The crackle medium is applied over a coat of paint (there are also crackle products that contain color) and the crackle medium allows that base coat to show through in places, giving a rough, aged appearance.
If stenciling is the most basic type of decorative painting, one step up would be the faux painting techniques popularly done on walls, such as sponge painting, ragging, and distressed or crackle glazing.
There was a crackle on the line.
A crackle on the radio interrupted any response.
Her room was made of black stone and quiet with no sounds except the crackle of fire.