Perceptual Evaluation of Individualized Binaural Reproduction Using a Virtual Artificial Head

In binaural recordings, spatial information can be captured by using so-called artificial heads, which are replicas of real human heads with ear microphones and average anthropometric geometries. Mainly because of their non-individual character, such recordings often entail perceptual deficiencies (front-back confusion, internalization, etc.).Alternatively, individually measured head-related transfer functions (HRTFs) can be approximately synthesized using a microphone array in conjunction with a filter-and-sum beamformer (referred to as virtual artificial head, VAH). Its main advantage over traditional artificial heads is the possibility to subsequently adapt one recording to individual HRTFs in the reproduction stage by an appropriate modification of the directivity pattern of the VAH. Further advantages of the VAH include its smaller size and weight. The realization of a VAH as a planar microphone array with 24 microphones has been presented in previous studies. In this study binaural reproductions using the VAH, two traditional artificial heads, and individual HRTFs were perceptually evaluated in the horizontal plane with respect to the original free-field presentation. Evaluations were conducted for directions explicitly considered in the optimization of the VAH-filter coefficients but also for intermediate directions, which are assumed to be interpolated implicitly by the VAH. The ratings confirm the validity of the concept of synthesizing HRTFs using a VAH. It is found that theVAH-synthesis enables sufficiently good binaural reproductions that in general yield better perceptual ratings in comparison to traditional artificial heads for explicitly considered directions and approximately equivalent ratings for intermediate directions.