Room Acoustics Computer Modeling: Study of the Effect of Source Directivity on Auralizations

Auralizations are very useful in the design of performing arts spaces, where auralization is the process of rendering audible the sound field in a space, in such a way as to simulate the binaural listening experience at a given position in the modeled space. One of the fundamental modeling inputs to create auralizations is the source directivity. Standard methods involve inputting the measured source directivity, calculating the impulse response and convolving it with a single channel anechoic recording. An initial study was conducted using this method and the results showed significant differences in reverberation time and clarity index when using a directional versus omni-directional source. Further research was conducted focusing on an alternative method of modeling source directivity that involves multi-channel anechoic recordings to create auralizations. Subjective tests were conducted comparing auralizations made with one, four and thirteen channels, with three different instrument types and subjects rated differences in realism. An analysis of variance (ANOVA) was carried out to determine the effect of the number of channels and instrument on realism. The primary result from this study was that subjects rated the auralizations made with an increasing number of channels as sounding more realistic, indicating that when more accurate source directivity information is used a more realistic auralization is possible.