A WWII defense siren reached 184 dB, instantly deadly at the throat

Evidence

A huge, 50-horsepower siren-horn system was built and tested as part of a World War II civil defense system (see figure 7.20). On its first trial, it shook itself apart. The second version, built of steel, reached 184 dB at its throat—quite certainly instant death to anyone standing there. It was tested from the Manhattan Bridge in New York City with monitoring of decibel levels over a wide area; a map of the result is shown on the right. The compressor supplied 2500 cubic feet of air per minute at a pressure of five pounds per square inch. The siren contained six ports, with a total area of 21 square inches, opened and closed by a rotary chopper at a frequency of about 500 Hz. This siren was 20,000,000,000,000,000 times louder than the softest sound that can be heard, almost 300 watts of sound power per square centimeter near the throat. — Eric J. Heller, Why You Hear What You Hear- An…, 585

Categorization

• SHARE: Perfect for anyone fascinated by extreme acoustics or WWII engineering — a steel siren that delivered instant death at its throat and shook its wooden prototype apart.
• SEED: Article angle: the Manhattan Bridge megaphone — how civil defense weaponized everyday technology by scaling it to lethal intensities, and what that says about the line between tool and weapon.