One of the oddities of life in Music City is that it’s possible to be part of a supergroup even if the rest of the world doesn’t know your name, which is pretty much the case with the SteelDrivers. If you know what the Station Inn is and who made it famous, you might recognize a few of the acoustic quintet’s members, but beyond that they’re unknowns.

Unknowns, that is, with three Grammy nominations and a handful of hit songs to their credit. The thing about singer-guitarist Gary Nichols, fiddler Tammy Rogers, banjo player Richard Bailey, mandolinist Brent Truitt, and bassist Mike Fleming is that they’re all respected contributors to life in the capital of country music, but most of the time they’re playing on other people’s records. And when they do get on-stage—with Dolly Parton, the Dixie Chicks, and Alison Krauss, among others—they’re usually off to the side, sounding magnificent but staying out of the spotlight.

So playing as the SteelDrivers is their chance to shine, and that’s exactly what they do on 2013’s Hammer Down, their third full-length release. At heart it’s a bluegrass record—but it’s honky-tonk bluegrass rather than the Southern Baptist variety, which means it will appeal to those who like rock’s rootsier forms as well as to those who grew up on grits and Smithfield ham.

“You know, we have been classified as a bluegrass band because we play the traditional instruments of a bluegrass band,” explains the affable and easygoing Fleming, on the line from his Nashville home. “But I’ve never felt that we’ve been a traditional bluegrass band, and our name, the SteelDrivers, is kind of the same as the music. You know, it drives, it’s got propulsion to it, and it does have more of the feel of a blues-rock band at times. And part of that is that we’ve always had a lead singer that, instead of being a high tenor in the sense of someone like a Del McCoury, they’ve been a blues singer. So that’s differentiated us from other acts in the bluegrass genre.”

In fact, the SteelDrivers have had two bluesy lead singers, with founding member Chris Stapleton leaving the band just after recording its second effort, Reckless, in 2010. That makes Hammer Down something of a resurrection for the quintet—as well as a fine showcase for Nichols, his replacement.

“When Chris decided to leave, that was tough,” Fleming admits. “But everybody had enjoyed the first record, and the second one was in the can, so the decision was to see if we could keep going. And we got a great stroke of luck in finding Mr. Nichols and his voice, which is similar to Chris’s, although nobody duplicates anybody exactly. And Gary’s not trying to replicate Chris: it just so happens that he grew up in Muscle Shoals, Alabama, and is an electric blues-guitar country player. So it was just kind of a perfect match.

“I think we’ve got the most musical band we’ve ever had right now,” he adds, and that’s an assessment shared by one international star: Brit-soul chart-topper Adele, who’s been performing the band’s “If It Hadn’t Been for Love” in her shows. “They’re a blues, country, bluegrass swagger band and they are brilliant,” she’s been quoted as saying—and that’s a better description than “unknown supergroup” could ever be.

The SteelDrivers play a Rogue Folk Club show at CBC’s Studio 700 on Thursday (April 10).