It is an underlying truth of the music biz that when a band or artist steps into the studio, they’re musicians; but when they step on stage, they’re performers—a totally different skill-set and dynamic. Though as is evidenced by the genre of shoegaze, not every band embraces that principle.

But one that does—and in a really big way—is Portland ensemble March Fourth Marching Band, who will be taking over the Historic Ashland Armory for a sight and sound sensation on Thursday, Dec. 17.

More than just a collection of instrumentalists playing in tandem, March Fourth is a full-body experience with a rotating cast of dozens of musicians playing loud brassy marches and Sousafied reboots of pop music styles, while a circus rages on and off-stage. Stilt-walkers perfect complex acrobatic moves, as dancers perform on strings as marionettes and hula-hoopers whirl. All of them are dressed in Steampunk-influenced marching band regalia that would be right at home in the LSD Mardi Gras scene from Easy Rider. Rarely content to keep to the stage, the band typically takes its show to the dance floor as well with the musicians and performers co-mingling with revelers as one ecstatic throng.

“When you come to a MarchFourth show, we don’t want you to feel like you’re just sitting in your chair watching a performance,” Phill Stasz, stilt walker and dance team co-captain, told the Bend Source in February of this year. “We want you to feel like you’re part of a big, raucous, crazy, ass-shaking party full of glitter with stilt walkers and horns in your face.”

It’s a spectacle that has earned March Fourth Marching Band appearances at what the band describes as nearly every freak festival on Earth, including Bumbershoot, Tour de Fat, Burning Man and more.

“Subtlety isn’t really our strong suit,” said Stasz.

The band originally formed in 2003 for a Mardi Gras party in Portland’s Albert Street arts district. In true New Orleans fashion, a dozen years later, the party is still going.

But occasionally lost in that frenetic chaos is just how good the songs are. Though horn and drumline driven, the band’s sound goes far beyond the Dixieland brassband sound. The straight-four overdriven bass riff of “Leslie Metal,” cooks the song forward like a Judas Priest tune. “Soldiers of the Mind,” brings ska back from the penalty box its languished in since the mid-90s, and “Cowbell,” takes the one-note SNL-joke on a journey from funky dance tune to the headbangers ball, concluding with a magnificently heavy descending horn line in six. The band’s 2011 album Magnificent Beast stood out as one of the year’s best in a year that saw new releases from Radiohead, Adele and Mastodon.

But should you attend the band’s performance in Ashland, don’t feel bad if analyzing the sonic complexity gets lost in all the booty-shaking.

“When it’s all over you might not even know what was going on, but you’ll know you had a good time,” said Stasz.

March Fourth Marching Band, with Sugar Beats
9 pm, Thurs., Dec. 17
Historic Ashland Armory, 208 Oak St., Ashland
$20 adv., $25 door, 21 and older