Speed of sound.

[Nieldo 0]

So is it just me thats noticed this? is it a bug?

Sound travels faster then bullets.

Your hear the gunshot before the bullet crack. At close range its not really a problem, you hear both pretty much isntantly. But at medium to long ranges you can hear the enemy shoot before the bullet gets anywhere near you, try it out, you can take cover before the bullet arrives because you hear the gunshot.

I have noticed that explosion sound effects do have speed, so there is a gap between seeing the explosion and hearing the explosion depending on how far away you were at the time. So I am hoping its just a bug which will be sorted out in no time :).

[armafreak 10]

Haven't noticed it, but will keep an ear out for it. On another note though, hiding behind a cabin and hearing the bullets strike wood and glass is absolutely priceless.

[galzohar 31]

And I thought the AI "just happened" to go prone right as I pulled the trigger... I guess they just heard the shot and actually "dodged" it due to the bullet flight time over long range and instant reactions.

[amfitamine 0]

I noticed the same thing. In the editor I placed soldiers about 300 meters away but when they started fireing in my direction I could hear the gunshot at the same time as I saw the mussle flash and only later i heared the supersonic bullet crack....I know BIS uses the speed of sound so I was wondering if any of you do not have this "problem"?

[galzohar 31]

They use speed of sound? If they do, I sure didn't notice it.

[joey 10]

The bullet cracks soon after it leaves the barrel. It cracks because its breaking the sound barrier, basically a sonic boom, and that only happens once when it leaves the barrel. so it would make sense that you heard the gun and then the crack...

the gun fire happens before the crack so you receive the gun sound first.

the crack isnt the sound of a bullet near you

or no? i could be wrong

Edited July 17, 2009 by joey

[Pyrodox 0]

The bullet cracks soon after it leaves the barrel. It cracks because its breaking the sound barrier, basically a sonic boom, and that only happens once when it leaves the barrel. so it would make sense that you heard the gun and then the crack...

then gun fire happens before the crack so you receive the gun sound first.

or no? i could be wrong

The "crack" is a sonic boom, which happens when something is travelling faster than the speed of sound, take for instance the bullet fired from an AK-74 which travels at about 900 m/s. Think of it as a "wake" of air being pushed out of the way of the object (the bullet) as it travels. You hear the sonic boom when the "wake" passes your ears. It will continue to create an audible "crack" for anyone it passes as long as it is travelling at supersonic speeds.

The "boom," or the muzzle report of the weapon, is travelling at the speed of sound, or about 340 m/s. And originating from the muzzle end of the weapon firing that projectile. You will hear this sound when it's reached your position.

Now, that bullet is travelling faster than the speed of sound, so, technicaly, the bullet will pass you, shortly after you will hear the "crack" then eventually the sound of the muzzle report will reach you.

It will take a longer time between the time at which you hear the "crack" and hearing the sound of the muzzle report the further away from the muzzle report you are. If you're say 1000m away from the person shooting at you, you will hear the "crack" approximately 1.11 seconds after they pull the trigger, and you will hear the "boom" about 2.94 seconds after they pull the trigger, or about 1.83 seconds after the "crack."

Edit: This is a "real" scenario. I'm not sure how it's handled in the game... But to make it realistic, it should go something like See Muzzle Flash -> Count to 1 -> Hear crack -> Continue counting to 3 -> Hear boom, providing you're standing 1000m from someone shooting an AK-74 at you.

Edited July 17, 2009 by Pyrodox

[Alex72 1]

The crack is indeed the bullet passing close to you. Since it flies fast enough and breaks the sound barrier you hear a snap/crack.

Its a sound made (played) when a bullet passes close to you and not calculated speed of sound formula - in ARMA2.

So far i havent notice the OP problem. Will test and see.

[dunedain 48]

I've noticed this too it seems that only explosions are delayed ..

[joey 10]

yep you guys are definitley right. I put someone at the end of teh airfield, and myself 750m away with the sniper scope, and you can hear the sound of the gun as soon as you see the muzzle flash. so thats off.

and thanks for the explaination pyrodox

[MarkB 10]

Sounds like a bug to me. I'm pretty sure they had this right in arma 1 or maybe I'm just misremembering.

[dayglow 2]

it has to be a bug because in A1 I can remember seeing smoke from gunshots before hearing them.

[osmo 0]

Reported.

http://dev-heaven.net/issues/show/2896

[Uziyahu--IDF 0]

Yes, I noticed this problem, too, but chalked it up to erroneously sub-sonic rounds. Didn't bother to consider that maybe the speed of sound in-game was too fast.

[Curry 10]

I posted this sound bug earlier in the vopsound thread in the mod section. I thought it was due to subsonic ammunition used by suppressed weapon but it seems that there is indeed something wrong with it.

At 2:22 you hear the shot before the bullet whizz.

Edited July 19, 2009 by Curry