Sound whistle effect

Two basic audible effects are produced by explosive and pyrotechnic devices a loud explosive noise (called a "report" or "salute" in the fireworks industry) and a whistling sound. 

Whistles, Pyrotechnic. US projectile ground-burst and booby-trap flash simulators precede their flash and expin with a whistling sound. The fact that certain compns whistle when compressed into a tube and ignited has been used in the fireworks industry for many years. The active substance most often used in pyrot whistles is gallic acid (3,4,5-trihydroxybenzoic acid). The K salts of benzoic acid of 2,4-dinitrophenol and of picric acid (2,4,6-trinitrophenol) and the Na salt of salicylic acid (o-hydroxybenzoic acid) are also effective. They are combined with K chlorate,... 

Although most pyrotechnic items produce some sound, for whistles and salutes sound is the primary effect. 

Two basic audible effects are produced by pyrotechnic devices a loud explosive noise and a whistling sound. In the terminology for noise effects, the sound effect itself is a report. The device that prodnces a report in the fireworks industry is a salute, and in the military it is a simulator. The typical composition used to produce a report, whether in civilian or military applications, is an oxidizer-metal mixture that is termed a flash powder. 

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