system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why does thunder sound like a crack close up but a roll from far away?
gpt
The up-close crack is direct from the lightning epicenter to you.  The roll has bounced off a few things along the way.

Possibly helpful analogy.  Imagine dropping a pebble into a swimming pool and watching the ripples.  When the ripples hit the side of the pool, they get reflected, and intermix with themselves.

Now imagine that the pebble is the lightning strike that created the thunderclap.  If you're in a place where you hear the unreflected clap, what you hear is pretty simple.  If your vantage is somewhere so you don't hear it till it's reflected (by, say, the ground), then what you hear is more complicated and mixed up.