A direct comparison, using three identical floor-ceiling assemblies, which did not meet minimum building codes standards for impact insulation class as built. Each floor-ceiling assembly received different corrective measures in an effort to correct the deficiency. All corrective measures were limited to the bottom side of the assembly, since hardwood flooring was installed as the finished floor. All the floor-ceiling assemblies consisted of light weight 16-in. deep ‘‘I’’ beam structural framing members (joist) spaced at 24 in. center to center supporting 3/4 in.-t & g plywood with 1-1/2 in. light weight gypsum concrete covered with 1/2-in. plywood and finished with hardwood flooring. Using tired old industry standard methods, products, and systems the best impact insulation class increase was twelve points which still did not meet minimum building code standards. By installing the state of the art products, using the proper methods available today under the floor-ceiling assembly the field impact insulation class was increased 28 points to a field impact insulation class of 60 without acoustical mat on the top side of the assembly. By design the field sound transmission class was also improved (40 to 55 STC) due to product selection, installations procedures, and design.