The music of New Monsoon might evoke everything from world music to jazz, but, according to lead guitarist Jeff Miller, at its heart is good old rock ’n’ roll.

The popular Bay Area-based quintet will headline Helena’s newest music festival, Jammin’ the Gulch, a daylong event to be held in Kindrick Legion Field Saturday, Aug. 9. Along with New Monsoon, the lineup includes appearances by fellow Bay Area band Ten Mile Tide and regional favorites the Clumsy Lovers, and the Clintons.

When they returned to California in the late 1990s and decided to put together a band, Penn State classmates Miller, Bo Carper and Phil Ferlino didn’t know that their unique synthesis would strike such a chord with audiences, but it did.

Featuring tight vocal harmonies and mellow rock riffs, New Monsoon’s psychedelic sound is often compared to the Allman Brothers’ with a nod to rock greats like Santana and Jimi Hendrix.

“Everyone in the band has a very wide range of styles and influences,” says Miller. “I was raised on the good old rock ’n’ roll of the ’60s and ’70s.”

Even so, the band’s sound is still all its own. As a fan once told Miller, “No matter what style you guys are playing, it always sounds like New Monsoon.”

After making a decision to tour full time in 2003, the band has performed several times at the Fillmore in its hometown of San Francisco as well as major music festivals such as High Sierra and Bonnaroo.

In recent years, a few lineup changes have put the emphasis more on vocals and harmonies rather than world rhythms. With the addition of Sean Hutchinson on drums and Marshall Harrell on bass, Miller says that the group has been able to hone what it does best.

“I think the sound now is more streamlined and more focused,” Miller says.

Over the years, Miller says that he, Carper and Ferlino have become like brothers. And although some of the novelty of touring has worn off, it’s still incredibly gratifying to have the kind of fans who will fly across the country just to see you perform.

Because of New Monsoon, Miller says, “I’ve been able to experience so many of my dreams.”

“It’s a long, strange trip,” he said.

Helena Brewers assistant general manager Nick Bowsher says the Jammin’ the Gulch music festival is an attempt to bring some great entertainment to one of Helena’s only large venues.

“We’ve got this giant baseball field that isn’t used every day,” says Bowsher, who has been toying with the idea of a music festival for a few years.

New Monsoon is a band that Bowsher heard a few years ago that he thought would appeal to Helena audiences.

“I was pretty excited that the opportunity was there to bring ’em out here,” says Bowsher. “If people like the Clintons and the Clumsy Lovers, they’re really really gonna like New Monsoon.”

Bowsher says that for the concert, the stage will be on the field, with Mount Helena as the backdrop. Attendees will be able to set up blankets and chairs on the grass, and vendors will sell concessions throughout the day and into the night.

Bowsher says the decision to make Jammin’ the Gulch an annual occurrence will depend on the success of this inaugural event.

“I’d really like to do it again next year,” Bowsher said.