I'm not sure if anything has it built in, but Thief: The Dark Project (in 1998) had sound propagation. There's some discussion about it here: https://www.ttlg.com/forums/showthread.php?t=151206. I wonder if you could query Unity's navmesh to calculate the distance, but that wouldn't work with, say, someone on the second floor hearing someone outside through the window.
Wouldn't you have an alternate navmesh for sounds with the appropriate "cost" heuristics based on how well sounds propagates through the mesh's material and across media?
This sounds like a great use of hardware accelerated raytracing. The problem itself is very similar. Sound attenuation can be modelled as transparency.
