This thesis takes place within the RASPUTIN project and focuses on the development, evaluation and use of immersive acoustic virtual reality simulation tools for the purpose of helping blind individuals prepare in-situ navigations in unfamiliar reverberant environments. A comparison of their techniques with those described in Blauert (1983), Shaw (1974), Mehrgardt and Mellert (1977), Middlebrooks, Makous, and Gree. The technique used by Wightman and Kistler (1989a) exemplifies a laboratory-based HRTF measurement procedure where accuracy and replicability of results were deemed crucial. Otherwise, the use of one HRTF set over another is a purely subjective judgment based on criteria other than localization performance. It is best when any single nonindividualized HRTF set is psychoacoustically validated using a 113 statistical sample of the intended user population, as shown in Chapter 2. The Convolvotron 3-D audio system (Wenzel, Wightman, and Foster, 1988) has used such sets particularly because elevation accuracy is affected negatively when listening through a bad localizers ears (see Wenzel, et al., 1988). If the localization ability of the person is relatively accurate or more accurate than average, it might be reasonable to use these HRTF measurements for other individuals. (One can sense a future 3-D sound system where the pinnae of various famous musicians are simulated.) A set of HRTFs from a good localizer (discussed in Chapter 2) could be used if the criterion were localization performance. But another approach might be to use the features of a person who has desirable HRTFs, based on some criteria. In 3-D sound applications intended for many users, we want might want to use HRTFs that represent the common features of a number of individuals. However, no phase data is included in the tables group delay simulation would need to be included in order to account for ITD. This paper gives HRTF magnitude data in numerical form for 43 frequencies between 0.2-12 kHz, the average of 12 studies representing 100 different subjects.

3d sound effects free download