There are two kinds of people: Those who have yet to see Brittany Howard sing, and the converted.
The 24-year-old Alabama Shakes frontwoman seizes attention through gritty, powerful blues-rock vocals. Her mouth emotes as much as her voice, forming a perfect "o" on the chorus of the Shakes' hit "Hold On."
But it's the ease with which Howard commands the stage and how she shared it so effortlessly with Elton John and Mavis Staples at the recent Grammy Awards that sets her apart. Old-soul poised, Howard makes belting look as natural as breathing.
Performing alongside music legends at the Grammy tribute to Levon Helm did not intimidate Howard. She came up in Alabama bars and clubs and is used to defying expectations.
"I like it when people are skeptical," Howard said by phone from her hometown of Athens, Ala., a community of 22,000 near the Tennessee border.
Alabama Shakes, a band rooted in a high school psychology class Howard shared with bass player Zac Cockrell, favors a style of dress that's part Southern bohemian, part just-rolled-out-of-bed. The group received dubious looks at early shows at bars in Huntsville the closest big town to Athens where the beer flowed and patrons wanted cover tunes, not originals.
"They would look at us come in, and people would think the band was going to suck," said Howard, who will play a sold-out show with the Shakes on Wednesday night at UC Davis' Mondavi Center for the Performing Arts. (Howard's drawl on the phone is a bit unexpected, if only because so many Southern rock musicians soften their accents when they hit the mainstream.)
The Shakes won over Huntsville a gig at a time, then hit stages 90 miles north in Nashville, where the band members built an avid following while working day jobs (Howard was a postal carrier) back in Alabama.
"The very first time she opens her mouth, you wonder, 'Who is this girl?' " said Dave Rossi, program director for Lightning 100, a Nashville radio station that was an early Shakes supporter.
Alabama Shakes' debut album, "Boys & Girls," drew critical acclaim upon its release last April and later, three Grammy nominations. But awareness exploded this past month with Howard's Grammy appearance and the band's knockout performance on "Saturday Night Live."
That one-two punch sent "Boys & Girls," which had peaked at No. 8 on the Billboard albums chart, upward again, moving 23 spots to No. 20. Howard's magnetic stage presence became a national topic the way it once was a topic in Southern nightclubs.
Howard is getting a taste of the band's current buzz, but only secondhand. Family members report to Howard that people are congratulating them at the gym in Athens. Other good wishes and media inquiries are filtered through the band's publicist.
"I just sit here in bed, watching Netflix," Howard said with a laugh.
"Here" is her dad's house, but soon she will move into her own place in Athens.
"It's huge," she said. The house isn't huge, but buying one at 24 is. "It is amazing. I have never lived anywhere nice my whole life."
She has friends in Nashville, but she'll stick with her blue-collar hometown.
"It's not perfect, but it's home," Howard said. "Pretty much all my family is in Alabama." Howard's mother and "nana" accompanied her to the Grammys, and a great-uncle the musician in the family was the first person to encourage her to play guitar.
Howard's "down-home" quality is part of her appeal, Rossi said.
"She is so the opposite of everything that is out there right now," he said.
It's hard not to concur when Howard's closest female contemporaries at the Grammys were Taylor Swift and Rihanna artists whose voices and images never could be called unvarnished.
"If you see (Howard) walking down the street, she seems like the most unlikely rock star, but she is a rock star," Rossi said. "As soon as she walks on stage, there is a confidence. But it's not flamboyant at all. ... There's almost a simplicity."
Howard started out playing drums in her grade-school band, taking up guitar at 13 so she could write songs. She sought out Cockrell in high school because he played bass. She wasn't sure if they were musically compatible, but chances of meeting fellow rock musicians in Athens were slim.
"I thought, 'This is my only option,' " Howard said. "We weren't friends at first. We became friends later."
She was rootsy. Cockrell's tastes were more diverse and modern, and included hip-hop. Together, they experimented with prog rock. They added drummer Steve Johnson and guitarist Heath Fogg also Athens musicians and the foursome played Led Zeppelin and Otis Redding covers along with original songs.
Howard seems hesitant to tie the Shakes to a particular genre, and with good reason. "Boys & Girls" sounds retro with a 2012 polish, covering a spectrum of popular music from Allman Brothers Southern dirt to Burt Bacharach California breeze without specifically resembling anyone.
Howard's and Cockrell's influences "don't stop," Howard said. Vocally, "I like anyone who does what they want," Howard said, citing David Bowie, the late AC/DC singer Bon Scott and inventive indie musician Ariel Pink (also male) as examples. "Doing what they want naturally that is who I respect."
Howard often gets compared to Janis Joplin. She's a big fan, but sees the comparison as too facile.
"I think people hear my voice and it is not a clean, pretty voice," Howard said. " 'Here is a woman who sings with power and is kind of raspy.' And they compare me to Janis Joplin. I don't think it's a fair comparison."
The band's show Wednesday night at the Mondavi Center is sold out, but the Shakes will return to the area May 10 for the BottleRock festival in Napa. Day pass: $139, www.bottlerocknapavalley.com
For a taste of Alabama Shakes, visit its website (www.alabamashakes.com), where "Always Alright," one of the songs the band performed on "Saturday Night Live," is a free download. (Warning: The song contains profanity.)
And if you like female- fronted blues rock bands, check out Heartless Bastards, led by the remarkable Erika Wennerstrom, coming to Harlow's on March 31 ($15, www.harlows.com).