Since the implementation of Frequency Module, sound is dimension-dependent, probably for sake of "scientific correctness" (hi Kethrian!). For example, on the overworld, sound is 100% audible; in a space station dimension, sound is almost impossible to be heard, then you need to put a Frequency Module on in order to be able to hear the sounds.
Once we are talking about "scientific correctness", sound should be 100% audible inside air-filled rooms and oxygen bubbles.
Once we are talking about "scientific correctness", sound should be 100% audible inside air-filled rooms and oxygen bubbles.