Characterization of the head-related transfer function using chirp and maximum length sequence excitation signals

摘要

Both chirp (or sweep) and maximum length sequence (MLS) excitation signals are used to obtain measurements of the head-related transfer function (HRTF) for the Knowles electronic manikin for acoustic research (KEMAR), resulting in remarkably low relative error between the two measurement methods. Due to the low relative error, it is asserted that applying both methods in experiments involving system characterization can be used to confirm the accuracy of individual measurements and reduce the likelihood that erroneous measurements go unnoticed.An MLS burst-augmented excitation signal is presented to compensate for unpredictable delay added in sound-acquisition software that lacks the capability of synchronized record/playback.The HRTF measurements obtained with an external probe microphone are compared with those obtained with the standard in-ear microphones that the KEMAR is equipped with, to reveal that care should be taken to select a probe microphone that has a low susceptibility to multipath interference.An experiment is performed to investigate the feasibility of using two pre-filtered chirp responses to obtain the relative transfer function between the two locations of measurement.