Mammoth Siren Tested The world’s largest siren, which reportedly equals the noise made by 2,000 symphony orchestras, is now being tested in a remote mountain area near Newhall, Cal., it was announced by University of California, at Los Angeles recently. UCLA disclosed the 90-foot noisemaker is operated by air fanned from two big Rolls Royce engines. It’s loud enough to cause permanent damage to unprotected ears and scientists at the site wear special ear-plugs. The siren is being tested for the Navy, and some aspects of the research are secret. Thus far, the UCLA report said, the machine has demonstrated that sound waves of high intensity take on the aspects of shock waves after a short time.