HRTF measurement on KEMAR manikin

Presenting sounds to humans in virtual environments requires convolving the free field signals with a head related transfer function (HRTF), which is a frequency response describing the filtering effects of the pinna, head and torso of a human. Sets of HRTFs are usually measured on the dummy head or human subjects at different directions in an anechoic room. This paper describes the details of an experimental HRTF measurement procedure with emphasis on the design of the test signal and the post-processing to extract HRTFs. We construct a pre-emphasized logarithmic sweep as the excitation signal which separates the nonlinear and time variant distortions from the main desired response. For the received raw data, a series of signal processing techniques are applied to determine the timing offset when the head response begins, to mitigate room reverberation, and to equalize the HRTF measurements. One of the goals of this paper is to provide details of the experimental setup. Also, we intend to publish our processed measurements in the form of a HRTF data base as a resource for the acoustic community.