The sound of gunfire
 

When you can hear "gunfire in the distance" how far is that likely to be at maximum?

Obviously it will be louder closer to you but if you're approaching a battle at what distance are you likely to hear it, assuming that it only involves small arms, machineguns and grenade launchers?

Thanks for any guidance please can give me.

just some rough ideas...

Artillery can be heard as a distant rumble at about 20 miles or such, can easily be mistaken for thunder except for the regular pace of the firing.

Small arms can generally be heard at about 2-3 miles. You can almost always tell when a unit was on the firing range for example.

Of course wind and wind direction play major roles as well as terrain, even trees can block the sound of firing at a distance.

This will sound odd, but when tanks move you normally feel the vibes long before you hear the engines, and if the tank is fitted with a turbine, then the squealing of the tracks can be heard at about 300-400 meters. If the tank is fitted with a diesel engine, the key indicator for movement was to watch for the dark puffs of exhaust as the tank moved uphill, depending on the optics being used this could be spotted as much as a kilometer (using binos) or 2-3 kilometers (gunsights flipped to x10).

hope this helps!

This topic has come up before (and it is a worthy topic for discussion). I will have to have a look through the old threads.

Wasn't there a chart in Merc or SO for this? I think it was for silenced/suppressed shots vs. "natural" ones. If I get a chance, I'll look for it.

Thanks for the info. Very interesting!

I will have a search through the old threads as well.

Andy,

Something to keep in mind is what is firing, and the volume of fire.

In GURPS High-Tech the rule of thumb is a man can hear a .38 pistol shot 2 blocks away 50% of the time. This seems a little low, but perhaps that's the chance to recognise and identify a single shot, figure its range or direction. Kind of like you might not need to make a roll to see a mountain but would need one to identify specific or useful features.

If an entire unit is putting out a volume of fire and/or are using MGs, then yes, I think at you should allow an Observation/Hearing check from several kilometres away. Failure might indicate you hear gunfire but can't identify the weapons/range/direction.

Tony

Sound also travels further at night. Why, I don't know, but it does. (If anyone knows why, please post it.)

Paul: It's to do with the temperature layers in the air at different times of the day. The different temperatures create different air densities, and when these are "stacked right" you get a reflection effect that bends some of the sound waves back towards the ground (whereas in other conditions it will travel straight, or actually bend upwards into the sky). It's the same sort of idea as how the straw in your lemonade looks like it has a bend in it.

This is also the reason they typically do blasting and demolitions at certain times of the day, so that the sound will not be louder at ground level compared to other times.

And yes, I used to teach physics. :)

Exactly what i thought ...

here tis

That's the one I couldn't find a few days ago. Where was it? I think in Merc 2000, but what page?

It could be as simple as the ambient temperature being lower at night. Sound travels better in denser air, and cooler air is more dense than warmer air.

Also, there is often less noise at night so short, sharp sounds would tend to be more noticeable.

Your right. Merc 2000. Page 84 - 86 deals with sound. Some more attached.

Over distance there are potential weird quirks as well. There was a Union Civil War general (Sheridan, I think) who got a lot of criticism for not being faster to respond to a portion of his command being in contact at a distance where the noise should have been obvious. It was later determined his headquarters was sitting in some sort of odd pocket where the terrain masked the sound of artillery and firing completely.

all too true, its amazing the effect that a few hundred feet of trees and brush have on sound, especially something like gunfire or explosions. And toss in a small hill......

...or a small valley....
Just about anything and everything will have some kind of effect on how far noise will travel.

And in a city, canyon, or mountains, you might hear the shots, but have no idea where they are coming from.

Something I am reminded of, every New Year's Eve and July 4th, around my house. Some of them are probably firecrackers, some of them are definitely not. I have some 9mm souvenirs somewhere in the framework to prove it.

Having spent a new year's eve in Vallejo California I can say that trying to ID what is being shot into the air is rather unnearving.

"Pistol, pistol, shotgun, revolver, pistol, AK-47, pistol shotgun, shotgun..."