Wwise SDK

The total length of a path composed of a sequence of segments (or rays) cannot exceed the defined maximum path length. High values compute longer paths but increase the CPU cost. Each individual sound is also affected by its maximum attenuation distance, specified in the Authoring tool. Reflection or diffraction paths, calculated inside Spatial Audio, will never exceed a sound's maximum attenuation distance. Note, however, that attenuation is considered infinite if the furthest point is above the audibility threshold.

AkSpatialAudio.h の 73 行目に定義があります。