Efficient HRTF synthesis using an interaural transfer function model

We propose an alternative method for binaural synthesis using the ratio of the HRTFs at the two ears, the interaural transfer function (ITF), for deriving the response at the contralateral ear from the ipsilateral one. This technique allows an optimal binaural synthesis if an accurate ITF model is used but a computationally more efficient binaural synthesis can also be obtained by simplifying the ITF filter used for the contralateral channel processing, which is perceptually less critical than the ipsilateral response. Different filter designs and filter orders are investigated for both speech and wide-band signals. Subjective tests are carried out to investigate the perceptual differences introduced by this ITF model. The results indicate that an ITF filter can be of considerably lower complexity when compared to the ipsilateral filter, thus allowing for computational savings without significant perceptual degradation.