Each new stride in the development of industry and commerce has meant new demands on audio-signal equipment. Greater sound output with lower air consumption has been the continuing keynote for signal improvements in both the industrial and transportation fields. Leslie engineers have designed the most modern, complete line of air whistles available anywhere.RS Series Air Whistles, indicate Leslie-Supertyfon or specify: "Diaphragm type utilizing a single leaf stain-less steel diaphragm with molded-on silicone cushion ring."It is important to remember that the decibel (dB) is a logarithmic measure and when comparing the sound output of whistles, a direct numerical comparison cannot be made. A whistle with an output of 110 dB will sound about twice as loud (93% louder) as one with an output of 100 dB. Each 10 dB increase in output increases loudness by 93%, or approximately double. If frequency distribution, direction and air consumption remain constant, an increase of 10 dB in sound level would require the louder whistle to be twice as efficient at converting air energy into sound energy.

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