Thao Nguyen at First Unitarian

Her shoulders shaking and her feet stomping the stage, Thao Nguyen played her guitar with her whole body, not just her hands, in the basement of Center City's First Unitarian Church on Friday night.

Blending styles as diverse as rockabilly and tropicalia, she strummed with a light, staccato touch, never letting a chord resound for long. In "Moped," she mimicked the stutter of an engine by tapping the strings with the handle of a toothbrush, which bounced and skittered in her hands.

Nguyen's songs are always forming and re-forming themselves, falling apart and slamming back together. Dissolution and stability play recurring roles in her lyrics, although it's never quite clear what side she's on.

"Shake the frame of this house, distress the wood, make it shout," she sang in "Bag of Hammers," whose wordless chorus came shouting back at her from the crowd. Strongly influenced by Cat Power's Chan Marshall, she shifted abruptly from a croaking half-whisper to a defiant shout.

Nguyen, who sometimes tours on her own, was accompanied by her two-man rhythm section, the Get Down Stay Down, and a rotating cast of guests drawn from the supporting acts. Sister Suvi's Merril Garbus added distorted ukulele and vocals, while Oklahoman Samantha Crain banged on a cymbal and wielded shakers.

Earlier in the evening, Crain opened the show with her band the Midnight Shivers, which backed her haunted narrative with an echoing twang.

Although she stumbled over her guitar cord once or twice, Crain played with a confidence belying the fact that her first album, Songs in the Night, was released only last month. But as a singer, she strived too hard to sound wise beyond her years, bending words into unrecognizable shapes and torturing vowels until they yielded superfluous syllables. "Devils in Boston" spun a cautionary tale of big-city corruption, but its ominous atmosphere never settled into anything concrete.

It was as if she had developed her voice without entirely finding it first.