Implementation and Comparative Analysis of Head-Related and Binaural Room Impulse Response in a Mid-Side Decomposition

Sammanfattning: This thesis aimed to clarify the essential factors involved in externalising audio over headphones. Extensive research was conducted, examining binaural cues and the latest advancements in the field. A novel approach was proposed, which applied HRIRs and BRIRs on a Mid-Side decomposition. The objective was to enhance frontal externalization while increasing control over centre-panned and side-panned elements. The proposed method underwent rigorous testing in various setups, accompanied by objective and subjective evaluations. The objective measures were then correlated with the findings from the subjective evaluations. Interaural coherence analysis revealed that the BRIR exhibited lower overall coherence values than the HRIR. This was anticipated, considering BRIRs capture room acoustics that impact sound perception compared to anechoic conditions. Introducing simple room acoustics, such as early reflections and reverberation tails, significantly reduces the coherence in higher frequencies for HRIR. Connecting these findings to the conducted listening test, it is observed that lower IC generally corresponded to a wider audio configuration. However, assessing frontal externalization proved challenging. Among the tested configurations, the two BRIR models achieved the most width, with the unsmoothed version performing slightly better. This suggests a tradeoff between externalization and colouration, as the smoothed BRIR model excelled in spectral colouration and preference. For the HRIR, adding room acoustics slightly increased the width. It received lower ratings regarding spectral colouration and was not preferred over the HRIR model without room acoustics. This reinforces the significance of preserving the original spectral characteristics.