The loudest KSPO Dome got on Sunday, where K-pop boy band NCT 127 wrapped the Seoul leg of its "NEO CITY – THE REDLINE" tour, had less to do with anyone standing onstage. Midway through "Ay-Yo," the screens cut to members Doyoung and Jungwoo, both away on military service. Their verses played out on video while the five who were actually there held the floor, as an audience that had already been loud for more than an hour found another register. That turned out to be the logic of the entire show. The fifth tour by the SM Entertainment act, which debuted a decade ago as a nine-piece group, opened with four of those members off the stage — two have left the group, while Doyoung and Jungwoo are serving in the military. Rather than detouring around the gaps, the production kept putting them in front of the crowd. The three-night run, which opened Friday, drew about 31,500 fans. It was the group's first headlining show in Korea in a year and eight months, and the first tour with the five-member lineup of Taeyong, Johnny, Yuta, Jaehyun and Haechan. The night opened with the five strung up o