Scott and Seth Avett used to wind down after gigs with their rock band Nemo with post-show hootenannies. The alt-country trio has since become the Avetts’ full-time group. Joined by stand-up bassist Bob Crawford, the Avett Brothers layer three-part harmonies over bluegrass tunes that often drift into pop and punk territories. The North Carolina band has maintained a busy tour calendar that rivals its prodigious recording schedule — which has yielded a solid set of records over the past eight years. Emotionalism, from 2007, tightens the screws and polishes the chassis on the Avetts’ Americana, offering a strong batch of songs that range from the lonesome country rag “Paranoia in B-Flat Major” to the flamenco-flavored flower-power rave-up “Pretty Girl From San Diego.” It’s restless, ambitious music that never sits still for long. They’ve got a new record due soon. You can expect to hear some new tunes when they play the Akron Civic Theatre (182 S. Main St., 330.253.2488, ticketmaster.com) at 8 p.m. Samantha Crain & the Midnight Shivers open. Tickets: $26. — Chris Parker