By Mario Tarradell / The Dallas Morning News

Susan Gibson's voice defines the Groobees. Ms. Gibson, lead singer of the Amarillo-based folk-country-rock band, possesses clear, crisp, bold pipes. Her vocals have a rough edge that is tempered by a potent sense of melody. When she sings, you can see her body surge with energy. She's pulsating with every word.

And you know she's loving the experience. Onstage before a sold-out crowd Friday night at Poor David's Pub, Ms. Gibson and her five bandmates (for this gig, extra Groobee Jeff Plankenhorn was on dobro duty) offered two sets – almost three hours – filled with lively, rootsy musicianship and honest songs.

The gig celebrated the release of their latest album, Buy One Get Eleven Free. Of the fresh songs, the best were "Perfect World" and "Sorry, Jack." "World," a country-rock corker spiced with accordion, was frenetic fun. Written by Ms. Gibson as a sometimes sardonic but sincere appreciation of a singer-songwriter's life, the tune never let up. Between the hard-driving beat and the in-your-face vocal delivery, there was no escaping its grasp.

"Sorry, Jack" was similar in sound but not content. This time, Ms. Gibson writes about a crumbling relationship that she's trying to flee. There was fire in her voice when she sang, "I'm sorry, Jack, but I'm no Jill/I'm not going down that hill." She's probably lived those lines.

Indeed, nothing about the Groobees comes off contrived. The musical interplay between band members is a marvel to watch. Ms. Gibson frequently turned the mike over to keyboardist, accordionist and guitarist Scott Melott. One of the finer tunes on Buy One Get Eleven Free – a breezy number titled "Down in Flames" – features Mr. Melott on lead vocals. Lead guitarist Gary Thomason earned plenty of attention, not only for his passionate riffs but also for a hilarious take on Tennessee Ernie Ford's classic "Sixteen Tons" that arrived early in the second set.

Mostly, there's an easygoing charm to the Groobees. Their music maintains a small-town personality as it deals with big-city issues. The connection to Friday's audience – or any crowd, for that matter – was instant and effortless.

So it's no wonder Dallas' megaselling country trio the Dixie Chicks found a future mainstream anthem in Ms. Gibson's "Wide Open Spaces." The song remains a Chicks staple; it's also the biggest hit from the group's 10 million-selling major-label debut of the same name.

But the Groobees did it first, and Ms. Gibson sang it with relaxed eloquence. That song also defines the Groobees. Seven years ago, the band valiantly ventured out to conquer Texas, a state filled with wide-open spaces.