As we mentioned in our guide earlier this week, sound is an important element in PlayerUnknown's Battlegrounds: it's key to listen very carefully for player footstep, car engines, and of course gunfire, especially when that gunfire is directed at you. Battlegrounds developer Bluehole posted an in-depth explanation of how gunshot sounds work in their battle royale shooter, and it's worth a listen (technically, a read) for anyone playing.

When someone shoots at you in Battlegrounds, you might hear three different sound effects, though what you hear, and when you hear it, depends on the distance between you and the person shooting, and how close their bullet comes to hitting you.

First, there's the sound of the gunshot, which has a propagation delay. "The propagation velocity is 340m/s so if a pistol is shot 340m away from the listener, he will see the muzzle flash first and hear the gunshot after 1 second," writes Marek, Battlegrounds' lead gun designer.

If you hear a 'whizz' sound that means a bullet has flown past you. You may also hear a crack sound, which is the "bullet bow shockwave." This occurs when the bullet, flying at supersonic speeds, passes you. The radius for the whizz and the crack are different, with the whizz radius being considerably bigger. In other words, if you hear a whizz and a crack, the bullet has passed very close to you, and if you only hear a whizz, it was close but not that close.

The image above demonstrates how that all works. An example is also given about the series of sights and sounds that occur when someone shoots at you from 1,000 meters using an AWM, which has a 900 meter-per-second muzzle velocity:

You see the muzzle flash After ~1 sec you hear the crack/whizz (assuming no air drag) After ~3 sec you hear the gunshot

The post continues:

"We blend between different sound samples based on distance (the maximum distance and attenuation characteristic is also affected by suppressor attachment). The close gunshot sounds louder and more clear than the distant one. In the current public build, all bullets generate a sound crack effect. We've changed this mechanic by adding a velocity check, so bullets travelling slower than speed of sound will not generate the crack effect but just whizz."

Paying close attention to these sound effects should give you a better idea of the distance someone is shooting from, how close they're getting to hitting you, and even what sort of weapon they're using.

Bluehole expects Battlegrounds to spend six months in Early Access, and as we reported earlier this week, the game is off to a strong start, earning over $11 million in its first weekend on Steam.