Wapsi Square Forum

Alkarii wrote:I found out this morning that virtually every depiction of suppressors that I'd seen is wildly inaccurate. An ambulance siren is typically about 120dB, and OSHA requires hearing protection in work environments where the noise level reaches 140dB or louder.

Suppressed rifles can typically reach 130dB or so.

Well, you know... That's Hollywood for you... It wouldn't make as "good" a story, if they stuck to the truth...



Incidentally, I was measured once, to find out the volume of my voice, as I had just played a town crier in a Christmas play (without microphone... they heard me well enough in the back of the church...)

Apparently, I can reach 107dB... And when I asked them what they usually set the speakers to, they replied 102dB...
(Naturally, with two speakers, and the fuller sound of all singers and band player on a regular Sunday morning, that makes for a louder experience, but I could still make myself heard over it - or at least, in the midst of it, if I really wanted to...)

140dB? Er, try again -- it's 85dBA over an eight hour period. That is, an average of 85dB using the "A"scale - dBA.



Keep in mind the Decibel scale (named for Alexander Graham Bell and his work on sound and deafness) is Logarithmic, not linear. Every 10 dB is a power of 10. Going from 20 to 30dB is from 100 to 1000, and so on. The problem is the Power of the sound vs how the ear and brain perceive the sound.



Technically, if you double the physical pressure of a sound wave, that's a 3dB increase in power (the energy to move things). If you measure the wave power electrically, it's 6dB. But by perception, doubling the human ear "loudness" is a 10dB increase.

So the Suppressor is very much NOT a silencer. Dropping that Jet Engine screech to a mere Jackhammer rattle is a 10dB improvement, but sure as hell not "silenced." People learned this from movies, the same way they learned that setting off one fire sprinkler will somehow flood the entire building. Er, no.

As someone who works in an environment where you have to be within elbow distance to talk (loudly) and be understood, let me say metal saws are very, very loud. The 30dB Noise Reduction Rating earplugs do a fine job of dropping that shriek to tolerable levels.

Info from OSHA and here.

Alkarii wrote:I found out this morning that virtually every depiction of suppressors that I'd seen is wildly inaccurate. An ambulance siren is typically about 120dB, and OSHA requires hearing protection in work environments where the noise level reaches 140dB or louder.

Suppressed rifles can typically reach 130dB or so.

The rules are even stricter than that. The employer must make free hearing protection devices available to employees whose time-weighted average noise exposure is above 85 dB for an 8-hour day. The way OSHA rate it, that corresponds to 90 dB for 4 hours, 95 dB for 2, 100 dB for no more than an hour, 105 for no more than 30 minutes, etc.

140 dB is the "threshold of pain" - even with 30 dB of noise attenuation (typical of good foam earplugs) OSHA rules would say you shouldn't be exposed to this for more than about 15 minutes a day!

IMO, anyone who uses firearms without using hearing protection is seriously risking their hearing in the long run. When hunting I can see that this would not be practical for safety reasons, but please always use good hearing protection when you're practicing on the firing range!

Ah, okay. What I had read was that OSHA required hearing protection to be worn at all times in an environment that loud, and I felt sure that it'd still be a good idea to wear them at the 120. Speaking of which, I think I'll grab some earplugs at the end of my break. I don't think it gets too loud at my work station, but still, even prolonged exposure to some loud noses at the somewhat lower volumes than those that require protection can cause other effects.

As for metal saws, I know all about those. There was a guy who had to use those at my first job, and it could interfere with a conversation quite a distance away from him.

Re: Suppressors: Ever since Tom Clancy kinda broke the magic around 'Silencers', I've been under the understanding that the best you can hope fore in an off-the-shelf suppressor is to muffle the sound and more importantly; reduce the locationablity of the round being fired. In other words it help to reduce folks from pinpointing your location.

Now, that said, there are 'whole package engineering' firearms that actually & greatly reduce the noise- but at a cost. The velocity goes way down, hence the 'throw' or distance the round can travel, as well as the long term accuracy.

And then there are railguns...

For what it's worth, I play an online shooter called Fortnite. You and 99 others (teams or solo) land on a large-ish island and battle it out with whatever weapons and materials you can find and build. The weapons fire sounds are very realistic -- each has their own sound firing, compensated for distance (and echoes!), as well as a distinct whizz as it rushes past your sorry self running as fast as you can...

OK, the Suppressed weapons are a bit on the Hollywood Poofy side, but the snap of the bullets aren't. Fun stuff if you like that sort of thing. Headphones very valuable to hear the enemy moving nearby.

One thing I liked when at the live fire ranges in Ft. Benning was that, if you were far enough away from the shooter, you could hear the bullet flying at supersonic speeds after the initial report of the rifle.

Alkarii wrote:One thing I liked when at the live fire ranges in Ft. Benning was that, if you were far enough away from the shooter, you could hear the bullet flying at supersonic speeds after the initial report of the rifle.

If you're standing in the right position relative to the shooter you can see a .45 round going downrange...

Alkarii wrote:I found out this morning that virtually every depiction of suppressors that I'd seen is wildly inaccurate. An ambulance siren is typically about 120dB, and OSHA requires hearing protection in work environments where the noise level reaches 140dB or louder.

Suppressed rifles can typically reach 130dB or so.

There are a few that are actually quiet enough that the loudest noise is the action of the gun cycling, but those are ones where the entire gun is purpose-built that way with its own specific suppressor. Ones that are just screwed onto the end of a regular gun make it quieter (relatively speaking) and harder to pinpoint where the noise came from, but you're still definitely going to have everybody in the area know that something just happened.

The most common military uses of suppressors are to make snipers more difficult to locate (people can tell that shots are being fired, but it's hard to tell from which direction they're coming), or for something like making a tactical entry into a building (lots of automatic weapons firing at once within a small enclosed space can be a tad discombobulating to everybody concerned, although sometimes you might want to actually use that disorientation to your advantage).

AnotherFairportfan wrote:If you're standing in the right position relative to the shooter you can see a .45 round going downrange...

You can even see as small as 5.56mm when they're heading roughly in your direction, especially if it's something like a machine gun firing lots of bullets. It's like a bunch of little pencil marks drawn on the landscape. I wouldn't recommend going out and trying to see them that way on purpose, though.

I thought another purpose of screw-on or makeshift suppressors (I’ve heard of oil filters, 2-liters filled with fluff, and a potato jammed into the muzzle)is to make the gunshot not immediately recognizable as a gunshot. Aka, people who aren’t trained to recognize suppressed gunshots will not be sure what it is - “was it a gunshot, someone dropping something large and hard, the house creaking, a car backfiring, or the cat? Eh. Probably just the cat.”

GlytchMeister wrote:“was it a gunshot, someone dropping something large and hard, the house creaking, a car backfiring, or the cat? Eh. Probably just the cat.”

If your cat suffers from that sort of flatulence, I'd say you ought to be buying a different brand of cat food... or, at least, increase the poor beast's Beano supplementation levels a lot.

Alkarii wrote:I found out this morning that virtually every depiction of suppressors that I'd seen is wildly inaccurate. An ambulance siren is typically about 120dB, and OSHA requires hearing protection in work environments where the noise level reaches 140dB or louder.

Suppressed rifles can typically reach 130dB or so.

https://warisboring.com/heckler-kochs-s ... s-a-shout/

70 DB for the H&K MP5 - it all depends on the gun, the round, etc, etc. So it depends

The _main_ purpose of a suppressor is to muffle the detonation noise (shockwave) that happens immediately after the bullet exits the barrel of the weapon. A supersonic round still has the very loud CRACK!, and a subsonic round will have a sizzle. Ported barrels are similar, in that they vent the gases over a longer period - with the downside of losing muzzle velocity and increasing visibility.

If you want to understand some of the difference between them, take two guns to the range. 1) a revolver. 2) a semiautomatic. Use similar calibers if at all possible, like 38 special and 9mm NATO. (often called 9mm Luger). (There are 3 9mm rounds. 9x17, 9x18, and 9x19. In order, that's .380 auto, Makarov, and Luger, now NATO)

If you can, get an 1895 Nagant as well.

With the revolver, you lose gases at the gap between the cylinder and the rear of the barrel. This tends to give _two_ separate detonation sounds if you listen closely. Thus the 'ba-boom' in comics and such). The first is when the bullet enters the barrel, and the still burning propellant explodes out the sides of the front of the cylinder. The second is when the bullet leaves the barrel.

With the semi-automatic, you _also_ lose containment twice, but in a different way. The detonation pushes the bullet into the barrel, but it ALSO shoves the slide backwards (Newton wins again) When the slide reaches a certain point, it opens a hole into the firing chamber, and the empty shell is thrown out. In a gun like the CZ-52, this can cause enough rotational force that you have to deliberately compensate for it, or watch your hand twist, and the barrel go .. interesting directions. The other is, of course, when the bullet leaves the barrel. I don't remember in which order they occur (bullet escape and ejection).

The interesting puppy is the 1895 Nagant. The Nagant brothers put together a bunch of different people's ideas, and came up with a -gas sealing revolver-.

http://www.guns.com/review/what-we-want ... revolvers/

If you fire it, the _only_ explosion will come from the end of the barrel. From the cartridge to the end of the barrel is an unbroken tube once you've pulled the trigger, until you then release the trigger. This reduces the noise to a single event. As the round is already sub-sonic, adding a suppressor gives you the closet thing to a true assassins weapon that you'll see outside of the specially redesigned semi-automatic .22 shorts. (Slide doesn't go back, subsonic round. One shot, but deadly close up)

Fun gun to shoot, PITA to reload, and even more of one to clean.

So - even with a silencer, most revolvers are noisy as snot. Semi-automatics are quieter, but still create noise with the slide action. If you want to stun a burglar, fire a shot from a revolver - the shock wave alone will knock them back a step, especially if they're used to pop-guns and the movies.

Due to Hollywood, what most people know of gunfire audio is the equivalent of the Wilhelm scream. I'm sure somebody out there has a library of pops, blams, kabooms, and pows they hire off to movie directors. Consider, too, that some sounds simply don't reproduce well in movie audio. For example, anybody who's ever been near an 1960-70s Volkswagen Beetle will surely remember the high pitched ring from exhaust when accelerating. I've never heard movie audio replicating that.

Atomic wrote:Due to Hollywood, what most people know of gunfire audio is the equivalent of the Wilhelm scream. I'm sure somebody out there has a library of pops, blams, kabooms, and pows they hire off to movie directors.

The same is true of the sound of thunder. Most of us Boomers grew up, thinking that thunder sounded amazingly like a stagehand hitting a large sheet of metal with a hammer.

The problem is known in the trade as "the folly of the fully Foley."

(Dave offers a complete set of the "Environments" natural-sounds LP albums to the Alliteration Amphora)

Atomic wrote:Due to Hollywood, what most people know of gunfire audio is the equivalent of the Wilhelm scream. I'm sure somebody out there has a library of pops, blams, kabooms, and pows they hire off to movie directors. Consider, too, that some sounds simply don't reproduce well in movie audio. For example, anybody who's ever been near an 1960-70s Volkswagen Beetle will surely remember the high pitched ring from exhaust when accelerating. I've never heard movie audio replicating that.

Yes. There are a number of libraries of sound effects. "Falling from Heights" (1,2, and 3), "The Gas Chamber", and a number of other 'death' sounds is one album. The reason the "Wilhelm Scream" has stuck around as long as it has is that it is a known sound, and works well.

Windows shattering is another sound that's hard to replicate. When I was working a production, we had to do it with a box of pieces of steel. If you tilted it right, it sounded VERY close to glass breaking.

There e actually that are referred to as a "Wilhelm Scream" - they were all recorded in a single session for the 1951 film "Distant Drums", probably by Sheb Woolley..

They were used in films and TV rather sparsely until Ben Burtt was rummaging through sound effect libraries at multiple studios and used them in Star Wars {and don't give me that "Episode IV/A New Hope" stuff - i read the opening credits at a preview showing two weeks before the official release date} - and apparently in all the rest of the "Star Wars" and Indiana Jones films, as well.

After that they became a sort of industry in-joke.

========================

Some of the sound effects Burtt created for the "Star Wars" series were wonderful - the TIE Fighter sound effect is based on a bull rhino's bellow {also used for the horn sound of the truck at the end of Duel...}, and the blaster effect is primarily based on a sound he recorded by putting a contact mike on a guy wire of a ridiculously tall radio mast - i think KVLY in North Dakota, which is over 2000 feet high, which is the tallest structure in the Western Hemisphere and fourth-tallest in the world - and whacking it with a mallet.

https://xkcd.com/1969/

Snowstorm update -- 10 inches so far in my driveway in South Central Pennsylvania. Work closed for day, and more time to ... ah... do ... something....

Well! Time to do something! Better sort my Somethings list. I'm sure there's a do-able item on it somewhere. I've been waiting for someday to do it, and it looks like this is the day. Yep -- stop procrastinating, put off the delays, concentrate my focus, and make a determined effort to... ummm... where are my glasses?

BRB.

I'm getting really tired of having to beg my bank for permission to use my card to buy something to eat when I still have more than $400 in my account.

You might want to see if you qualify to join any of the local credit unions. They generally offer the same sorts of services as banks (savings, draft accounts with check-writing and online bill-pay, and credit cards). Pretty much by definition they are not-for-profit cooperatives, so their rates and costs may be better than you'll get from a commercial bank, and they usually have a good focus on providing quality service to their members. Most of them are members of a shared-ATM network, which means you can get cash (and in many cases do deposits) at other credit unions' ATMs without paying a fee.