Evaluation of Binaural Renderers: Externalization

Binaural renderers can be used to reproduce dynamic spatial audio over headphones and deliver immersive audio content. Six commercially available binaural renderers with different rendering methodologies were evaluated in a multi-phase subjective study. This paper presents and discusses the testing methodology, evaluation criteria, and main findings of the externalization, front/back discrimination and up/down discrimination tasks that are part of the first phase. Statistical analysis over a large number of subjects revealed that the choice of renderer has a significant effect on all three dependent measures. Further, ratings of perceived externalization for the renderers were found to be content-specific, while renderer reversal rates were much more robust to different stimuli.