Investigation of Phase Distortion on Perceived Speech Quality for Hearing-impaired Listeners

TL;DR

This study examines how phase distortion affects perceived speech quality for hearing-impaired and normal-hearing listeners, revealing negative impacts and the correlation of objective metrics with subjective ratings.

Contribution

It provides new insights into the effects of phase distortion on speech quality for hearing-impaired listeners, an area less explored compared to normal-hearing listeners.

Findings

Phase distortion negatively impacts perceived speech quality for both groups.

PESQ correlates more closely with human ratings than HASQI.

Hearing-impaired listeners are similarly affected by phase distortion as normal-hearing listeners.

Abstract

Phase serves as a critical component of speech that influences the quality and intelligibility. Current speech enhancement algorithms are beginning to address phase distortions, but the algorithms focus on normal-hearing (NH) listeners. It is not clear whether phase enhancement is beneficial for hearing-impaired (HI) listeners. We investigated the influence of phase distortion on speech quality through a listening study, in which NH and HI listeners provided speech-quality ratings using the MUSHRA procedure. In one set of conditions, the speech was mixed with babble noise at 4 different signal-to-noise ratios (SNRs) from -5 to 10 dB. In another set of conditions, the SNR was fixed at 10 dB and the noisy speech was presented in a simulated reverberant room with T60s ranging from 100 to 1000 ms. The speech level was kept at 65 dB SPL for NH listeners and amplification was applied for HI listeners to ensure audibility. Ideal ratio masking (IRM) was used to simulate speech enhancement. Two objective metrics (i.e., PESQ and HASQI) were utilized to compare subjective and objective ratings. Results indicate that phase distortion has a negative impact on perceived quality for both groups and PESQ is more closely correlated with human ratings.