Investigating the impact of stereo processing -- a study for extending the Open Dataset of Audio Quality (ODAQ)

TL;DR

This study extends the ODAQ audio quality dataset to include stereo processing effects, revealing how spatial characteristics and presentation context influence subjective audio quality assessments.

Contribution

It introduces a new dataset with stereo processing variations and analyzes their impact on subjective listening evaluations, highlighting the importance of spatial cues.

Findings

Listeners focus on timbral quality when spatial cues are consistent.

Direct comparison influences stereo perception disparities.

Mono anchor ratings remain stable across stereo conditions.

Abstract

In this paper, we present an initial study for extending Open Dataset of Audio Quality (ODAQ) towards the impact of stereo processing. Monaural artifacts from ODAQ were adapted in combinations with left-right (LR) and mid-side (MS) stereo processing, across stimuli including solo instruments, typical wide stereo mixes and and hard-panned mixes. Listening tests in different presentation context -- with and without direct comparison of MS and LR conditions -- were conducted to collect subjective data beyond monaural artifacts while also scrutinizing the listening test methodology. The ODAQ dataset is extended with new material along with subjective scores from 16 expert listeners. The listening test results show substantial influences of the stimuli's spatial characteristics as well as the presentation context. Notably, several significant disparities between LR and MS only occur when presented in direct comparison. The findings suggest that listeners primarily assess timbral impairments when spatial characteristics are consistent and focus on stereo image only when timbral quality is similar. The rating of an additional mono anchor was overall consistent across different stereo characteristics, averaging at 65 on the MUSHRA scale, further corroborating that listeners prioritize timbral over spatial impressions.