The saddest noise can be many different things, depending on the situation. Some of the most commonly accepted saddest noises include the sound of a baby crying, the sound of a loved ones last breath, the sound of silence in a place that was once alive with activity, and the sound of a person who is struggling to say goodbye. It can also be less tangible sounds, such as a heart breaking into a million pieces, an anguished plea for help, or a tear rolling down someones face.