The Sound of Silence

car-1882691_1920

This post was written by our overseas contributor, Paul. He’s from the U.K. so I’ve provided some interpretations for those of us in the U.S. Just having a go at you, Paul.

  • Indicators = Turn Signal
  • Windscreen = Windshield

The Sound of Silence

When you use a car all day every day you begin to recognize its individual sounds. The sound of the ignition starting up, the sound of the windscreen wipers, the sound of the indicators. When you hear a noise you don’t recognize you instantly get the feeling something is wrong. But stepping back a bit, why do cars make any noise at all?

We assume cars make a noise for the same reason jet airplanes make a noise–big engines are noisy. It’s all do with their mechanical nature. Despite the fact that many components in a car have become computerized, it is still really a mechanical object.

Internal combustion engines suck a fuel-air mixture into two or more chambers, and POW, there’s a series of explosion. Tiny explosions, sure, but it’s going to make a noise. That sound would actually be quite a bit louder except for the exhaust system which channels the exhaust and sound back along the bottom of your vehicle to dissipate it before dispersing it out to the world. Along the way, it goes through a muffler designed specifically to reduce the sound. (Except, of course, for the jerks that live behind my house, who’ve never heard of a muffler.)

But some noises are harder to place than others, the sound of rubber tires on the road is something we all recognize, but why do objects like the windscreen wipers and the indicators make the noise that they do?

Although they are performing mechanical functions, the circuitry performing these actions helps create a noise. In the case of the indicators, what we hear as a click is a circuit whose function is to cause the indicators to flash. This might not make much sense, as we encounter lights all day long which don’t make a noise, apart from some humming, but because the indicator is needed to flash, there needs to be a certain type of circuit here.

Why does a faster car make more noise? Well, when a car is accelerating its exhaust has to work harder. It’s quite complicated what is going on, but in layman’s terms, it is a mixture of axles, pistons, and transmissions which need to work harder in order to increase the speed. More work means more energy, which we hear as sound. This is also why the engine is more vocal when you start the car up, especially on cold days.

We tend to be more suspicious of the less mechanical noises, the thumps and the twangs, such as may happen when the tires rub against metal or something in the trunk hits the side of the car. It might be part of our survival instinct; no one wants to drive a vehicle which is a death trap. If there’s a problem it should be fixed. It doesn’t mean that everybody takes notices of these sounds, but many drivers feel it is part of maintaining a car properly.

One fun fact, new cars often come with long mileage tires which have very hard rubber. So they will make a lot more sound inside your car than the ones you put on later.

So what about a silent engine? Well, that can only be achieved by an electric car but they provide their own problems. Pedestrians are used to cars making a noise, so when they don’t hear a car they feel that no car is there. It makes sense, therefore, to add sound to the noise of the electric car. The only problem is that a selling point of an electric car was its smooth movement, its lack of noise. So you remove this if you add a different noise when the car is in motion.

For good or bad it seems that cars will be noisy for quite a time yet.

Leave a Reply