For the ceiling of a sports hall exposed to the elements, it is advisable to use acoustic materials that are not only effective in sound absorption but also durable and resistant to moisture and temperature changes. Materials such as fiberglass acoustic panels, mineral wool panels, or acoustic foam that is treated to be water-resistant would be suitable choices. These materials can withstand the environmental conditions of a semi-open sports hall while providing the necessary sound absorption to reduce noise levels and echo, ensuring a better acoustic environment for activities.