[acqq]

> if they're headed toward you, you'll not hear them (probably?)

Actually, you would not have much time to hear, but what you would hear (among the other effects) would be the sound “in reverse”(!)

https://physics.stackexchange.com/questions/14880/hearing-a-...

[rcxdude]

For a practical (if dangerous!) example, see supersonic rounds: if one is shot towards you, you hear the bullet whizzing by before you hear the gunshot.

[LgWoodenBadger]

Well, a supersonic round wouldn't whizz until it drops down to subsonic speeds.

You'd hear the crack of the round then the crack from the original shot.