Use of binaural microphone7/29/2023 ![]() Ambisonics encoding and (binaural) decoding have been extensively researched in recent years ( Avni et al., 2013 Bernschütz, 2016 Zotter and Frank, 2019) and together form a well established spatial-audio format. Together with a set of HRTFs, the Ambisonics signals can then be decoded into binaural signals. Thereby, the number of microphones determines the highest SH order, and hence, the highest spatial resolution of the encoded sound field. This process is denoted as SH beamforming. The symmetric spherical body and the uniformly distributed microphones enable encoding the sound field into Ambisonics signals using the spherical harmonics (SH) transform and radial filtering. In particular, spherical microphone arrays (SMAs) are favorable array configurations for sound field capture and spatial reproduction. For instance, arbitrary head orientation can be synthesised and individual head-related transfer functions (HRTFs) can easily be integrated, while performing the signal processing in real-time ( Helmholz et al., 2019 McCormack and Politis, 2019), making microphone arrays flexible tools. In binaural reproduction, which is the focus of this work, the use of microphone arrays offers multiple advantages over dummy head recordings. Microphone arrays facilitate the spatial capture of a sound field and its subsequent reproduction, either over loudspeakers or binaurally for a single listener over headphones. With the growing number of virtual and augmented reality (AR/VR) applications, capture and immersive reproduction of sound scenes has become increasingly popular. ![]() Overall, BSM, and microphone-based stereo were rated the best for EMAs, and BFBR and microphone-based stereo for the glasses array. Results suggest that most approaches perform similarly to the Ambisonics rendering. The perceived differences were rated separately for the attributes timbre and spaciousness. ![]() In both listening experiments in which participants compared all approaches with a dummy head recording we applied non-head-tracked binaural synthesis, with sound sources only in the horizontal plane. In the EMA experiment we included a fourth-order Ambisonics rendering, while in the glasses array experiment we included a second-order Ambisonics rendering. Additionally, the perceptual evaluation included binaural Ambisonics renderings, which were based on measurements with spherical microphone arrays. The evaluation includes a microphone-based stereo approach (sAB stereo), a beamforming-based stereo approach (sXY stereo), beamforming-based binaural reproduction (BFBR), and BFBR with binaural signal matching (BSM). Using these two arrays, we conducted two listening experiments comparing four rendering methods based on acoustic scenes captured in different rooms 2. Second, we evaluated a microphone array with six microphones mounted on a pair of glasses. ![]() First, we evaluated equatorial microphone arrays (EMAs), where the microphones are distributed on an equatorial contour of a rigid, spherical 1. In this work, we present a comparison of methods for the binaural reproduction of sound fields captured with non-spherical microphone arrays. Therefore, the binaural reproduction of sound fields captured with arbitrarily shaped microphone arrays has become an important field of research. However, microphone arrays with a perfectly spherical body and uniformly distributed microphones are often impractical for the consumer sector, in which microphone arrays are generally mounted on mobile and wearable devices of arbitrary geometries. Microphone arrays consisting of sensors mounted on the surface of a rigid, spherical scatterer are popular tools for the capture and binaural reproduction of spatial sound scenes.
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