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Perceptual and Room Acoustical Evaluation of a Computational Efficient Binaural Room Impulse Response Simulation Method

Wendt, Torben; Par, Steven van de; Ewert, Stephan D

FG Audiokommunikation

A fast and perceptively plausible method for synthesizing binaural room impulse responses (BRIR) is presented. The method is principally suited for application in dynamic and interactive evaluation environments (e. g., for hearing aid development), psychophysics with adaptively changing room reverberation, or simulation and computer games. In order to achieve a low computational cost, the proposed method is based on a hybrid approach. Using the image source model (ISM; Allen and Berkley [J.Acoust. Soc. Am. Vol. 66(4), 1979]), early reflections are computed in a geometrically exact way, taking into account source and listener positions as well as wall absorption and room geometry approximated by a “shoebox”. The ISM is restricted to a low order and the reverberant tail is generated by a feedback delay network (FDN; Jot and Chaigne [Proc. 90th AES Conv., 1991]), which offers the advantages of a low computational complexity on the one hand and an explicit control of the frequency dependent decay characteristics on the other hand. The FDN approach was extended, taking spatial room properties into account such as room dimensions and different absorption characteristics of the walls. Moreover, the listener orientation and position in the room is considered to achieve a realistic spatial reverberant field. Technical and subjective evaluations were performed by comparing measured and synthesized BRIRs for various rooms. Mostly, a high accuracy both for some common room acoustical parameters and subjective sound properties was found. In addition, an analysis will be presented of several methods to include room geometry in the FDN.