My game suffers functionally unplayable frame drops when the renderer tries to calculate sound in proximity to a fairly crowded pen of neutral creatures, very likely because it's trying to render sound for all the entities. This might be a lot of them, this is hardly unrealistic for most worlds and most servers to have that many in one place. Turning off rendering of sound physics fixed the frame drops immediately.

This isn't so much a "bug" as it is the renderer working as intended but lacking optimization for scenarios wherein which many mobs are present somewhere. I would rather avoid having to turn off friendly mob sounds in my game because of this one place.

This is simply a performance problem, there isn't really anything we can do to optimize entity sound specifically. This should get better as we make more and more performance improvements. In the meantime, version 0.5.2 has a 6x performance improvement over the previous version.