system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How can our ears differentiate between sounds that are really far away and sounds that are close, but quiet?
gpt
Sound that is far away has a few characteristics that close sound does not:

1. the sound will have bounced off of things and will arrive at your ear through multiple avenues.  The close sound will not have done this.  We can discern this difference.

2. Certain undertones and overtones will have been lost traveling the distance - they'll be weaker, or won't survive the medium through which they travel at the same levels.  

The TL;DR: on this is essentially that they sound different!