The Basilica Block Party is not for another couple weeks, but it sure felt like Minneapolis' beeriest church bash arrived early and moved out to farm country for Saturday's twofer concert by the Avett Brothers and Brandi Carlile at Somerset Amphitheater.

Both Basilica alumni — the Avetts were even one of last year's BBP headliners — the pair of rootsy Americana performers already proved good fodder for summertime fun at the Basilica's crowded, flat, downtown blacktop setting, what with their big singalong moments and generally warm, arms-around-your-sweetie vibes. So you can imagine how much cozier, friendlier and warmer the party felt on a spacious, hilly, ultra-green riverside field on a pink-skied, 70-degree evening at the refurbished amphitheater in Somerset, Wis.

"It don't get any better than this," Carlile said after her opening song, "Hard Way Home."

Saturday's Somerset crowd was only half as large as a Basilica party, with about 6,000 tickets sold, but Carlile and the Avetts played more to their faithful audiences there. In fact, Carlile seemed to have nearly as many fans rabidly devouring her set as did the headliners.

With a rock-solid voice that's part Melissa Etheridge inflamed and Patsy Cline torchy, the Seattle-area singer-songwriter (age 32) rolled along from feisty rockers to tender power ballads to straight-up country in her 75-minute set. Her twangability was evidenced nicely by both the poetic original "Keep Your Heart Young" and the set-ending cover of Johnny Cash's "Folsom Prison Blues."

Carlile's rocky side proved less solid, though, with "Raise Hell" coming off like a hokey, forced fist-pumper — like something a hat act of the Kenny Chesney variety might try to pull off to beef up his sound. But she showed plenty of full-tilt power later with "The Story." Best of all, she soared highest when the music was at its quietest, as in the piano hit "That Wasn't Me" and the cello-accompanied "What Can I Say."

The Avetts similarly made their strongest impressions when they were least trying to rock the crowd like a hurricane. Although they did come up playing to excited crowds at punky rock clubs like First Avenue, North Carolinian brothers Scott and Seth Avett have outgrown a lot of the hyperactive, earnest sound of slam-grassy songs such as "Go to Sleep" and "Colorshow," both of which felt like filler in Saturday's lengthy, two-hour, 25-song set.

By sharp contrast, the emotional centerpiece of their performance came when the two namesake brothers played "Ten Thousand Words" and "When I Drink" as a tightly harmonized acoustic duo, a style reprised later for the pre-encore finale "Life." The crowd favorites "Kick Drum Heart," "I Never Knew You" and "Head Full of Doubt, Road Full of Promise" fell somewhere in between, tempo- and volume-wise. But holy cow, it sounded like even the bovine population around Somerset got in on the singing along on those tunes. Everyone joined in.

In addition to the two main draws, Saturday's concert featured two highly charming openers: Texas newcomers the Wheeler Brothers, who came off like a twangy roots version of the sandy-voiced '90s band Toad the Wet Sprocket, and Philadelphia hippie soul-pop sextet Dr. Dog, whose catchiness easily caught on in such bouncy rockers as "Old Black Hole" and "These Days."

"You guys got a really nice place here," Dr. Dog bassist/co-vocalist Toby Leaman commented, never-minding the fact that his band lost a gig last-minute last summer when the amphitheater's SoundTown festival was abruptly canceled.

A couple more undeniably good-vibration summer outings like Saturday's concert, and SoundTown and any other past woes at the resilient amphitheater could soon be forgotten.

See a concert photo gallery and Saturday's set lists at startribune.com/artcetera.

Chris Riemenschneider • 612-673-4658