Marcia Ball understands what makes the blues such a universal sound.

“I can appreciate other, more ‘sophisticated’ styles of music,” said blues singer-pianist Ball. “Still the style and the back beats [of the blues] are what move me viscerally, and I suppose that’s what other people respond to. The blues have a history of being the people’s music, or being their way of dealing with hard times.”

Ball, a Louisiana native, will perform at 3:20 p.m. Sunday on the Maine Stage of the North Atlantic Blues Festival, set for this weekend in Rockland. She’s looking forward to the event.

“That’s how we get to see our friends, and see other bands play,” she said by phone. “I just wish I had more time. I’ll have to pop in and out because of my [touring] schedule.”

It’s been a time of transition for Ball, who’s been singing the blues for more than 30 years. After most of two decades recording for Rounder, she moved to the blues-oriented Alligator Records. She’s been happy with the switch.

“It’s been very productive,” said the 51-year-old Ball. “But I knew that going into the deal. They don’t put out many records each year, and they concentrate on the artists and promoting the albums. We’re just wearing each other out. They’re going above and beyond the call.”

Her first album for Alligator, this year’s “Presumed Innocent,” marks a change for Ball. She’s known as a performer who creates a party on stage, yet the new release has a marked increase in slower songs.

“I’d always had a ballad or two on each record,” she said. “But this is not like anything I had ever recorded. I was hoping that it would be well received, and so far it has been.”

How does Ball, who both sings her own songs and interprets those of others, decide what works for her?

“When I like a song so much that I don’t want to play it for anybody, for fear that they’d steal it, that’s when I know it’s going to work for me,” she said. “[When writing] I write whatever I have when I sit down. I don’t argue with my muse, I take what it gives me, and sort it out later.”

For more information on the North Atlantic Blues Festival, access www.midcoast.com/~bluesman/.