A Great Pyrenees is very quiet until it has good reason to bark, and then you’d think the world was coming to an end. Big dogs, almost like a Newf or St. Bernard, and somewhat similar temperament, but solid white. Originally bred to guard livestock.
I grew up with an English Mastiff. She would bark at the coyotes howling a few miles over. You could hear the echoes for a while after she finished. But is was very rare. She wouldn't bark to warn you--she'd take care of the problem her own self.
My Irish Wolfhound was the same way. When he barked, there was no mistaking which dog was barking and there was always something there. He didn't bark at ghosts. His miniture poodle-mix buddy on the other hand barked at everything. We ignored him unless the big guy joined in.