The ceiling may have wood reflectors, or a few boxes filled with environmentally-safe fiberglass material may hang from the ceiling to stop any ringing caused by the ceiling.

• 天花板上可能会有木制反射面，或者有一些用环保玻璃纤维填充的小盒子悬挂在天花板上以防止由于天花板带来的任何响声。