A while ago I was hearing the persistent background noise coming from the windows of "Woof, woof, woof," a neighbor's dog. Then below that, or filtering around the edges of that noise, I could hear a deeper and more distant (at least 30 feet further) "Woof, woof, woof," as a second dog added his piece.
My own dog was sitting on the couch with me. And I glanced down and could tell she was hearing the same woofing noise, but it wasn't rousing her to reply in kind. It's one of those things that we get familiar with outside. She knows they're just woofing to be woofing and that her own joining in wouldn't accomplish anything.
But it was remarkable that she heard a closer noise, not animal, not human (probably was human), someone dragging something by, perhaps, and she woofed three times. I said shut up, she woofed again, I said shut up again, and after one more poorly phrased woof she shut up.