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http://dx.doi.org/10.7776/ASK.2019.38.6.637

Analyses on limitations of binaural sound based on the first order Ambisonics for virtual reality audio  

Chang, Ji-Ho (Division of Physical Metrology, Korea Research Institute of Standards and Science)
Cho, Wan-Ho. (Division of Physical Metrology, Korea Research Institute of Standards and Science)
Publication Information
The Journal of the Acoustical Society of Korea / v.38, no.6, 2019 , pp. 637-650 More about this Journal
Abstract
This paper analyzes the limitations of binaural sound that is reproduced with headphones based on Ambisonics for Virtual Reality (VR) audio. VR audio can be provided with binaural sound that compensates head rotation of a listener. Ambisonics is widely used for recording and reproducing ambient sound fields around a listener in VR audio, and the First order Ambisonics (FOA) is still being used for VR audio because of its simplicity. However, the maximum frequencies with this order is too low to perfectly reproduce ear signals, and thus the binaural reproduction has inherent limitations in terms of spectrum and sound localization. This paper investigates these limitations by comparing the signals arrived at ear positions in the reference field and the reproduced field. An incidence wave is defined as a reference field, and reproduced over virtual loudspeakers. Frequency responses, inter-aural level differences, and inter-aural phase differences are compared. The results show, above the maximum cut off frequency in general, that the reproduced levels decrease, and the horizontal localization can be provided only around the forward direction.
Keywords
Binaural reproduction; First order Ambisonics; Virtual reality audio; Inter-aural level difference;
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