Light in the Attic Records celebrates 10 years of crucial album-reissuing with three distinctive artists. Michael Chapman is a British folkadelic maverick; Donnie and Joe Emerson are freakishly funky, soulful farm boys who’ve never played the big city before; and Rodriguez is a Dylanesque Detroit troubadour who’s bigger than Elvis in South Africa and, before the documentary Searching for Sugar Man exposed his scathing brilliance to the masses, an unjustly obscure figure in America. (Showbox at the Market, 1426 First Ave,, 8 pm, $15 adv/$18 DOS, all ages)