Subjective Audio Quality Testing, With Tasting and Car Driving as Parallel Tasks

This paper reports subjective test results of two different test sets: one without and one with a parallel task. The subjective listening tests were performed according to ITU-P.800 Recommendation. Regarding the parallel tasks, there were two categories: a parallel task that requires visual/motor coordination; and another that requires the use of taste perception. Specifically, in the first experiment, subjects were asked to drive a car simulator, while in the second they were asked to sort a variety of samples by taste. In both situations, the subjects performed the parallel task while assessing the audio quality. The results obtained in the experiments with a parallel task showed considerable differences from the standard P.800 test. Nevertheless, similar features were observed in the results of both parallel task tests. Based on those results, an objective estimator of speech quality assessed with a parallel task was developed, which was based on an enhanced ITU-T P.863 (POLQA) algorithm. The improved estimator provides a more accurate prediction of subjective tests with a parallel task than the original POLQA algorithm, as shown also in the results.