From the perspective of perceptual speech quality: The robustness of frequency bands to noise

TL;DR

This study investigates how different frequency bands of speech are affected by noise in terms of perceptual speech quality, revealing that mid-frequency regions are less robust and should be prioritized in quality improvement efforts.

Contribution

The paper introduces a novel MUSHRA-inspired method to evaluate the robustness of individual frequency bands to noise based on perceptual speech quality.

Findings

Mid-frequency regions are less robust to noise in perceptual quality.

Frequency band robustness varies significantly across the spectrum.

Results guide future speech quality enhancement to focus on mid-frequency regions.

Abstract

Speech quality is one of the main foci of speech-related research, where it is frequently studied with speech intelligibility, another essential measurement. Band-level perceptual speech intelligibility, however, has been studied frequently, whereas speech quality has not been thoroughly analyzed. In this paper, a Multiple Stimuli With Hidden Reference and Anchor (MUSHRA) inspired approach was proposed to study the individual robustness of frequency bands to noise with perceptual speech quality as the measure. Speech signals were filtered into thirty-two frequency bands with compromising real-world noise employed at different signal-to-noise ratios. Robustness to noise indices of individual frequency bands was calculated based on the human-rated perceptual quality scores assigned to the reconstructed noisy speech signals. Trends in the results suggest the mid-frequency region appeared less robust to noise in terms of perceptual speech quality. These findings suggest future research aiming at improving speech quality should pay more attention to the mid-frequency region of the speech signals accordingly.