 Gunshot Directionality, How to pin point sound? |
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 Jan 17 2007, 04:55 AM
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#1
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Moving Target  Group: Members Posts: 116 Joined: 5-May 02 From: Sydney Sprawl Member No.: 2,687  |
Ok, imagine this situation:
Runners are strolling down the street. It is fairly quiet and they are in a built up area. A gun shot rings out. How difficult would it be for them to work out the direction the shooter is in by listening? Note that it isn't necessarily them that is being shot at. I would imagine it would be rather difficult as the sound would echo around the hard surfaces of the surrounding buildings and street. I have a reasonable knowledge of how sound works and how you work out directionality (I work as an audio technician) but don't really know how it would work with a gun shot as I am not familiar with the sound. So, I would like to see some discussion on how this would work in real life and also how you would handle it with the SR rules. Ideas? -Strobe |
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Jan 17 2007, 04:59 AM
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#2
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Creating a god with his own hands Group: Members Posts: 1,405 Joined: 30-September 02 From: 0:0:0:0:0:0:0:1 Member No.: 3,364 |
for a human it would be a bit difficult. even more so if the person is smart and uses a sound suppressor.
for a sensor system it would be cake. two or more directional audio sensors. after that it's all trig. |
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Jan 17 2007, 05:04 AM
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#3
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Moving Target Group: Members Posts: 116 Joined: 5-May 02 From: Sydney Sprawl Member No.: 2,687 |
I'm looking for the human angle here. Also you can assume they aren't using suppression or a silencer. I seem to remember that Lone Star were trained to listen out for gun shots from their standard issue weapons to provide backup. How would they be able to do that without knowing where the shot was fired? At least a behind or in front type directionality. Generally we humans have trouble playing the direction of low frequency noise. What sort of frequency does a gun shot produce? -Strobe |
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Jan 17 2007, 05:08 AM
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#4
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Shooting Target Group: Members Posts: 1,838 Joined: 1-September 05 Member No.: 7,669 |
Since damn near everyone carries a commlink, you should just get an audio pickup with the needed hardware. Network with a few of your buddies and you can triangulate in on it in no time. Sniping is dead.
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Jan 17 2007, 05:10 AM
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#5
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Moving Target Group: Members Posts: 745 Joined: 2-January 07 From: Los Angeles, CA Member No.: 10,510 |
I think the runner's experience and instincts would count much more than a "reasonable knowledge of how sound works and how to work out directionality". Fortunately, the rules already take this into account very well with the Intuition attribute. So I'd mark it up as Perception + Intuition. One hit is all that's needed to figure general direction. 2 hits tells you what location the shot came from. 3 hits means you actually probably saw it by chance and you know exactly who it was and who they were aiming at and what kind of weapon it was. The guy with the highest total Perception + Intuition is the primary roller who will determine success or failure, but the others could roll their Perception + Intuition to provide helping dice. If one of the PCs has Audio Directionality (Professional Knowledge), I'd let them roll that + Logic to add more helping dice. If any player wants to roll Reaction instead of Perception + Intuition, I'd be cool with that but only for helping dice. Each hit in the helping dice adds 1 die to the primary roller's Perception + Intuition roll. If PCs are on the other side of this coin, I'd roll 1 die for each damage rating of the weapon. Each hit represents one security guard, lone star op, curious investigative reporter, or equally undesired attention rushing to investigate the incident or detain the player characters. |
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Jan 17 2007, 05:15 AM
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#6
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Moving Target Group: Members Posts: 732 Joined: 1-December 06 Member No.: 10,116 |
Well the fluff on the Ruger Thunderbolt says any LS officer can recognize the sound of one being fired. I dont think it says they can pinpoint the sound of it. And thats hardly unrealistic. Alot of firearms all have a sort of.. unique sound to them. So if you hear one enough, by sound alone you can tell what weapon is being fired. Pinpointing it from sound alone however at least with the human ear... just isnt posisble from one single shot. If your good/lucky you might get a general direction (Due East) But.. thats about it. If there is continued firing on the other hand you can eventualy follow the sound to it's source easily enough even by ear. Since especially with hearing augmentation you can filter out background noise etc and easily tell when your moving away from/getting closer to the sound. The main reason LS gives owners of the Thunderbolt a hard time is because it's their standard sidearm. And LS as a company actually developed it. So since it's a 'signature' weapon for all LS officers they dont like others having it. But there's really drek all they can do if you've got the proper lisence for it. But thats what happens when your corp has an R&D department but no real manufacturing base. I think it's also mostly a holdover from SR2 when it first showed up. At that point while Ruger was making them, they were NOT available for sale to the public. SR3 I think by that poitn they were -just- starting to hit the public market. That was part of the contract deal with Ruger. LS got sole 'buying rights' to the firearms for X number of years. After that Ruger got to sell it as it's own product. So orrigionally you could only get one by stealing one directly from LS. So by SR3 most officers just 'assume' you did even if tehy know you can buy one legitimately. |
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Jan 17 2007, 05:20 AM
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#7
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Moving Target Group: Members Posts: 745 Joined: 2-January 07 From: Los Angeles, CA Member No.: 10,510 |
While this may be true, it would still need a computer check. I love, love, LOVE it when people come up with awesome, creative stuff to do with AR and commlinks, but I don't see most people in the Shadowrun universe (including the runners) as necessarily knowing how to do a lot of this stuff or having the inherent instincts and foresight to prepare this stuff on the spot. I see most people today having more toys than they know what to do with and I don't see that changing anytime soon. So especially complicated, unusual, or just plain handy stuff requires a computer check. If you're a hacker or decent with computers, you can probably just buy off the hits you need for most of these checks. If the PCs have all the hardware necessary or have done this triangulation trick before during a session, I'd put the threshold for this at 2. Otherwise the threshold would be at 4. Also, they'll need a program to do this but it won't be more difficult to get than any mapsoft. 5 nuyen per rating and it can be instantly downloaded when needed. As for the "Uh... I recorded that" comments that PCs try to shrug off as common sense, yeah, that's a Computer + Logic roll. Hey, you really did record that. (But if the PCs are doing the triangulation thing, I would just assume this test is successful if the other one is, and so they only have to roll once.) |
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Jan 17 2007, 05:29 AM
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#8
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Moving Target Group: Members Posts: 116 Joined: 5-May 02 From: Sydney Sprawl Member No.: 2,687 |
Alright, so if you are prepared with a few commlinks or cyber ears then it should be quite possible, even from a single shot. Without prep then it would be possible to follow the sounds of s gun fight possibly at a reduced speed to stop and listen periodically but not really from a single shot.
Thats the sort of answer I was looking for. -Strobe |
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Jan 17 2007, 05:30 AM
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#9
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Moving Target Group: Members Posts: 548 Joined: 21-December 06 Member No.: 10,416 |
Telling where a shot came from would be very hard. As pointed out above, a single shot would be very hard to pinpoint.
In an urban environment, sound will bounce all around due to the buildings. Somtimes it can be overcome, but if the place is very built up with lots of odd angles, then it would be hard. It would be easier to locate a shooter if they were out on the street firing at you, or on a roof top. Not only would the sound be cleaner, but you could see them. If they were being very careful, like firing from a block or more away from several feet back inside the building, then it would be very hard to pinpoint them. You'd almost certainly still hear an unsilenced shot, but spotting exactly where it came from is another matter. This is why the military and police agencies are developing systems to detect gunshots and trace the bullet back to the shooter. I don't know what frequency gunshots are, but they vary. A pistol sounds different from a shotgun. A rifle sounds different from both. It takes a little practice to distinguish the difference, but with practice you can tell different calibers. Don't forget that, especially with rifles, you can hear the sonic boom of the bullet in flight, kind of a snapping sound. |
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Jan 17 2007, 05:49 AM
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#10
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Moving Target Group: Members Posts: 745 Joined: 2-January 07 From: Los Angeles, CA Member No.: 10,510 |
One commlink and audio detectors of any sort, not just cyberwear. Simple microphones or listening bugs will work. As for the list of possible factors that would make detection difficult, I think proper software would account for most of those issues (and I doubt the program would cost more than 20 nuyen). In general, there's very little a group of prepared runners can't do.
For those times that runner's insist they should have been prepared when the player's didn't specify it, I have them roll an applicable skill check or Reaction. In this case, Computer. I have one PC who likes to say he's always recording 100% of the time onto his firewall 6 commlink and he deletes what he doesn't need every night. He still has to roll or buy his hits at 4 dice each. Whether you were prepared or not, if you are using the technical triangulation method that HappyDaze recommended, then I think it can be done with a single shot. Even if the exact location can't be fixed, the user's heads up display would instantly show up five or six potential flashpoints in a small area and the user would instantly recognize which one's correct. If the players are trying to interpret recorded audio and video data after the fact to determine who the possible sniper was, then I'd rule it as Data Search. Success indicates a positive match, failure means you've limited the trajectory to a certain area or to a handful of people. Also, keep in mind that there's really no need to "stop and listen" if you can instruct your commlink to do it and then feed you the AR information. AR will allow you to keep functioning and listen simultaneously and I presume for my campaigns that people in the shadowrun universe have become expert masters at multitasking between Real Life and Augmented Reality. |
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Jan 17 2007, 05:56 AM
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#11
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Shooting Target Group: Members Posts: 1,838 Joined: 1-September 05 Member No.: 7,669 |
This doesn't fly. I don't have to tell my DVR to record anything that I'm watching - I can just hit the button 10 minutes into the show and rewind. Commlink recordings should be the same way. There is no reason that it shouldn't automatically record everything 30 minutes or more back from present. After that time, it's written over unless you choose to save it (think of it as short-term memory). If you want to, you can deactivate such a feature, but it should be recording everything as standard - that's how Big Brother would want it to work. 8) |
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Jan 17 2007, 06:00 AM
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#12
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Moving Target Group: Members Posts: 116 Joined: 5-May 02 From: Sydney Sprawl Member No.: 2,687 |
The stop and listen comment was for tracking a fire fight without electronic help. -Strobe |
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Jan 17 2007, 06:17 AM
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#13
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Mostly Harmless Group: Dumpshocked Posts: 937 Joined: 26-February 02 From: 44.662,-63.469 Member No.: 176 |
Gunshots are just a broadband impulse (multi-frequency, short duration), usually in the 140-170 decibel range within a couple meters of the muzzle (depending on the cartridge and barrel length), just to give you an idea of the nature of the sound and the level of sound pressure associated. Obviously, the environment is going to have an enormous effect on how difficult it will be to locate the origin of the shot. What's more, the muzzle blast is not the only sound that a gunshot makes. The bullet whizzing through the air at supersonic velocity makes a very loud (@155dB), tearing kind of sound sustained throughout the entirety of its flight until it drops into subsonic, then there's no more shock wave and as such, less noise (@115dB). So not only will the muzzle blast be reflected off of buildings, signs, cars, pavement and that kind of stuff within an urban environment, so will the "ballistic crack". Fortunately, the bullet noise is a very odd sound that most people wouldn't even recognize (as few films have captured it accurately; Dances With Wolves and Saving Private Ryan being two that I can think of that did a particularly good job), and the fact that the sound is very loud and originates from the bullet in flight means that people near the flight path tend to follow that sound instead of the muzzle blast, especially so if the firearm is suppressed. There are electronics available now that are designed to triangulate the muzzle blast of a gunshot. They're used in high-crime areas in some cities here in the US. Since 9/11, I would expect these kinds of systems to have been installed in the downtown areas of many of the bigger cities. Obviously, they have to be set up where a gunshot is expected to occur. They can also be fooled by reflected sounds.
That has more to do with automatic weapons than the sound of a single gunshot, mostly the frequency of the rate of fire. It's easy to tell an AK from an M4 because the AK fires at about 600 rpm, whereas the M4 fires as about 800-900 rpm. Otherwise, the shots tend to sound pretty much identical as the powder charges, pressures, and barrel lengths are very similar. This would also be the case with the Thunderbolt, being an automatic pistol with an unusually fast rate of fire. To a trained ear, it can certainly be possible to tell the difference from an average handgun to an average rifle with a single gunshot, but a lot of factors have to be taken into account in order to make that assessment in any way accurate. For example, .44 magnum revolver can sound an awful lot like a rifle shot if you're unaware of the distance to the shooter or you're unfamiliar with the environment the shot occurred in. It's generally very easy to tell the difference between a modern firearm and a black powder firearm, but I doubt that's going to happen in SR much. Shotguns also tend to sound fairly unique, as they fire at relatively low pressures compared to other modern firearms.
On the contrary, it can be very easy. It once again depends quite a lot on the environment. I've been more than a mile away from a fellow hunter and tracked her down from a single gunshot. Of course, she hadn't moved but a couple of hundred yards from the time the shot was fired until I made my way over to where she was, but it was relatively broad, open environment we were hunting in, with relatively few trees and hills to absorb or reflect the sound waves (pronghorn hunting in eastern Montana). The more things there are between and around the source and the pick-up, the more difficult it tends to get to find the origin. Overall I think making up rules for this kind of thing would be a bit ridiculous. The GM should just set a target number based on what he thinks the difficulty should be and apply a perception check (or whatever the equivalent is in SR4). |
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Jan 17 2007, 06:19 AM
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#14
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Moving Target Group: Members Posts: 732 Joined: 1-December 06 Member No.: 10,116 |
Possible from a single shot IF your setup to triangulate. And its stil a very big 'if'. Since the If depends on a good many circumstances. If I was going to make it a threshold in an urban invironment and the team was setup with the proper equipment in advance. I'd say maybe threshold 2 if it was close, to threshold 4 if it was much farther away. Due to echo etc. With the normal ear? Froget it unless the guy is relatively close when he fires. Again relative is abit of a big term. In an urban enviroment close means pretty close. On say.. a lake on a calm day? Well damn.. you can hear a gunshot clear across the lake on a good day no problem. Though at that point all you really know (unless you happen to see the person with a gun) is that by golly. some one across the lake somewhere fired a gun. |
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Jan 17 2007, 06:25 AM
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#15
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Running Target Group: Members Posts: 1,011 Joined: 15-February 05 From: Montréal, QC, Canada Member No.: 7,087 |
Err, it's trivially easy to know the direction IME. What, no one has ever been in presence of a loud snapping kind of noise? And how long did it take you to face the direction that noise came from? A fraction of a second, right? When I was doing military exercise, I always instantly knew the direction the shot were fired from (blanks of course!). The exact location of the shooter is quite something else, but figuring the general direction is about as hard to process as maintaining balance while walking. It's natural for the brain. In fact, I bet most people will look in that direction reflexively before they have fully registered what is happening. A soldier would dive for cover first instead of standing looking. Of course he wouldn't be able to get adequate cover if he didn't immediately realize the general direction of the shots. Unless you are running undergound with echoes everywhere or the gun shot is drowned in even louder noise, it's not much of a challenge. Years of evolution taught us to locate approximately the direction of scary noises so we can run the other way. Once you look in the correct direction, spotting the exact location of the shooter depends on the circumstances. It can be impossible to miss to almost impossible to spot unless he fires again (which a sniper probably won't do). --- Bottom line, in most circumstances, I'm not even asking for a perception test : I'm just telling the PCs they heard gunshot in that direction. From that point, locating the shooter will or won't be a challenge depending on the situation. |
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Jan 17 2007, 06:41 AM
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#16
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Moving Target Group: Members Posts: 732 Joined: 1-December 06 Member No.: 10,116 |
Yeah but what if the gunshot was say.. from behind a building, 3 buildings over 'that away'? What if the buildings are skyscrapers? While I dont disagree that you'd still have a general idea of where the gunshot is from in many situations. I cant help but wonder how accurate that perception will be in some cases. I've certainly heard gunshots (from hunters) while sailing and such on lakes. Some times especialy when your out on the water, even though it's a totally flat surface it's pretty much impossible to tell where the ehll the shot even came from because it echos all over the damn place. There are other times I definately knew it was say.. off to the general right... somewhere in a 100 degree angle or something. But thats a crazily broad area to define.
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Jan 17 2007, 07:11 AM
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#17
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Moving Target Group: Members Posts: 745 Joined: 2-January 07 From: Los Angeles, CA Member No.: 10,510 |
So sometimes you succeed at your perception tests and sometimes you fail? What a foreign concept... :) |
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Jan 17 2007, 07:18 AM
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#18
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Running Target Group: Members Posts: 1,011 Joined: 15-February 05 From: Montréal, QC, Canada Member No.: 7,087 |
Accurate enough in most situations where you are the target. If he fired at someone else "three building that way", you can start running in that direction if for some reason you like running toward an armed man. You should be able to pick up cues from the movement of the crowd if there is one. As you get closer you'll refine your perception if he's still shooting. The perception test tells you how good you are doing. If he's not firing anymore by the time you arrive, get the forensic team, it's time to play CSI with the various recording and find that shooter on the grassy knoll! I'm not saying you can automatically locate the shooter. You just pretty much always know the direction under normal circumstances. And it's actually a pretty accurate direction too if it's reasonably near. |
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Jan 17 2007, 07:25 AM
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#19
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Moving Target Group: Members Posts: 745 Joined: 2-January 07 From: Los Angeles, CA Member No.: 10,510 |
Yes, your DVR example proves that the technology exists and its possible. Sure. I'm talking about the human element. Hence, the computer check. Most people don't even know what all the programs do in their computer. Even people who are more-or-less computer saavy don't know how to use search engine parameters beyond simple keywords. Or if they know how, they don't use them, even when they need them. And then they go on forums or chat with me to find an answer that took me three seconds to find in google. Some people can't even name more than 5 search engines off the top of their head. I'm assuming this human element of the technical equation never changes. Besides, I don't want to get into any arguments about it with my players in the middle of a game. If you want to use all kind of cool technical whazoos, take the computer skill. Then, in game, when a situation comes up when its necessary, you can roll Computer. Simple. No argument. It speeds up play, it makes sense, it gives technical proficiency to technically oriented character, players get to roll dice, it's cool. It's just like I'm not going to let PCs say "I'm walking carefully to avoid any tripwires or pressure plates" without actually making them roll for it. Maybe they'll get a bonus or something, but they still have to roll no matter how good their narration is. Same deal with the AR and commlinks. Of course, it works on the other side of the credstick as well: Sometimes the players don't know exactly what they would do, but we're pretty sure AR would help. They can roll their Computers for that, too. Their hits make a sort of AR bonus and we try to explain it as best we can. One example of that when a player with a terrible commlink, no hacking, and very little computer skills told his motorcycle to plot a course in case he needed to make a quick and stealthy escape. I thought that was cute and we narrated right by it but then later that scene, when he left, he got chased by a roto-drone and so then we rolled for the course plotting done earlier. We rolled the motorcycle's Pilot dice as helping dice for an opposed Driving test to get away. I only allowed it in the first two rounds, but he got a couple of extra hits from it. I'm very big on helping dice. I think they're the coolest part of the game. |
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Jan 17 2007, 07:35 AM
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#20
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Moving Target Group: Members Posts: 732 Joined: 1-December 06 Member No.: 10,116 |
Ehh.. it's not really a case of pass/fail on a perception test. It's the sort of time I'd ask when one is even needed. And if one passes. Just how much it could plausibly tell you. Afterall techncially speaking if you go by pure RAW a single perception test coudl tell you the precise location of a shooter from a single shot 1000 yards away across a body of water. Even with 'augmented hearing' this isnt, I feel even remotely realistic. |
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Jan 17 2007, 01:05 PM
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#21
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Running Target Group: Members Posts: 1,150 Joined: 19-December 05 From: Rhein-Ruhr Megaplex Member No.: 8,081 |
I hear automatic weapons fire every other day, because there is a military shooting range somewhere near. But, I can't pinpoint the exact direction or range (lots of buildings and trees that way). In fact, depending on the room I'm in (or where I'm standing outside) the sounds seem to come from different directions...
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Jan 17 2007, 01:15 PM
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#22
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Moving Target Group: Members Posts: 745 Joined: 2-January 07 From: Los Angeles, CA Member No.: 10,510 |
Maybe it is. Maybe you're surrounded. Maybe they really are out to get you... |
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Jan 17 2007, 02:45 PM
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#23
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Target Group: Members Posts: 8 Joined: 30-December 06 Member No.: 10,496 |
Would a Spatial Recognizer work to find the direction?
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Jan 17 2007, 03:00 PM
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#24
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Moving Target Group: Members Posts: 944 Joined: 19-February 03 Member No.: 4,128 |
That is exactly what it is there for. It gives you a bonus to your Per Roll for exactly that purpose.
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Jan 17 2007, 03:12 PM
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#25
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Target Group: Members Posts: 8 Joined: 30-December 06 Member No.: 10,496 |
I figured that, but some here are saying that a human can't find the source at all (with only 1 shot fired). What I'm asking is there a chance with SpatialR. or is it still a waste of time trying to find the shooter? Would some of you GMs allow a test roll or would you just state that the runners can't locate the shooter from only 1 shot fired? |
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