Influence of Microphone Placement on the Measurement of Head-Related Transfer Functions

Influence of different placements of recording microphones on the measurement of head-related transfer functions (HRTFs) was investigated using measured HRTFs from the KEMAR artificial head, by means of objective and perceptual-motivated criterion. Results show that the microphone displacement leads to poor repeatability of HRTF measurements, especially at the characteristic notch in the magnitude of HRTFs ipsilateral to sound source with a maximum deviation reaching 30 dB. However, those large deviations can be greatly reduced with perceptual smoothing, and the mean deviation across the entire audible frequency range is less than 3 dB. Therefore, the consistency of microphone placement is an important factor guaranteeing measurement quality for HRTFs.