It's called a SOUND UPCUT. You write the scene then, for example...
SOUND UPCUT: A Chainsaw BUZZ.
CUT TO:
EXT.WOODSITE.DAY
A MAN weilds a supercharged chainsaw at a pair of unlucky tourists
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Online resources for film/TV studies may be found at ScreenSite
http://www.tcf.ua.edu/screensite