Final Thesis

Perception of Spherical Harmonics Source Directivity Patterns in Rooms

Bachelor Thesis of Wolf, Gregor

Room acoustical measurements according to the international standard ISO 3382 are executed with the requirement of directivity of source and receiver to be omni-directional to ensure the comparability of standardized parameters. Due to this, directivity patterns of ordinary sources, like human speakers or instruments, are not respected in these measurements. For realistic auralization and precise room acoustical analysis the measurement of room impulse responses including the desired directivity is required. Due to practical considerations, every room impulse measurement is limited in terms of the spatial resolution in spherical harmonics. In this regard, the question of the human perception accuracy of the spatial resolution arises. Listening tests have proven, that differences between strongly directive sources and rather omni-directional sources are audible. The goal of this thesis is to evaluate the human perception accuracy of sound directivity pattern in rooms with consideration of the spatial resolution of the directivity patterns. For this task, defined directivity patterns of different spatial resolutions are simulated in different scene models with the objective to create signals for a listening test. Based on these simulations a listening test of the concluded sources and scenes is implemented and executed. With the data it is possible to evaluate how detailed the perception is and to analyse a possible threshold of audibility regarding the spatial resolution of the different sources. .