The Detroit post-punk band Protomartyr was in Chicago last week to play as the opening act for Cloud Nothings in a sold-out show at Lincoln Hall. But that wasn’t the band’s only performance in town — it also played a free set on Saturday afternoon (May 3) at Reckless Records’ store on Broadway in Lake View. As usual, singer Joe Casey had a casual air about him, looking more like a professor than a punk, but the band’s noise was bracing. Protomartyr’s recently released second album, Under Color of Official Right, is well worth hearing.