Scientific Article

Evaluation of head-tracked binaural auralizations of speech signals generated with a virtual artificial head in anechoic and classroom environments

¹ Institut für Hörtechnik und Audiologie, Jade Hochschule, Ofener Str. 16, 26121 Oldenburg, Germany
² Carl von Ossietzky University of Oldenburg, Department of Medical Physics and Acoustics, Carl-von-Ossietzky-Straße 11, 26129 Oldenburg, Germany
³ Akustik Technologie Göttingen, Bunsenstraße 9c, 37073 Göttingen, Germany
⁴ Cluster of Excellence “Hearing4all”

^* Corresponding author: matthias.blau@jade-hs.de

Received: 7 April 2021
Accepted: 21 June 2021

Abstract

In order to realize binaural auralizations with head tracking, BRIRs of individual listeners are needed for different head orientations. In this contribution, a filter-and-sum beamformer, referred to as virtual artificial head (VAH), was used to synthesize the BRIRs. To this end, room impulse responses were first measured with a VAH, using a planar microphone array with 24 microphones, for one fixed orientation, in an anechoic and a reverberant room. Then, individual spectral weights for 185 orientations of the listener’s head were calculated with different parameter sets. Parameters included the number and the direction of the sources considered in the calculation of spectral weights as well as the required minimum mean white noise gain (WNG_m). For both acoustical environments, the quality of the resulting synthesized BRIRs was assessed perceptually in head-tracked auralizations, in direct comparison to real loudspeaker playback in the room. Results showed that both rooms could be auralized with the VAH for speech signals in a perceptually convincing manner, by employing spectral weights calculated with 72 source directions from the horizontal plane. In addition, low resulting WNG_m values should be avoided. Furthermore, in the dynamic binaural auralization with speech signals in this study, individual BRIRs seemed to offer no advantage over non-individual BRIRs, confirming previous results that were obtained with simulated BRIRs.