From rock to country, Shelby Lynne shines

Shelby Lynne showcased a full array of emotions in her show Wednesday night at Somerville Theatre. (Jay Connor for The Boston Globe)

SOMERVILLE - Shelby Lynne is a captivating combination of steely gaze and soft heart. You could bounce a quarter off her outer shell, but work your way into one of the nicks in the facade and she's pure silk, soothing and vulnerable.

Wednesday night at Somerville Theatre she was equally convincing excoriating a neglectful lover in "Leavin' " as she was desperately begging an abusive one to stay on the heartwrenching "Pretend."

Those juxtapositions startled and stung during a 95-minute set that could be as electric as a rock show and as sedate as a cocktail lounge. Lynne worked through her catalog and the facets of her musical and emotional personalities: country firebrand, torch singer, shattered pop balladeer.

That last persona got a vigorous workout thanks to songs from "Just a Little Lovin'," her recent tribute to Dusty Springfield, a vinyl copy of which she gave to someone in the front row. Instead of imitating Springfield - which, with her powerful pipes, she could - Lynne radically downshifted, stripping the tunes to their emotional essence with the help of a four-piece band keenly attuned to the nuances of both song and singer.

Thus, "You Don't Have to Say You Love Me" began as an a cappella lament and built quietly to a poignant acoustic guitar solo that encapsulated the song's forlorn heart. "Breakfast in Bed" was more playful with an infusion of rolling and tumbling bass and electric guitar heat. "Willie and Laura Mae Jones" featured some of Lynne's best vocalizing as her sultry lower register swooped over the stutter and click of the crisp, bluesy backbeat. As she said herself, "songs this good just don't get old."

Given the generally hushed nature of the Springfield material, Lynne's originals were eagerly received. The greasy slide-guitar churn of "Life Is Bad," the snappy Southern soul of "Gotta Get Back," and the anthemic "Jesus on a Greyhound" offered welcome energy spikes.

Effortlessly sexy in a black vest and low-slung jeans, the diminutive blonde - who looked a bit like Amy Poehler after some hard lessons learned - repeatedly expressed her appreciation for the "lovin' " the audience was giving her. She even turned forgetting the lyrics to her last song into an act of thankfulness. When, halfway through "Iced Tea," she exclaimed, "Ah, hell, it don't matter. I love you all. Goodnight," it was hard to feel cross with a performer so willing, and grateful, to let down her guard and share a bit of her soul.

Charismatic opener and one-time Bostonian Jim Bianco split the difference between Lyle Lovett and Tom Waits with his witty and thoughtful songs about love, stalking, and favorable winds blowing up skirts.