Visualizing reflections in rooms with computer graphics

A computational technique has been developed to calculate and display, in two dimensions, wave fronts from a point source reflected in rooms of variable shape. The reflections are generated in a series of time frames, generally at 10-ms intervals, for both a plan and section of the room. The technique calculates reflections from re-entrant surfaces such as balconies and suspended ceiling panels, and it includes variation in sound intensity and surface absorption. Rapid changes may be made in room shape and source location. Visual estimates can be quickly made of intensity distribution and arrival time of early reflections. The method has been used to examine some acoustical qualities of existing auditoriums, to evaluate the effects of remodeling room shapes, and to demonstrate acoustic defects.