The New York City Police Department on Monday announced the rollout of a gunfire tracking system known as ShotSpotter, technology that is aimed at combating gun violence.

The sound of gunfire is all too familiar in some neighborhoods, but now, the NYPD has started using technology called ShotSpotter to automatically pinpoint exactly where those bullets are coming from.

"The police are going to know instantly, so there's going to be a deterrent effect," said Mayor Bill de Blasio. "Some of the bad guys in this town are going to get the message that if they fire their weapon, the police will known instantly wherever there is a ShotSpotter apparatus."

Three hundred Shotspotter acoustic sensors have been placed across the Bronx and Brooklyn, covering 17 precincts and three housing police service areas.  

The sensors are linked to a computer, which determines the suspected location to within a few yards and notifies police.

Unlike other cities that use the ShotSpotter system, New York will link the audio system to its network of 8,000 NYPD cameras.

"It will cue up all the cameras within 500 feet of the ShotSpotter alert, and it will cue them up to right before the shots occurred, and it will play the audio of the shots with the video from the surrounding cameras all cued up to the same time," said Jessica Tisch, the NYPD's deputy commissioner of technology.

In fact, the department said within hours of the audio system going up in the Bronx Monday, it detected three shots fired on West Tremont Avenue. 

Police Commissioner William Bratton said historically, the Bronx and Brooklyn have had big problems with shootings. That's why those two boroughs are getting this technology first.

"Around the country, cities that have worked with this system indicate that on average, sometimes in excess of 75 percent of shots fired calls are never called into 911. Seventy-five percent," Bratton said. "That's a phenomenal underreporting of incidents of violence in any city."

Bratton said if the $1.5 million pilot program helps to reduce shootings in the two boroughs, it could be expanded citywide.