Development and Validation of a Sound Source for Near-field HRTF Measurements
* Presenting author
Abstract:
In near-field HRTF measurements, where the sound source that is used for emanating the excitation signal is placed in the close range (<1m) of the subject’s or the KEMAR’s head, care must be taken when deciding what kind of sound source to use. The ideal sound source should be infinitesimally small and omnidirectional, i.e. it should be a point source. When a large sound source is used, sound reflection and diffraction at its surface can introduce inaccuracies in the measured near-field HRTFs. However, an ideal point source is physically unachievable. Besides, the acoustical behavior of a small sound source would be degraded. In this paper, we introduce the development of a special sound source that resembles the behavior of an ideal point source with particular design considerations of its low-frequency feature. The frequency response and directivity pattern of this sound source are tested under free-field condition. Based on the analysis of the test results, the suitability of the sound source for usage in near-field HRTF measurements is discussed.