Released in 1995, “Down” is the sound of a band going from underground to mainstream without selling their musical souls. 311′s breakthrough hit elevated their rock-reggae-rap roots and road-hewn chops with supersonic production. Crucially, amid that era’s MTV-fueled alt-rock boom, the track was accompanied by a music video that looked just as good as “Down” sounded.

When the song was written in ‘94, 311 singer/guitarist Nick Hexum says, “We were listening to a ton of like riff-rock Helmet, Bad Brains, Soundgarden, you know, stuff like that.” A single off the band’s self-titled third album and major-label debut, “Down” originated from a funky/heavy guitar riff Hexum came up with. “There’s a lot of off-beats and it’s very syncopated and unusual,” he says. “I wanted a super, hard-rocking song but also wanted like a really uplifting chorus.”

The lyrics were, Hexum says, “about saying thank you both to my bandmates and fans. We’ve been through a lot together, so if I never did thank you then just let me do it now. Those first couple of years [in a band] seem like a really long time because you’re packing so many first things in them. So [that song] was almost like a retrospective. even though we were only like four years into being. But it still rings true more than ever, 30 years later.”

“Down” became a chart-topping rock hit and that album, produced by Ron Saint Germain, a studio wiz who’d worked with acts from Kraftwerk to Living Colour to Sonic Youth, went multiplatinum. The ‘95 self-titled LP birthed another smash, “All Mixed Up.” 311′s following albums contained hits like “Beautiful Disaster,” “Come Original,” “Flowing,” “You Wouldn’t Believe,” “I’ll Be Here Awile” and “Amber.” The latter song, a reggae ballad from 2001, has since been streamed around 275 million times on Spotify.

Hexum checks in from a hotel room overlooking Niagara Falls on a day off from 311′s “Unity Tour” with support acts AWOLNATION and Neon Trees. On Thursday, the tour comes to Sand Mountain Amphitheater in Albertville, Alabama.

In addition to Hexum, 311′s still-intact classic lineup features bassist Aaron “P-Nut” Willis, drummer Chad Sexton, lead guitarist Tim Mahoney and vocalist/turntablist S.A. Martinez. The band formed in 1990 in Omaha, Nebraska. Their first gig was opening for hardcore punk icons Fugazi.

“Being in Omaha,” Hexum recalls, “which is literally smack dab in the middle of the country, we had long arms of influences where you would grab some reggae from Jamaica, maybe some grunge from Seattle, hip-hop from New York, punk rock from L.A. We loved Prince and what was going on in Minneapolis and Southern rock. We were geographically in the middle of a lot of styles and also stylistically.”

Hexum had been fascinated with beach culture ever since he was a kid, from listening to Beach Boys songs on camping trips with his dad. “And then when I heard reggae, it just took me to a different place.”

311 guitarist Mahoney’s wheelhouse was jam-bands like Grateful Dead and Phish. On bass, Willis was the band’s resident metalhead. Sexton’s drumming drew from hard-rock and jazz-fusion. Hexum says, “We have similar but also some different influence, and that’s where a band is good where everybody’s bringing a little bit something different.

With hip-hop head Martinez and Hexum, 311boasts two simpatico yet contrasting frontmen. “At first he was more of a rapper,” Hexum says. “So we’d have him come out and rap to a couple of songs, and then we just realized it was really good [when Martinez was with them] because he has a good ear. I’m more of a low baritone vocalist, and he adds more of a higher tenor range. So he always takes a higher harmony and we realized that those harmonies were a big plus of what we do.

“And it also just makes more variety in our songs because a lot of times, I’ll write like a verse and a chorus and then I’ll leave the second verse open for him, and then he’ll come up with a different melody. And so it, I guess, inserts more creativity to have a different take on a verse. Then live, we play off each other — he has so much energy live.”

After a few early indie releases, 311 relocated to Los Angeles and inked with Capricorn Records, the rebooted Southern rock label known for classic Allman Brothers releases. In addition to 311, Capricorn’s ‘90s roster included bands like jam-bands like Gov’t Mule and Widespread Panic, quirky Sacramento alt-rockers Cake and even a pre-fame country singer named Kenny Chesney.

“I think the good thing about signing to Capricorn,” Hexum says, “was they really understood what touring could do for a band. They realized we were a live-oriented band and so they guaranteed us two albums, which is pretty unusual. Usually when you sign a major label deal, they just go one by one, and if that first one doesn’t go, you’re dropped and it’s over. But they were like, ‘No, we’re gonna do this slow,’ and that’s what we wanted, ‘and then just do it through touring,’ like those Southern rock bands had done.”

Capricorn helped 311 book their first tour, in support of the band’s Capricorn 1993 debut album “Music.” That trek took them to places like storied Birmingham, Alabama rock-bar The Nick. When it came time to tour ‘94 album “Mosaic,” Hexum says, “We got rid of our house that we shared together and literally just lived on the road and did not even have a home. We’re just like, ‘We’re gonna tour until we go gold.’ And we didn’t quite make it to gold on that record [until after the band’s ‘Down’ era success], but then on the third record, everything blew up. And it was just because of the live-touring based promotion-plan that we came up with along with our Southern label.”

From the beginning, 311′s fans were pretty evenly split between females and males. “We’re not trying to be tough guys,” Hexum says. “‘Amber’ is our most successful song and that’s a song a lot of people have gotten married to, but then showstoppers like ‘Creatures (For a While)’ and stuff like that, that are really hard-rock and songs we like to close the show with. I think that we’ve always been into expressing a full range of emotions, where maybe some heavy bands get kind of trapped into just being angry or something like that.”

Recently, some 30 years after breaking big, 311 released a vibrant new single. Titled “You’re Gonna Get It,” the track begins shifts between bong-hit ambience and metallic voltage. For a while now, 311 has turned to electronic inspirations, from dubstep to trap, to evolve their sound.

“I think everybody loves in the club,” Hexum says, “when there’s like that build, build, build and then it drops, and everybody goes crazy. But we’re a rock band. I think it’s kind of an interesting and unique thing to do it all with real instruments, but to still have that big build and then the drop. And our light show [live] when we play that [’You’re Gonna Get It’] is just super epic and everybody’s jamming out. I think the thing with music is you just got to keep finding new frontiers to cross. And this one feels very fresh to us.”

This fall, 311 will drop their 14th studio album, the band’s first in five years. “I think we made a lot of steps forward as far as the writing and the production — it’s a very exciting album,” Hexum says. “We’ve picked the title, but it’s not for sure so I can’t announce it yet. It’s going to be a busy next couple of years, and we’re stoked about that.”