Jason Isbell and the 400 Unit, Communist Daughter

9 p.m. Dec. 15 at Buster's Billiards & Backroom, 899 Manchester St. $15 in advance, $18 day of show. (859) 368-8871. Bustersbb.com.

When your artistic reputation is staked so solidly on live performance, the release of a concert album becomes something like a rite of passage. And so it is for Jason Isbell.

Since amicably splitting from Drive-By Truckers in 2007 after a six-year stay, he has established his own name as an expert songsmith who meshes the sounds and lyrical inspirations of his Alabama heritage with a strong country/Americana sensibility. But the fan base earned in the five years since fronting his current band, the 400 Unit, has come mostly through a religiously rigorous touring schedule that has finely honed his sound and his songs.

So it is any wonder that his new album, Live in Alabama, is something of a mile-marker? It presents a tight, soulful and often reflective maturation of Isbell's music.

And, yes, the fact that the album is pulled from concerts performed on home-state turf doesn't hurt.

"I think the purpose of any album, really, is to record a certain group of people at a certain moment in time," said Isbell, 33, who returns to Lexington this weekend for a performance Saturday at Buster's. "It kind of charts your creative evolution.

"You try to keep challenging yourself and challenging your audience. We've come to a good point as a band. We've gotten very consistent and very familiar with each other over the years. So I thought it would be a really good time to try to capture that, get it down and get it out to folks so they could listen to it.

"The music is constantly evolving. I feel like I have a pretty solid catalog of songs to pick from now. That was another reason I wanted to do the live record: to consolidate a lot of that material from the last 10 to 12 years."

A highlight of both the record and Isbell's "evolving" sound is Alabama Pines, a song with a country spirit both restless and homesick. A tune that, in essence, pines for the pines, it first appeared on Isbell's third and newest studio album, 2011's Here We Rest.

In September, Alabama Pines was named song of the year at the Americana Music Association's Honors & Awards ceremony in Nashville.

"In that particular circle, I think it means more to me than it would in other groups," Isbell said. "You look at the Grammys every year. Some acts wound up getting those things, and you know they didn't write any of their own songs or really sing that much on their own recordings.

"That kind of thing just doesn't happen in the Americana world. They're not about whatever is most popular. They're going on what they feel like has quality to it. So it was really nice to be judged as something of quality by those people. They have been influences and inspirations for a long, long time."

Saturday's performance also comes with a note of caution. This might be your last glimpse of the 400 Unit for awhile. Isbell plans to devote 2013 to recording and promoting a solo recording. A few audiences caught a glimpse of a solo, acoustic Isbell last year, when he toured as an opening act for the similarly unaccompanied Ryan Adams.

"The songs I have right now will fit really well in that kind of a setting, so I think that's what you have to go with. You have to make a decision based on where the songs feel like they want to be played and how they're going to be recorded."