[Nexus]

I love answering my own questions:

This site says that not only was the artillery noise from Gettysburg heard in Pittsburgh, but it sounded like rolling thunder in Baltimore!

http://www.travelbrains.com/Destinations/Gettysburg/Gettysburg_hp.html

[VadeRetro]

Sound sometimes bounces off of atmospheric layers. Sometimes a loud sound is heard 100 miles from the origin but not at points between, the angle being unfavorable for good bounce effects.

[brazzaville]

Good evening.
"I love answering my own questions:"

Hopefully you get an honest answer that way.

Michael Frazier