Glendale, AZ is an interesting suburb on the Westside of the Valley. After a 6 month stint in Glendale, I don’t think I’d move back.

ShotSpotter is acoustic surveillance technology that the city employs to detect gunshots.

The system relies on an acoustics-based, GPS-equipped system that automatically locates the origin of the shot and notifies authorities. A series of acoustic sensors picks up the sound waves of a muzzle blast that radiate outward from the barrel in all directions.

Acoustic Triangulation
ShotSpotter uses 10 to 12 sensors spaced evenly throughout each square-mile section of the city it’s covering, and each sensor is capable of hearing the sound of gunfire within a 2-mile radius.

1. A shot is fired somewhere in the city. Sensor 1 picks up the sound of the shot.
2. One second later, a second sensor picks up the sound waves of a gunshot. If sound in this city travels at about 0.21 miles per second, we now know that the shot was fired approximately one-fifth of a mile farther away from Sensor 2 than from Sensor 1.
3. To figure out which of these two points is the location from which the shot was fired, we need to find a third sensor that picked up the sound of the shot. A third sensor, located to the south of Sensors 1 and 2, picked up the sound waves a half-second after Sensor 2 detected them. This would put the origin of the sound about one-tenth of a mile farther from Sensor 3 than from Sensor 2.

Source: Howstuffworks