Boosted by the power of “Kryptonite,” 3 Doors Down is flying as high as the comic book hero Superman of whom they sing, selling more than 6 million CDs since the group's hit single hit the charts in 2000.

The Grammy-nominated band, which will headline tonight's concert at the Toledo Sports Arena with Shinedown and Tantric, has toured with the endurance of the Man of Steel, including Toledo shows in 2000 and 2001, as it continues to polish its guitar-powered sound that it calls “good ol' American rock and roll.”

Formed in the mid-1990s by singer-drummer Brad Arnold, bassist Todd Harrell, and guitarists Matt Roberts and Chris Henderson, 3 Doors Down got its first break when a self-produced demo version of “Kryptonite” got a spin on a small Mississippi radio station.

Arnold said he came up with the catchy rock riff while daydreaming in high school algebra class.

The non-mathematical formula paid off as the radio station's phones were soon flooded with requests for more #8220;Kryptonite.”

The buzz grew until 3 Doors Down found itself being courted by the major labels, eventually signing with Universal's Republic Records.

It wasn't long before 3 Doors Down was playing to crowds far bigger than the population of its hometown, Escatawpa, Miss. (3,902).

Its major label debut, “The Better Life,” earned multi-platinum status for sales of more than 6 million copies and produced a string of hit singles including “Loser,” “Be Like That,” and “Duck and Run.”

“Away from the Sun,” 3 Doors Down's second disc, came out in November, 2002, and produced the hit singles “When I'm Gone” and the title track.

Arnold said most of the lyrics on the second disc deal with loneliness, a condition that the musicians felt while touring almost nonstop for two years.

Harrell said he was away from home so often that when he finally made it to his own house, his dog didn't recognize him and tried to bite him.

Arnold said tried to find a positive outlet for the band's sense of loneliness.

“I was feeding off those feelings of isolation,” he told Rolling Stone. “With these songs, I wanted to convey to the listener that he or she is not alone — there are a lot of people who feel the same way.”

The latest release from 3 Doors Down is a six-song EP, “Another 700 Miles,” recorded live in concert in Cleveland, Cincinnati, and Chicago. Released last month, the EP includes new versions of “Kryptonite,” “When I'm Gone,” Lynyrd Skynyrd's classic “That Smell,” and a new 3DD tune, “It's Not Me,” focusing on a marital split.

Opening tonight's concert will be the rock groups Shinedown and Tantric.

Shinedown, a four-man band from Jacksonville, Fla., released its major-label debut, “Leave a Whisper,” in July on Atlantic Records. The band's lead singer, Brent Smith, said the group has an old-school rock style that echoes such musical icons as Led Zeppelin, Allman Brothers, and Lynyrd Skynyrd.

“We're a four-piece rock band, playing hard. We're not trying to reinvent the wheel or anything,” Smith told one interviewer.

Tantric hails from Louisville, Ky., and has scored modern-rock hits with “Astounded,” “Mourning,” and “Breakdown,” the latter tune having been featured on the soundtracks to the TV shows Buffy the Vampire Slayer and Witchblade.

The group, featuring lead singer Hugo Ferreira and former Days of the New musicians Todd Whitener, Jesse Vest, and Matt Taul, recently released its sophomore disc, “After We Go.”

First Published January 2, 2004, 12:41 p.m.