The authors added task-relevant sounds to a computer-mediated instructor in-the-loop virtual training for firefighter commanders in an attempt to raise the engagement and arousal of the users. Computer-mediated training for crew commanders should provide a sensory experience that is sufficiently intense to make the training viable and effective. In practice, sound is an important source of information for firefighters. During an evaluation of a soundless computer-mediated and instructor in-the-loop virtual training, both trainees and instructors frequently remarked that the lack of sound made the simulation less convincing and engaging. Research on entertainment games has shown that users may experience higher levels of presence, engagement, and arousal when sound is included in the simulations. The authors therefore hypothesized that the addition of task-relevant (informative) sounds to a virtual training would raise the engagement and arousal of the users, and the overall convincingness of the simulation. In this study, they included verisimilar and task-relevant sounds in an instructor in-the-loop computer-mediated firefighter training and assessed how these sounds affect user experience. In contrast to the common belief of trainees and instructors, the authors find that merely adding task-relevant sounds does not necessarily increase the engagement and arousal of the users. The authors conclude that the physical presence of (and verbal communication with) the instructor probably distracted from the simulation, and an integral sound design involving mediated communication with a remotely present instructor may be required to resolve this problem. (Contains 6 tables and 6 figures.)