Binaural detection thresholds and audio quality of speech and music signals in complex acoustic environments

Every-day acoustical environments are often complex, typically comprising one attended target sound in the presence of interfering sounds (e.g., disturbing conversations) and reverberation. Here we assessed binaural detection thresholds and (supra-threshold) binaural audio quality ratings of four distortions types: spectral ripples, non-linear saturation, intensity and spatial modifications applied to speech, guitar, and noise targets in such complex acoustic environments (CAEs). The target and (up to) two masker sounds were either co-located as if contained in a common audio stream, or were spatially separated as if originating from different sound sources. The amount of reverberation was systematically varied. Masker and reverberation had a significant effect on the distortion-detection thresholds of speech signals. Quality ratings were affected by reverberation, whereas the effect of maskers depended on the distortion. The results suggest that detection thresholds and quality ratings for distorted speech in anechoic conditions are also valid for rooms with mild reverberation, but not for moderate reverberation. Furthermore, for spectral ripples, a significant relationship between the listeners’ individual detection thresholds and quality ratings was found. The current results provide baseline data for detection thresholds and audio quality ratings of different distortions of a target sound in CAEs, supporting the future development of binaural auditory models.

日常声学环境往往较为复杂，通常包含一个需重点关注的目标声，同时伴有干扰声（例如令人分心的交谈声）与混响。本研究针对此类复杂声学环境（complex acoustic environments, CAEs），评估了四类失真——频谱波纹（spectral ripples）、非线性饱和（non-linear saturation）、强度修正与空间修正——分别作用于语音、吉他及噪声目标时的双耳检测阈值（binaural detection thresholds），以及对应的阈上（supra-threshold）双耳音频质量评分。目标声与最多两路掩蔽声既可处于共位状态（仿佛同属一个音频流），也可空间分离（仿佛源自不同声源）。研究中系统地调控了混响量。结果表明，掩蔽声与混响对语音信号的失真检测阈值具有显著影响；音频质量评分受混响影响，而掩蔽声的影响效果则取决于失真类型。研究结果显示，消声环境（anechoic conditions）中失真语音的检测阈值与质量评分标准，同样适用于混响较弱的房间，但不适用于混响中等的场景。此外，针对频谱波纹失真，研究发现听者个体的检测阈值与质量评分之间存在显著关联。本研究结果为复杂声学环境中目标声经各类失真处理后的检测阈值与音频质量评分提供了基准数据，可为双耳听觉模型的后续研发提供支撑。