A CATALOG OF SOUNDS
The most resonant sounds result from the perfectly regular rhythms of stars known as cepheid variables. Cepheid variables alternately expand and contract to as much as 30 percent of their normal size. These regular changes in size are accompanied by changes in brightness, temperature, and spectral type.
The most irregular rhythms belong to the complex sound waves which form so-called white noise. By definition, noise contains waves of different frequencies, any of which has no multiple or submultiple relationship to the others.
The most characteristic sounds are those which are uniquely expressive or familiar. Normally, an expressive musical pattern or phrase is underlined by psychological tensions which directly confront the emotions of the listener. The familiar childhood ridicule "Nah, Nah-Nah, Nah, Nah" or the most sublime melodies of Schubert or Mozart are extreme examples. Individual sounds with deep psychological associations will also create a strong impression, such as the sound of a crying baby, or the roar of a wild animal.
The least characteristic sounds are those which are void of emotional or intellectual tensions, or sounds that fail to engage our attention at all. These sounds may be physically soothing, such as the constant lapping of ocean waves on the beach, flat monotonic utterances of speech, or commercial ambient sounds.
The most intense sounds are shock waves. Shock waves travel at supersonic speeds and are produced by small disturbances such as the bursting of a balloon or small explosion, or by large disturbances such as a flash of lightning causing a thunderous sound, a foreign object such as an airship or meteorite traveling at supersonic speed, or by various chemical or nuclear explosions. The most intense sounds are standing shock waves, produced by the rotation of stars or galaxies, and by stellar explosions including supernovas.