Binaural audio engineering

Over the past decade, audio for virtual, augmented and mixed reality has become a critical part of delivering a truly immersive sound experience. With headphones being the most popular medium for audio consumption, binaural audio technology is one of the most convenient means to deliver accurate spatial audio. Head-related transfer functions (HRTF) are an integral component of binaural audio and determine the quality of the spatial audio experience. As human ears are highly unique, the HRTFs themselves are extremely idiosyncratic. Using non-individualized or generic HRTFs leads to front-back confusions, up-down elevations, in-head localization and tonal coloration that destroys the veracity of an immersive experience. In this chapter, the importance of personalized HRTFs and the state-of-the art techniques of HRTF personalization are discussed in great detail. These methods allow us to utilize and experience individualized HRTFs for VR/AR/MR, gaming, as well as spatial music applications. Another aspect of 3D audio perception especially in VR/AR applications is auditory-distance perception and the complex nature of the near-field HRTFs. This chapter also explains important cues for distance perception and the state-of-the-art techniques to model these distance-dependent HRTFs. Furthermore, state-of-the-art techniques in binaural reverberation estimation and equalization are explored in this chapter.