What is the difference between high and low frequencies?
A. The frequency of a warning tone used in rating a siren’s Sound Pressure Level is critical in evaluating the performance of an outdoor warning siren, where the siren’s warning tones are expected to carry over great distances. Whelen siren systems are designed to optimize the production and projection of low frequency warning tones. It is documented that higher frequency tones attenuate (lose power) more over distance than low frequency tones. A warning siren capable of producing 124 dB at 100 feet with a 500hz warning tone will be more effective than a siren producing 124 dB at 100 feet using a 1,000hz warning tone. This factor should be considered in planning a warning system. Consider this example of the attenuation of higher frequency tones that is apparent in our everyday life……………… As you are standing out in your yard, your neighbor’s teenage son has the stereo in his car blasting as he is coming down the road toward your house. The earth seems to shake as the “boom,
