Computer simulation of electroacoustic reverberation enhancement systems.

Computer simulation of electroacoustic reverberation enhancement systems (RES) for auditoria is described and compared with actual measurements. The simulation proceeds in two stages: First, the room impulse responses (from the source and all loudspeakers to the receiver and all microphones) are predicted using the mirror image method, which is then complemented by a diffuse field extension for the late part. The electronic units (amplifiers, delays, and reverberation units) are specified by their impulse responses. Second, the impulse responses are convolved and added using a matrix formulation. This yields the total room impulse response of the hall with the RES installed and objective criteria can then be calculated. Auralization is also possible by convolving the total impulse response with anechoic source signals. More complex systems can be studied than was possible with previous methods since transducer directivities and individual channel reverberation can be included. It is shown that these parameters, along with the system delay, to a large extent influences the early part of the total impulse response. The risk of instability of complex systems can thus also be studied.