A computer modeling procedure has been developed to assess the effect of an enclosure on far-field noise levels. The model accounts for directional radiation patterns and enclosure diffraction effects for each of the six sides. Each side is represented as a point source, and for a given receiver location, all possible noise paths are appropriately weighted and summed. Application is made for several tractor shovels which use various design changes directed towards meeting Environment al Protection Agency standards. Comparisons between predictions and test measurements show good agreement.