A method of making an article is provided, including placing at least a portion of a panel in an injection molding die and overmolding at least one molded structure on a surface of the panel in the injection molding die, wherein the molded structure includes a foam composition. An article is also provided including a material-to-material connection between the surface of a panel and a molded structure. The panel includes first and second layers and a core disposed there between, wherein the core has a plurality of walls providing a series of connected cells. Some of the cell walls have openings providing fluid communication between a series of at least 3 cells, and the opening in a cell wall has an area that is at least 50 percent of the area of a side of that cell wall. Articles such as panels, walls, or other parts with curved surfaces can be formed according to certain exemplary embodiments. The articles are useful for absorbing sound in a designed frequency range.