hear a pin drop, can
Be able to hear even the smallest noise because of the quiet, as in When he came onstage you could have heard a pin drop. This hyperbolic expression dates from the early 1800s.
The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.