lizard in equal measure.

Even though he stands to the side of the stage, Denison’s contributions are as vital to defining the new sound of The Legendary Shack Shakers as the speedometer-pegging rhythm section or Wilkes’ howls. When Wilkes brings out his harmonica, the Shack Shakers seem to interact with an easy confidence, for brash timbres congealing and separating.

Indeed, the band sounds freer and better than it has to date.

“We have the talent now to fully realize the conceptual side of the band,” says Wilkes. “Getting it to sound the way I hear it in my head, or we hear it in our heads, is the big thing.”

As long as Wilkes is pinballing from the front of the stage, The Legendary Shack Shakers won’t be confused for any other band. Denison is correct when he reminds us that “it’s driven by the vocals and his harmonica.” But he’s correct, too, when he acknowledges this band is a changed band.

The pieces are in place; the musicianship is kicked up. And, says Denison, “The musicality is part of what makes it kick ass.”