The auralization with the BRIRs directly measured with a dummy head can still be regarded as the ground truth ( Brinkmann et al., 2014 Lindau, 2014). Such BRIRs can either be obtained with impulse response measurements using a dummy head ( Stade et al., 2012), calculated from spherical microphone array (SMA) captures ( Bernschütz, 2016), or generated by parametric synthesis ( Mccormack et al., 2020 Merimaa and Pulkki, 2004 Pulkki, 2007 Tervo et al., 2013) or simulation ( Brinkmann et al., 2019 Savioja and Svensson, 2015 Vorländer, 2008). The binaural auralization of virtual acoustic environments can be achieved by convolution with binaural room impulse responses (BRIRs). Furthermore, significantly lower orders are required for the late parts with N = 4–5 for the early reflections and reverberation of the dummy head BRIRs but N = 12–13 for the early reflections and N = 6–9 for the reverberation of the SMA BRIRs. The results indicate that for direct sound, N = 9–13 is required for the dummy head BRIRs, but significantly higher orders of N = 17–20 are required for the SMA BRIRs. This paper presents two listening experiments to determine the minimum spatial order for the direct sound, early reflections, and reverberation of the dummy head or SMA measurements required to generate the horizontally head-tracked binaural synthesis perceptually indistinguishable from a high-resolution reference. For both of the methods, the spatial order N of the underlying sampling grid influences the reproduction quality. The real-world SMAs, on the other hand, have a limited number of microphones, resulting in spatial undersampling artifacts. Because the dense dummy head measurements require enormous effort, alternatively sparse measurements can be performed and then interpolated in the spherical harmonics domain. Such BRIRs can either be measured with a dummy head or calculated from the spherical microphone array (SMA) data. Dynamic binaural synthesis requires binaural room impulse responses (BRIRs) for each head orientation of the listener.

Binaural recording database