Photograph: Jordan Young

The same week Wild Belle released its debut album, Isles, on Columbia Records, the Barrington siblings Natalie and Elliott Bergman headed to SXSW. There, the buzzy new reggae-meets-electronica-and-jazz band, held a label showcase and intimate day show at Austin’s Waterloo Records.

The band (now enhanced by a guitarist and drummer) held court in a sun-drenched parking lot, set against a backdrop of palm trees and local food trucks. The scene was much like the Hideout Block Party, where they killed it last September.

The brief 30-minute set perfected the band’s trademark of laidback calypso jams, including “Happy Home” and “Another Girl.” Singer Natalie’s Billie Holiday rasp was fleshed out by the addition of two new backup singers/dancers. Her bandmate Elliott’s tenor sax riffs were wildly applauded—a throwback to the horn-heavy afrobeat band Nomo he founded while in college. That was where Natalie first flexed her vocal chops.

In a crowded week of gimmicky promotions, crazy stage getups and secret show mania, Wild Belle beat the competition just by playing it cool.

Dressed in denim and sunglasses, and with little stage banter, the band let the music and its set-to-chill vibe just speak for itself. The scene was laid-back to the extreme. Swaying palm trees had more swagger than the listless crowd. Backpacked moms kept their kids distracted by Whole Foods snacks. And the autograph line had to be the most civil ever seen at a rock concert.

In fact, the “wildest” thing that happed during this set was the audience participation, as the crowd accompanied the vocals on the single “Keep You.” Later, as Natalie signed albums inside a record store, she said, “I was so shocked to see so many people singing along. That’s all we ever wanted.”

Selena Fragassi is a contributing music critic for Chicago.