It's not something you really expect unless you knew about it in advance. It's more spectacular at night. A stream of red tracers drawing a line in the night sky for two or three seconds. Then you hear it. "BRRRRRRRRRRRRRRTTT." The tracers disappear, the point where they stopped lit up with small white explosions, like far off firecrackers. Sounds like it, too. "BRAKACRAKLECRAKCRAKLE."
It's a point-defense system for the base, a radar-guided minigun shooting at incoming mortar rounds. It happens far more frequently, more frequently than the frequent "hey, indirect fire happened but it's cool now" announcements over the loudspeakers. You wonder if they test the system a lot, if the system really does shoot down that many incoming rounds, or if there are a lot of exploded bird parts all over the area. At any rate, you never see the kind of explosion you'd expect if those rounds did hit a mortar shell.
Even more frequent is the sound of jet engines. This is, after all, an airbase. But not just any jet engines: This base has F-16s. Sure, you lived on an Air Force Base before and you've heard fighters take off. But not like this. Stateside, jets take off under full military power. Over here they take off at full afterburner. It sounds like the engines are literally tearing the fabric of reality. The loudest fabric tearing sound you'll ever hear.
It happens at all hours of the day, usually in pairs. It shakes your can, as you're only a couple kilometers from the flight line. The sound is inescapable, audible even through the sound-isolating earbuds you plugged into your laptop. It rouses you from your sleep. Sometimes, when you're unfortunate enough to be outside and way from the t-wall barriers, it pummels your ears.
You never get tired of that sound.