Subjective speech enhancement performance of a hearable with transparency and spatial frequency-weighted dereverberation

Abstract

Preserving natural binaural cues combined with directionality and robust dereverberation is crucial for successful sound enhancement via hearables. In this study, we subjectively evaluate the performance of a real-time hearable prototype that aims to enhance frontal speech and spatial cues in complex environments using a new dereverberation algorithm and acoustic transparency. Our real-time algorithm exploits the spatial frequency-weighted coherence-to-diffuse ratio estimated between the conchal microphones and produces directional binaural gains using a Wiener filter for sound enhancement. The new hearable system can be customized or adapted to a given environment for optimum performance in different frequency bands and preserves natural binaural cues for all individuals by symmetrical spatial filtering. We use the real-time prototype to evaluate the perceived speech intelligibility in noise by a Matrix framework for normal-hearing subjects in a reverberant classroom. We also use a multi-stimulus with hidden reference and anchor-like framework to evaluate the perceived speech quality and listening comfort of several stimuli simulated for HATS in the same environment. Results show that speech intelligibility and listening comfort in noise can be significantly improved for the real-time hearable using the new algorithm with optimized parameters compared with several state-of-the-art coherence-based algorithms implemented in a similar device.