In the past, before and after missile attacks, Israeli civil defense sirens would first send out distinctive variable warning tones, meaning “take cover,” and follow them with a steady, single tone to indicate “all-clear.” But all-clear tones have not been used during recent Israel air raids for the somewhat ironic purpose of “avoiding needless confusion.” Also a bit ironic, most sirens in use in Israel were manufactured in Germany. And they are loud. The sound volume of the “supercharged” HLS F-71 pneumatic alarms used throughout Jerusalem and made by Hörmann gmbH, for example, are rated at 132 decibels, considered slightly louder than an aircraft jet engine at takeoff.
In less technical terms, they can knock your socks off.[Read more…]
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