“Grandeza” arrives at National Sawdust as a live classical program shaped for younger listeners as well as adults. Featured performers include Sergio Sayeg and Sessa, bringing distinct musical lineages into a concert setting that favors clarity and close listening. In a city where “for kids” often means simplified programming, this format treats attention as a skill to be practiced, not catered to. If this is a New York premiere, its significance lies less in novelty than in how it broadens who classical music is allowed to address.