Menlo Scientific, Ltd., 39 Menlo Pl., Berkeley, CA 94707
The first personal computer modeling software for sound system design began to appear about 10 years ago. These early programs primarily were intended as aids for optimizing the aiming of loudspeaker horns. Very little attention was given to the acoustical characteristics of the room, except for plugging-in the midband reverberation time. As the speed and power of personal computers grew, the sound system engineering programs became more ambitious and began to address acoustical characteristics. Room models, which initially were only floor plans, now had walls, ceilings, and surface finishes. Ray tracing and image modeling capabilities were included and simulations of STI intelligibility measures using the room model are offered by a number of programs. The use of image modeling can derive an approximation of the impulse response of the room. This impulse can be exported and convoluted with external signal processing programs and computer-based DSP hardware to allow auralizing. An overview and history of each of the major programs, along with key strengths and weakness, will be provided.