Definition
Crackling is a sound-and-light effect produced by small grains of composition, often based on bismuth oxide or historically lead oxide, mixed with magnalium, that explode in a multitude of sharp micro-detonations with white or gold flashes. It is also called “dragon eggs” when the grains are larger and burst into petals, or simply crackling in catalogues. It appears as a pistil at the centre of a peony, as a full crown (crackling shell), as mine garniture, in cakes where each tube releases a crackling cloud, and in fountains. Crackling shells run from 75 to 200 mm; a 150 mm shell produces a cloud with its characteristic three- to four-second racket. Strongly felt by the audience, it provides the sonic contrast between two silent coloured tableaux.
In practice, for the display company
Crackling is loud: on a sensitive site (housing, animals) its use is limited or announced in the declaration file. PyroDesk flags the sound effect on the product sheet so it stands out in the timeline, and PyroSimulator renders it with its characteristic noise, letting you hear the balance between silent and crackling tableaux before the show.