Auralization software for the evaluation of the results obtained by a pyramid tracing code: Results of subjective listening tests

This paper deals with the evaluation of the numerical previsions obtained by a newly developed Pyramid Tracing computer program, named Ramsete [1,2,3,4]: as the results are in form of impulse responses, these can be compared with experimental impulse response measurements taken in the actual spaces that are being numerically modelled [5]. Another way to compare the numerical results with the experimental ones is by listening to musical pieces, spoken text, or other signals convoluted with the (pressure) impulse responses. This is possible if the energy impulse responses computed by Ramsete are converted in pressure impulse responses, by an original algorithm described here. This is the core of a new Auralization program, named Aurora. Aurora is also equipped with a fast convolution software [6], running on a PC and not requiring any DSP board, that can process standard WAV files of unlimited length with binaural impulse responses up to 200000 taps (these can be both experimental or numerical). A standard 16 bit low cost PC audio board and high quality headphones are then used to submit the convoluted signals to judging panels (actually these are students of Parma’s University), that have to fill up a questionnaire. With proper statistical analysis of the questionnaires, the validity of the simulation software has been assessed: although part of the subjects were still able to distinguish between signals convoluted with experimental an