– One of the most pleasantly noisy bands at South by Southwest two weeks ago, the Joy Formidable somehow found a quiet downtown wine bar to relax and share a classy bottle of white before the last of its six gigs there.

“Six?! I thought it was five,” singer/guitarist Ritzy Bryan said to drummer Matt Thomas, her voice rising along with her regal-sounding Welsh accent. “Where the hell did the fifth one go, then?”

Bryan and her two male bandmates actually scaled back, compared with the nine sets they played at Austin’s mega-fest in 2011, when they arrived with modest buzz and left as a must-see act.

U.S. fans had plenty of chances to catch the Welsh trio’s fast-burning, bed-headed rock roar. The group spent a year and a half touring behind its debut album — a rigorous ride that splintered the romantic relationship at the center of the band but only seemed to reinforce its musical foundation. Hence the title of the group’s new album, “Wolf’s Law,” named after the scientific theory that bones grow stronger in response to stress.

Primed to return to the road right after that final SXSW showcase — no hotel that night — the Joy Formidable makes its First Avenue debut as a headliner Wednesday, almost exactly two years since its sold-out, full-tilt local debut next door in 7th Street Entry.

“Minneapolis is one of those lovely cities where we like to get out and see the birds and trees, if we can,” said Thomas, and he wasn’t kidding. The band members are nature lovers who expressed interest in Austin’s famous population of bats. (Not so coincidentally, one of their new songs is called “Bats.”)

Off-stage, Bryan is bubbly and thoughtful, yet a wee bit crude with her jokes. As when Thomas pointed out how tame the band’s road life can be by saying the most titillating part of his day was “having porridge on the bus this morning.”

“Yeah, but did you snort it again?” Ritzy cracked.

On stage, she is the unequivocal focal point, a burning ball of energy. With her bleached-blond hair and manic approach to her Fender Jaguar guitar, she resembles Kurt Cobain. And like Nirvana, this little band sounds way bigger than it looks.

They have a little unseen help. The band is using more pre-recorded loops to reflect the new album’s more ambitious sonic palette. That’s better than adding musicians and risking the trio’s obvious chemistry, bassist Rhydian Dafydd said.

“The dynamic between the three of us is so good, it doesn’t feel right to have someone else come in,” Dafydd said. “As long as what we’re playing live is the featured sound, having some loops and tracks is not a big deal. We make big efforts to still have a lot of freedom in the show, too.”

Friends first — and finally

The romantic connection in the group was between Dafydd and Bryan, childhood friends who played in a couple of bands before starting the Joy Formidable in 2007. Seated opposite each other during the SXSW interview, the exes talked openly about not wanting to be ex-bandmates.

“There’s a real solid friendship there, and there always was,” Dafydd said. “In a way, what happened has filtered everything down to what was most important in the first place, which was the music we create together.”

Said Bryan, “It’s funny: Some of the songs on the record feel like premonitions of the worst-case scenario, if our relationship ended. The anxiety of our relationship failing is on there.

“At the same time, it’s trying to celebrate our friendship, even more so now. The friendship and the songwriting partnership both involve a lot of deep respect, and that’s never faltered.”

“Let’s sit and talk and slow things down / Just be our old selves again finally,” she sings in “This Ladder Is Ours,” the new album’s Belly-like opening track, and probably its most accessible. Save for “Silent Treatment,” a lush acoustic song, “Wolf’s Law” is loaded with heavier, more bombastic material — yes, even more roaring than the first album, “The Big Roar” — including the Nirvana-esque throttler “Cholla” and the atmospheric screecher “Tendons.”

Even with all the strong new offerings, the Joy Formidable’s live showpiece remains its aptly named breakthrough single, “Whirring,”which gets stretched out and amped up on stage. It’s one of those spine-buzzing thrills that makes you wonder whether the trio is as fulfilled playing it night-to-night as audiences are in hearing it.

“Yes, absolutely,” Dafydd confirmed. “We keep that one spontaneous, for ourselves as much as everyone else.”

Said Bryan, “We come off the stage a lot of times feeling bemused by what went down in that song. We discover new things a lot of times in the release of that adrenaline.”

It’s as good for them as it is for us, in other words.