A spatial enhancement approach for binaural rendering of head-worn microphone arrays

This paper builds upon a recently proposed spatial enhancement approach, which has demonstrated im- provements in the perceived spatial accuracy of binaurally rendered signals using head-worn microphone arrays. The foundation of the approach is a parametric sound-field model, which assumes the existence of a single source and an isotropic diffuse component for each time-frequency index. The enhancement approach involves the post-processing of an initial estimate of the binaural signals, in order to obtain a refined esti- mate of binaural signals which more closely represent the inter-aural cues corresponding to the sound-field model. In this contribution, the enhancement approach has been implemented as an open-source framework, written in both the MATLAB and C programming languages, and as a real-time audio plug-in. The frame- work was also extended to offer direction-dependent gain control of sound sources relative to the listener, and a frequency-dependent control of the direct-to-diffuse balance, which are modifications that may find application within future augmented reality headsets and assistive hearing devices.publishedVersionNon peer reviewe

Diffuseness quantification of a reverberation chamber and its uncertainty with fine-resolution measurements

Insufficient diffuseness is the major cause of poor inter-laboratory reproducibility of acoustic measurements conducted in a reverberation chamber. Many previous studies have proposed new methods to quantify the diffuseness of a reverberation chamber more accurately, but there is no general agreement among researchers on the most reliable method. The number of measurement samples required for these diffuseness metrics is also unclear, even though it significantly impacts the robustness of the methods. This study, therefore, aims to quantify the diffuseness of a reverberation chamber by using the three widely used diffuseness metrics of spatial variation of sound pressure levels, the relative standard deviation of decay rates, and the degree of time-series fluctuations. The measurements were also carried out with fine resolution microphone positions and varied configurations of acoustic diffusers. With the measurement data, the minimum number of measurement samples to obtain an accurate diffuseness quantification was determined. It is shown that nine independent microphone positions are sufficient to provide the acceptable confidence interval for frequencies above 315 Hz for all three metrics. However, twenty or more microphone positions are needed for the same accuracy if lower frequencies are considered for the reverberation chamber under investigation