At the Patriot Center, the Avett Brothers try to straddle two very different worlds

The North Carolinian neo-traditionalists the Avett Brothers excel in a format that should go down as unfussily as Southern comfort food: close-in harmonies, lyrics full of homespun wisdom and time-honored, rough-edged acoustic instrumentation. They are steeped in old folk and bluegrass but compose with the vibrancy and relevance of contemporary indie rockers. Fortunately or unfortunately, the Avetts (Scott, 37; Seth, 33) have reached a mass audience.