Arguably the finest extant '80s underground rock act to return to service, Boston's Mission of Burma were never particularly popular beyond the cognoscenti, and their comeback shows weren't mobbed like those of the Pixies. But where Black Francis & Co. will never be anything more than a nostalgia act, MoB has released more music since their 2002 return than they did during their initial four-year tenure. What's more, their latest album, Unsound, may be their best to date. It's shrouded in dilapidated post-industrial grime that recalls Pere Ubu's art-punk spirit, and guitarist Roger Miller, whose battle with tinnitus first shelved the project, wields his six-string like piano wire, vacillating between chiming riffage and decapitating squalls. While they typically balance their noisier impulses with surreptitious hooks, the former wins out on Unsound. Austin's The Gary open.