Clearly enthused that last night’s concert at Masonic Auditorium was the last date of a lengthy U.S. tour, the guys in the Brit pop-rock band the 1975 reveled in the atmosphere of the show. Teenage female fans made up the bulk of the capacity crowd and their enthusiasm was undeniable. They screamed and cheered for every move that rail-thin singer Matt Healy made. While the band’s mix of pop and rock often landed too softly, the blinding light and stage show that came complete with smoke machines was impressive even when the band wasn’t. The 90-minute concert started strong, faltered a bit in the middle as it got bogged down by ballads such as “fallingforyou” and then finished with a bang as the band delivered the snotty pop tune “Girls,” one of the singles from last year’s self-titled debut. The encore included the brittle “Medicine,” a terrific dream-pop tune that sounded sharp, even with the auditorium’s shaky acoustics.