More than 21 years ago, I saw the Minneapolis rap group Atmosphere open a show at New York’s Knitting Factory. At that show, the late Eyedea was Atmosphere’s hypeman, and they were great. The bill also included a couple of standout New York underground acts, J-Live and MF DOOM, all opening for Chuck D’s terribly and justifiably forgotten rap-metal group Konfrontation Kamp. DOOM and Atmosphere soon became underground rap institutions, and DOOM released his 2004 album Mm..Food on the Atmosphere-affiliated Rhymesayers label. We lost DOOM last year, but now he’s made a posthumous appearance on Atmosphere’s new song “Barcade.”