Investigating the Impact of Audio Degradations on Users: Subjective vs. Objective Assessment Methods

Low-cost multimedia conferencing (MMC) is increasing in popularity, but it is often questioned whether the quality of the audio and video provided is usable. Traditionally, subjective methods have been employed to assess this. However, recent findings suggest that subjective ratings, which are cognitively mediated, may not reliably detect the impact of quality on users. To address this problem, we are taking physiological indicators of stress as a measure of user cost. In a study with 24 participants, physiological and subjective responses were taken to six types of audio degradation. Results show that the most physiologically stressful condition (audio recorded using a bad microphone) was not subjectively rated as poor. This discrepancy between subjective and physiological responses illustrates the peril of using subjective assessment alone, and supports our proposal for a three-tier approach to media quality assessment of task performance, user satisfaction and user cost.