Multi-purpose sports stadiums have become an efficient and cost-effective solution for accommodating both speeches and musical performances. Particularly at universities, stadiums tend to be used not only for sporting events but also for ceremonies and other extracurricular activities. However, the expansive space of stadiums often results in a long reverberation time and thus causes problems with acoustics. In this study, we selected a university stadium to carry out a case study of a practical process for improving acoustics. We utilized field measurements to diagnose current performance and found that reverberation time was quite large. We performed a simulation with ODEON software and compared the results with the field measurements to verify the boundary conditions. Afterwards, we simulated design strategies based on both architectural acoustics and electroacoustics for evaluation. We found that a curve-shaped ceiling for MPP can reduce the reverberation time to approximately 2 seconds (unoccupied). Furthermore, various acoustic parameters, including SPL(A), C80, and STI, were improved via the electroacoustics process. Both the uniformity and the clarity of sound distribution were expected to be significantly improved for speeches by arranging the position and angle of the speakers.