The fourth annual BUZN Half DUZN country concert had a revamped format Tuesday at Mystic Lake Showroom.

Sponsoring radio station BUZN 102.9 decided to divide the half-dozen country performers in half for two separate sets instead of the usual six acts sharing the stage at once. The singers then performed in round-robin fashion four times.

The opening segment belonged to three new duos – LoCash, Maddie & Tae and the Brothers Osborne. The closing portion featured three veterans – Craig Morgan, David Nail and Trace Adkins. Both sets had plenty of rewards.

Here are a few thoughts:

Fresh from the Grammy Awards, the Brothers Osborne are very talented even though it was just them with acoustic guitars. Long-fingered John Osborne is a gifted lead guitarist and T.J.Osborne had a star's voice, deep, easy and emotional. Loved their bluesy new song "It Ain't My Fault" and, of course, the Grammy-nominated hit "Stay a Little Longer," which the Osbornes said BUZN has played more than any other radio station.

LoCash proved to be a chatty, friendly hat act – a fedora and a ballcap, with sidemen in a stocking cap and backwards ballcap – that suggested a new version of Big & Rich with stronger vocals. LoCash sparked a lot of the conversational by-play between the three duos.

The Brothers Osborne

Visually, Maddie & Tae looked right – one left-handed and one right-handed acoustic guitarist. Their lyrics are clever and cheeky (loved "Girl in a Country Song") but their high-pitched twangy voices are too similar. Imagine Dolly Parton harmonizing with herself.

Craig Morgan's robust voice projected like an opera singer through a megaphone. It was a little too bright. At 51, the enthusiastic '00s star may be past his prime but the crowd responded enthusiastically to such hits as "International Harvester."

Even though David Nail, 36, mentioned how he didn't feel he belonged with the other two established veterans, he showed a distinctively soulful voice. His material was not especially memorable save for "Let It Rain," whose chorus Morgan spontaneously reprised as a sing-along after Nail had finished. Nail also proved to be the most talkative of the three solo acts, telling a story about how he and his wife have bonded with Trace Adkins' daughter Tarah.

Former "All Star Celebrity Apprentice" champ Trace Adkins, 54, tall and laconic, showed off his distinctively deep voice on "Every Light in the House" from the mid-'90s and the brand new "Jesus and Jones" (about singing gospel music as well as honky tonk tunes) from his upcoming album.

All half-dozen acts – and their various backup musicians – took the stage for the encore, a suitably sloppy and fun rendition of Hank Jr's "Family Tradition."