Mother-son duo Madisen Ward and the Mama Bear on becoming instant stars in the blues/folk scene

Perhaps the most riveting of the many evocative songs on "Skeleton Crew," the debut album from the mother-son duo known as Madisen Ward and the Mama Bear, is a slightly haunted ditty called "Dead Daffodils."

A countrified, homespun scene is laid out by the lyrics and the sparse braid of two acoustic guitars. But there are dappled shadows on the bucolic setting that gradually become a portentous shroud, with Madisen Ward's unsettled vocals carrying most of the freight.

The rich resonance of his declamatory tenor turns raspy, and unexpectedly comes to a squeaky finish within the course of a single phrase. Some of the deep, throaty tones, as well as the daring volatility, are reminiscent of singer-songwriter Tom Waits.

"When I write songs that are unorthodox or imperfect because it is coming from a raw place, it reminds me of the realm when I first started writing songs, and it is a good place," said Madisen by phone last week. "There has to be a kind of freedom to it, like if I am singing higher than my register should be, or my mom and I are not really harmonizing, not following a certain template. It is hard to remain creative if the bridge is too safe."

This artistic verve is a signature virtue of the guitar-vocal duo, their tour coming to the Cedar Cultural Center on Sunday. Madisen's desire to stir things up helps tweak the clichés out of their biographical narrative as familial African-Americans from the heartland performing acoustic music.

The "Mama Bear," Ruth Ward, was an aspiring singer-songwriter weaned on Sam Cooke and anxious to take part in the folk-rock boom of the late 1960s and '70s.

"My roots lie in everything," Ruth said. "Madisen can tell you we had albums pillar to post around the house. As a teenager I loved the sound of Sam Cooke and Jackie Wilson — the depth of soul that came out of them. Etta James. I can just feel that sound, whether it is folk or soul."

Her youngest, Madisen, grew up wanting to be an actor, believing music to be the province of his mother, who still played the occasional gig at coffeehouses around their home in Independence, Mo., just outside of Kansas City. But gradually he realized that dramatic performance was also integral to being a singer-songwriter, and the strong public response when he sat in with his mother — especially when performing his own songs — crystallized the concept of a duo act.

There are undeniable elements of country blues, gospel and folk music as they deftly trade and weave guitar riffs, with Ruth harmonizing and otherwise chiming in on Madisen's lead vocals. But Madisen's instincts are the secret ingredient.

"I have a pretty good handle on the sound we are making and why it sounds different," he said. "I can tell when something is contributing to that sound or when things start to remind me too much of something I have already heard. My mom got on board with the style so she also brings things within that style."

That sense of adventure is balanced by the grounded values and verities the duo want to convey in their lyrics. When editing rough notes into a composition, Madisen keeps in mind that his essential goal is to "talk about things that have always been or always will be.

"I don't want to talk about texting or just something that is in the modern day," he emphasizes. "I don't want to talk about the phone, I want to talk about the hand that is holding it."

For Ruth, it was a belated breakthrough at the age of 63. For Madisen, now 27, it felt like destiny.

"When we all graduated [from high school], and some of my friends went abroad, I never saw myself doing that and coming back penniless," he said. "I figured I'd stay home and go to work on a career that would allow me to travel later."

On the current tour, the group is hewing to material from "Skeleton Crew," with a cover or two mixed in. Madisen, who says with a wary laugh that he allows his mother to doctor his songs during the composing process "if it's going to improve them," added that he has been working on songs for the next album while on the road.

"We might add instrumentation, maybe a horn or something, but keep any changes subtle," he said. "And I can't guarantee it will be as happy as this last one."

Apparently some companion pieces to "Dead Daffodils" are on the horizon.