Expect to hear the sound of gunshots between 5:30 and 11:30 p.m.

Denver police will shoot bullets into a special trap that absorbs the energy of the ammo in order to calibrate its gunshot detection system Wednesday evening and into the night.

The Denver Police Department performs periodic tests of ShotSpotter tech, which pinpoints the location of gunfire so that 911 dispatchers know where to send officers in a live emergency.

“The live-gunfire tests will consist of a sequence of gunshots followed by validation of sound detection by the system,” DPD said in a statement. “During the tests, a bullet trap will be used to ensure public safety — no bullets will be fired into the air or ground, and there is no danger to the public.”

Expect to hear the sound of gunshots between 5:30 and 11:30 p.m.