Marc Rieffel
Geoffrey Noer
Jeremy Dilatush
Andrew Brown
E. Carr Everbach
Dept. of Eng., Swarthmore College, Swarthmore, PA 19081-1397
An enhanced version of a previously presented geometrical ray-tracing program for the Macintosh [M. Rieffel and E. C. Everbach, J. Acoust. Soc. Am. 91, 2373(A) (1992)] will be demonstrated. The program accepts input files of auditoria created in any of several popular CAD programs that export standard DXF formats, displaying the auditorium in 3-D projection. The user specifies the surface absorption coefficients of all internal surfaces and the placement and characteristics of sound sources. The user also specifies an arbitrary ``monitor'' plane passing through the hall, each point of which will be a receiving location in the subsequent simulation. When the simulation is run, rays are propagated between source and receiver, allowing the computation of an echogram for each point in the monitor plane. In this way users can discover focusing, dead spots, or late reflections at specific locations in a proposed hall design. The program is available for consultant or instructor use, and will be demonstrated during the session.