An acoustics simulator is a complex of signal processing equipment by which the acoustical characteristics of one space may be simulated in another. Artificial reverberation systems, theater surround systems, and four-channel stereo systems are familiar examples of relatively simple simulators. A more comprehensive simulator can be useful in auditorium acoustics research because it enables the experimenter to control and rapidly alter important acoustical parameters, thus permitting facile psychoacoustical testing. We describe a recently completed auditorium acoustics simulator, which has loudspeaker channels for up to 12 arrival directions. The impulse response for each channel is individually programmable from combinations of “direct” sound, “reverberation,” and “discrete echoes” generated from magnetic tape delays. Design features are convenient programmability of desired directional impulse responses, and the facility for instantaneous comparisons among a number of combinations of such preprogrammed sounds.