Now, what that really means is a matter of debate - with such a depth and breadth of music at the Texas capitol, an "Austin sound" is particularly difficult to pinpoint.
But there is a common denominator that defines the phrase: authenticity. In other words, a band that composes for the sake of the song might well "sound like Austin."
The Gourds do - that's a fact. And their rabid, rambunctious fans flock accordingly. Tonight's capacity crowd of about 450 gathers in the beer garden at Threadgill's World Headquarters to celebrate the July 10 release of "Noble Creatures," the band's 10th studio effort and arguably finest moment to date.
Taking the stage, mandolin virtuoso Max Johnston jokes that their set is a late addition to Live Earth, this afternoon's global environmental lovefest which featured performances by the Police, Madonna and Akon.
"Yeah, we all walked here to save on energy," quips Kevin Russell, the band's cerebral songwriting force.
As expected, newer material dominates the nearly three-hour fiesta. Russell offers elegant turns on "Steeple Full of Swallows" and the anthemic "How Will You Shine," while bassist Jimmy Smith, the band's other primary songwriter, sends up the riotous new "Kicks in the Sun" and "A Few Extra Kilos."
"I don't like to toot my own horn," Smith says, clearly joking while introducing the latter, "but, damn - that's good!"
It certainly was. On the other hand, "How Will You Shine" - jubilant and AAA radio-ready on "Noble Creatures" - loses some of its thrust this evening. The reason: no horns. On the album, a boisterous brass section lifts the tune to inspired heights, but without that boost it's less successful.
As the celebration moves into its third hour, a seismic shift in the band's approach is undeniable. An enthusiastic fan named Mike, who drove down from Dallas specifically for the occasion, puts it best: "They used to do the Alison Krauss presentation - you know, the four-minute song - but now they just jam forever. I love it."
Others clearly agree. Long instrumental intros - most often, Russell complementing Johnston's fiery mando with his own electric guitar noodling - led into "Declineometer," the gritty new "Dr. Spivey" and a fist-pumping take on Cheap Trick's "Dream Police," garnering uproarious approval from the crowd.
It was another cover, though, that provides the most stunning and transcendent moment under this moon: a dirgy turn on, of all things, the Velvet Underground's "Sweet Nothing." Forget The Gourds' heavy metal bluegrass version of "Gin and Juice." Sure, it's been good for plenty of kicks over the past few years, but this is the real encore keeper. "Sweet Nothing" builds to such a rumbling crescendo that cheers might echo down Riverside Drive for months. Time will tell.