Shulou(Shulou.com)11/24 Report--

In our daily life, we always want to find a quiet place, especially for the friends living in the city, to buy a house far from the road, to choose multi-storey sound insulation for home or office decoration, and cars to choose sound insulation, and so on.

Always feel that no matter where it is particularly noisy, rarely have a quiet moment, these annoying noise will always make people upset, so people are constantly thinking of ways to eliminate the noise.

Photo Source: pixabay when we think there is noise everywhere and are constantly looking for ways to isolate it, imagine what it would be like to put you in a world where there is no noise at all.

Someone has created what can be called a "completely quiet" room, called Orfield Lab, which is made of special sound insulation and sound-absorbing materials on all sides.

It is said that this room can absorb 99.99% of the sound. What will it feel like? you can't hear the sound outside at all, so that you can only hear the sound of the human body, the sound of breathing, and the sound of heartbeat.

If you stay in here for a while, you will miss the noisy world outside, because it is so depressing that many people will experience it, but no one can last more than an hour.

It is often seen in some professional recording studios or some entertainment rooms, there will be some sponges with waves or peaks, these sponges are affixed to the wall for noise reduction.

In our impression, what is needed to block sound is an object that is sealed, strong and thick enough to block the transmission of sound. How does a soft, porous object like a sponge absorb sound?

What is sound-absorbing cotton? sound-absorbing cotton is a kind of sound-absorbing and noise-reducing material composed of fibers. these fibers are intertwined with each other and are filled with a variety of small and irregular pores.

There are many kinds of sound-absorbing cotton, so there are many nicknames, such as egg cotton, soundproof cotton, wave cotton, wave cotton, sound-absorbing material and sound insulation material and so on.

Sound-absorbing cotton can not only absorb and insulate sound, but also has the properties of heat insulation, moisture-proof, anti-impact and anti-corrosion, and it also has a certain decorative effect by making various shapes of sound insulation cotton.

This kind of sound-absorbing material with many advantages is widely used in interior decoration of recording studio, KTV, studio, conference room, studio and theater.

How noise is produced if you want to know how sound-absorbing cotton blocks noise, you must first understand how noise is produced. In fact, sound is a wave generated by the vibration of an object, and then transmitted through a medium such as solid, gas or liquid. A wave phenomenon that is received by a person's ear.

In life, when we knock on the door, speak, or sound sirens, their vibrations will cause air molecules to vibrate according to a certain rhythm in the air, causing the surrounding air to fluctuate and form waves that spread outward. This is the process of producing sound waves.

This sound wave continues outward until the vibration gradually weakens and disappears, which is like throwing a stone into the water. The middle wave is the clearest, and the outer circle wave gets bigger but more blurred until finally the wave disappears completely.

How to eliminate noise people have been looking for ways to reduce noise, especially in some special industries, the less noise, the better. There are usually three ways to reduce noise.

One way is to control the noise at the source of the sound, that is to say, to reduce or stop the vibration of the sound body, this method is to make the noise disappear directly from the sound source, and when the sound source is directly allowed to stop vibrating, there is no way to continuously produce vibration in the air.

The second is to block out the noise in the ear where the sound is received, for example, wearing earplugs can effectively reduce the volume of noise entering the human ear, even if it does not change the sound source and transmission route.

The third is to let the sound in the process of transmission through blocking, filtering and absorption and other methods to gradually reduce or even stop the spread of noise, such as the sound-absorbing cotton used in decoration, so how on earth do these sound-absorbing cotton with a lot of pores and looseness achieve noise suppression?

Photo Source: the principle of pixabay sound absorbing materials generally show a large number of pore structures inside sound absorbing materials. When sound waves propagate, they will be decomposed into these pores respectively, and the sound waves entering the pores will be constantly reflected. In this process, the sound waves will be gradually consumed and weakened, so the sound through the sound absorbing materials will be greatly reduced in the end.

It is also common to see the use of tapered or egg-shaped wave peaks or wave sound-absorbing sponges. By the same principle, when sound waves pass through sound-absorbing materials with shapes, layers of sound waves will first be decomposed, and the decomposed sound waves will enter the pores of sound-absorbing cotton and be consumed and weakened again to achieve the effect of sound absorption.

Because sound travels at different speeds in different media, and it travels faster in solids than in gases, we begin to use these principles to combine solids with gases to achieve sound insulation and noise reduction, such as the commonly used multilayer hollow glass.

When the sound wave first passes through the solid glass, it will be blocked, and when it enters the hollow layer of the gas, the sound wave will attenuate again, and the sound wave will pass through the solid glass again. It can be seen that if the sound is to pass through multiple layers of hollow glass, it needs to be propagated in different media.

In this process, the sound waves will continue to be blocked, it will become weaker and weaker, and finally the noise through the glass will be much less.

In fact, not all sounds are harmful, we often need to tell the direction by sound, and there are some sounds that can improve the quality of sleep, so that now there are some App to collect all kinds of noise to treat some people's insomnia.

The picture in this article is taken from Youtube "Vocal Isolation Recording Booth Build Time Lapse-QC Acoustics"Can Silence Actually Drive You Crazy".

The gif is intercepted from Youtube "Sound_ Crash Course Physics"Principles of Acoustics".

This article is from the official account of Wechat: manufacturing principle (ID:zhizaoyuanli), author: Lao Zheng

Welcome to subscribe "Shulou Technology Information " to get latest news, interesting things and hot topics in the IT industry, and controls the hottest and latest Internet news, technology news and IT industry trends.