acoustic shadow

An acoustic shadow is an area through which sound waves fail to propagate, due to topographical obstructions or disruption of the waves via phenomena such as wind currents. As one website refers to it, "an acoustic shadow is to sound what a mirage is to light".

1. The building created an acoustic shadow, making it difficult to hear the speaker.
   建筑物形成了声影，使得听众难以听到演讲者的声音。
2. In medical imaging, an acoustic shadow can indicate the presence of a solid object.
   在医学成像中，声影可能表明有固体物体的存在。