The objective of this paper is to introduce an application of multi-sensory cognitive learning theory into the development of a multimedia tutorial for Item Response Theory. The cognitive multimedia theory suggests that the visual and auditory material should be presented simultaneously to reinforce the retention of learned materials. A computer-assisted module is carefully designed based upon the preceding theory and also an experiment was conducted to examine the effect of audio types (human audio, computer audio, and no audio) on learner performance measured by an objective test. It was found that while there is no significant performance gap between the human audio and the no audio group, the two groups substantively outperform the computer audio group. A plausible explanation is that un-natural audio requires additional cognitive power to process the information and thus this distraction affects the performance.