Most young rock ‘n’ rollers turn down the volume as they age, dropping the three-chord punk schtick in their later years in favor of blues and singer-songwriter gigs, or maybe for a cover band or two.

But when members of Nashville’s Step Sisters got together in 2015 — most of them having crossed the 30-year-mark and the unofficial threshold of adulthood — it was for the purpose of effecting an abrupt collective U-turn and re-embracing the louder, more lethal sounds of their youth.

“We had all been in other bands,” says bassist Matt Johanson. “And we all wanted to do something heavier, because we had been playing in blues and blues-based projects. We figured that even though we’re veterans, we’re still young at heart.”

Two loosely-organized do-it-yourself recording sessions later — one of them taking place in the back room of a local brewery — and the freshly-dubbed four-piece Step Sisters had enough music first for a four-song local cassette release, and then for a proper five-song EP, “Thick,” available now on the Sisters’ Bandcamp page.

“Thick” showcases an outfit strongly influenced by Nirvana, and the heady, early days of Sup Pop Records. Frontman Clint Wilson sings in a ragged-yet-melodic howl, and the band churns through adhesively tuneful song structures with an intensity that bridges the fraught divide between frenetic punk-rock scrappiness and authoritative metalloid heft.

But there’s something else in the mix, too, a patina of modern alt-rock psychedelia overlaying the familiar grunge-punk core. Johanson admits that the Step Sisters have drawn very deliberately from a melange of modern influences, though the band’s core mission is still vested in more traditional metal and punk.

“We drawn on some modern stuff like Goner Records out of Memphis, and especially (garage rocker) Jay Reatard,” Johanson says. “And a lot of the West Coast psychedelic sound played a big part in who we are, stuff like Ty Segall, and Thee Oh Sees.

“I think our main influences, though, are the bands we heard in our younger days; those were the sounds we really wanted to recreate. Clint and I love Nirvana. Adam (Swafford, guitarist) is from the Led Zeppelin school of thought. And then there’s Black Sabbath. Sabbath, and heavy metal in general, is what got me into picking up an instrument in the first place.”

Johanson promises those influences will figure even more prominently on the band’s next release. Between touring jaunts around the Southeast, he says the Sisters managed to log some heavy studio time in February, laying 12 new tracks for a yet-untitled new album, tentatively slated for release at the beginning of summer.

“The new record will be us really laying into some heavy, psychedelic songs,” Johanson says. “There’s not a lot of let-up there. It’s pretty heavy, and it’s fast. We’ve got a new tag line for the release of this one — ‘You can breathe when the record’s done.'”

The Step Sisters will play Scruffy City Hall Friday, March 24 at 11:30 p.m. as part of the Funny Ears Fringe Festival.