An acoustic perforation method and assembly for forming holes or perforations into a face sheet of a sandwich panel without damaging a honeycomb core thereof. The method may include photographing or otherwise scanning the face sheet bonded to the honeycomb core after cure, then detecting locations of cell walls of the honeycomb core via image processing or analysis of scan data obtained. For example, discolorations on the face sheet or coatings applied thereto may indicate locations of the cell walls of the honeycomb core. A perforation pattern may then be generated or altered based on the detected locations of the cell walls, and a perforation device may be commanded to perforate the face sheet in accordance with the perforation pattern at locations where the cell walls are not located.