Microphone placement in a binaural hearing manikin and its effects on IACC, reflectograms, and head-related transfer functions

A binaural hearing manikin was constructed and then tested by comparing its head-related transfer functions to those of a human subject. The manikin was used to record impulse responses in eight northeastern United States concert halls as part of the recent Concert Hall Research Group Study. The placement of the manikin’s 1/2-in. Bruel & Kjaer microphones varied between two locations: inside the head (truncating the auditory canal) and outside the head (20 mm from the canal opening). For most measurements, no statistically significant differences were found between octave band IACC values for the two microphone locations. The manikin’s head-related transfer functions were measured in an anechoic chamber using both microphone positions and 324 source positions. Comparisons of reflectograms and head-related transfer functions show that the manikin’s head and the human subject’s head affect sound in similar ways. [Work supported by the National Science Foundation and Concert Hall Research Group.]