Last year’s NYE extravaganza with soulful Southern roots-music heavyweights 18 South was an off-the-hook sell-out. So this year, the ante’s been upped with even more music — the engaging Seth Walker opens, and then the 18 Southers will back buddy Shawn Camp before launching into their own brand of funky fusion. It’s been a good year for the sextet, whose members — Jon Randall, Jessi Alexander, Mike Bub, Guthrie Trapp, Jimmy Wallace and Larry Atamanuik — have been busy enough on their own that they do this purely because they want to, and they’ve settled into a rich and satisfying groove that covers a big slice of musical waterfront. Keep an ear out for keyboard man Wallace’s Linus-inspired “Don’t Take My Blanket” — part of his brand-new Peanuts-themed project — that’s already a sure-fire sing-along. Doors open at 7 p.m., music starts 8-ish, and it’s first come, first served — so get there early. Cover is $30.