Home > Uncategorized > Silencers are like car mufflers, but for guns.

Silencers are like car mufflers, but for guns.

Being a classic renaissance man, I have no idea how a car actually works. There’s a big gap in my understanding of what (as they say) is going on under the hood. From my viewpoint, this is how things happen in a car.

1. Turn key in the ignition.

2. Magic

3. Car moves.

As a result of this misunderstanding (though it’s not really a misunderstanding since there’s no mis about it, it’s total not-understanding) I, by association, didn’t understand how a muffler works. I knew what they did because of personal experience. The muffler fell off one of my first cars while I was at a friends house. I spent the whole car ride home imagining that I was a Nascar driver Even at the highest possible setting, I couldn’t hear the radio over the exhaust. Also, since the break occurred in the middle of the car body, I probably suffered just a bit of brain damage from sucking fumes. I never could begin to imagine just how mufflers could make engines quieter since mufflers look like a giant metal fig newton. I had always assumed that they were empty, or maybe filled with some sort of delicious jelly.

Again, my reasoning for thinking that mufflers were hollow and yet still able to quiet engine noise was because I was sure that magic was involved somehow. It turns out that i had completely oversimplified what a muffler is. Its design is actually fairly complex. First there’s the inlet pipe, which leads from the engine to the muffler. This pipe is perforated within the muffler so that gases and exhaust can escape through the perforations, reducing the pressure in the main pipe. Since sound is a pressure wave, this reduces the noise level, but not usually enough to make the car noise pleasant to be around. To aid that further, the muffler is made of sound absorbing material.

To aid that further further most mufflers are divided into three sections. The bulk of the exhaust from the inlet pipe is released into the section furthest from the engine. From their, it bounces off the back wall, through a hole into the second section. From their, the sound waves hit the inner wall of the first section. The first section of the muffler is closed off from the rest of the muffler and is called the resonance chamber. The resonance chamber is precisely measured to make an interference frequency of the sound wave created by the exhaust. In essence, the muffler acts like those fancy shmancy noise cancellation headphones. The sound waves that the car makes are cancelled out by the interference waves created in the resonance chamber.

That’s so cool. In fact, you can get specialty made mufflers for precision engines to give your car a specific sound.

After getting bounced around, the sound waves and exhaust pass into the outlet pipe, which is also perforated, and then leaves the muffler.

So there’s three steps in how mufflers work, and none of them involve magic. There’s the interference frequency, the insulation, and slowing down the rapid expansion of gas. The third method is used by silencers to deaden the noise made from gunfire. When a bullet is fired, it’s actually pushed out of the gun barrel by the rapid expansion of high pressure gases created when gunpowder ignites. What a silencer does is increases the volume that the gas has to travel through before exiting the gun. Silencers are filled with a bunch of empty chambers that gas can vent into and out of, without affecting the bullet’s travel. This has the same effect as letting he air out of a balloon before popping it.

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