Sound Diffraction Explained: What Is It & How Does It Work?

In summary: This is why some soundproofing material is very heavy and stiff.In summary, sound diffraction occurs when sound waves bend around small obstacles and spread out beyond small openings. This is why we can still hear someone's voice even when they are in a closed office. The sound is attenuated as it passes through the material of the door, but the ear's sensitivity to weak sounds allows us to still hear it. Sound can travel through the thickness of doors because it is a mechanical vibration that can be transferred from one medium to another, such as from air to the material of the door to air inside the office. The energy of the sound is transferred through the door and into the air inside, allowing us to hear the sound even when the
  • #1
einstein1921
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0
Hi, my friends. Today, I come up with a question suddenly. It is about Sound diffraction.
why can we hear someone's voice even when he is in a closed office. Many books says that it is because of Sound diffraction. But I can't understand. how does it happen? would you be so kind to explain it in detail? Thank you!
 
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  • #3
But the office is closed!

Don't forget that sound can travel through the thickness of doors, and even through some sorts of wall. The sound is attenuated (weakened) but here something else comes into play...

The ear's sensitivity is 'logarithmic'. This implies that it is disproportionately sensitive to very weak sounds. So although the sound intensity might fall by a factor of 1000 as the sound passes through the material of the door, it may still be audible.
 
  • #4
Philip Wood said:
But the office is closed!

Don't forget that sound can travel through the thickness of doors, and even through some sorts of wall. The sound is attenuated (weakened) but here something else comes into play...

The ear's sensitivity is 'logarithmic'. This implies that it is disproportionately sensitive to very weak sounds. So although the sound intensity might fall by a factor of 1000 as the sound passes through the material of the door, it may still be audible.

why sound can travel through the thickness of doors? please explain it ! Thank you very much!
 
  • #5
or you confused sound with light,which can not go after a wall.Sound can,right!
 
  • #6
einstein1921 said:
why sound can travel through the thickness of doors? please explain it ! Thank you very much!

Sound is a mechanical vibration in a medium. It can be transferred to another medium. So ... inside air to wall to outside air. It gets attenuated each time, which is why you don't hear the sound as clearly outside the office as you do inside the office.

EDIT: it can also be reflected off of objects (mostly hard, smooth ones), thus can "go around corners"
 
  • #7
Sound travels through solids and liquids as well as gases such as air. In a liquid or solid, the vibrations which make up the sound are passed from one particle to another via the forces which hold the particles together. In many materials (such as steel) the wave energy propagates very efficiently in this way. In softer materials, or materials containing large particles or fibres, much of the energy is scattered or dissipated (making the material slightly hotter), so the sound propagation is inefficient. That's just what you want in the material of a wall or door.
 
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  • #8
As an extension to what phinds said...
The sound is the vibration of the air. The vibrating air is in contact with the wall, and transfers some of that energy to the wall. Now the wall is vibrating. The vibrating wall transfers some energy to the air inside the office. Now the air inside the office is vibrating, allowing you to hear the noise, even if the office is sealed. If the door is very thin, you hear more through it, because it's easier for the air to vibrate the door. If you make the door very heavy and stiff, it's harder to get the door to vibrate, so less energy is transferred through it. If you make the door infinitely stiff and heavy, then no sound energy passes through it.
 

What is sound diffraction?

Sound diffraction is the bending and spreading out of sound waves as they pass through an opening or around an obstacle. This phenomenon occurs because sound waves have a tendency to travel in a straight line, but when they encounter an opening or obstacle, they can spread out and bend around it.

How does sound diffraction work?

Sound diffraction is caused by the interference of sound waves. When a sound wave encounters an opening or obstacle, it splits into multiple waves and these waves interfere with each other as they pass through the opening or around the obstacle. This interference causes the sound waves to spread out and bend, creating the diffraction effect.

What factors affect sound diffraction?

The factors that affect sound diffraction include the size of the opening or obstacle, the distance between the sound source and the opening/obstacle, and the frequency of the sound wave. Generally, smaller openings or obstacles and shorter distances will result in more significant diffraction, while higher frequency sound waves are less likely to diffract.

Why is sound diffraction important?

Sound diffraction is important because it allows sound waves to travel around objects and through openings, making it possible for us to hear sound even if the source is not directly in our line of sight. It also affects the quality of sound in different environments, as the diffraction of sound can cause echoes, reverberation, and other acoustic effects.

How is sound diffraction used in real life?

Sound diffraction is used in many real-life applications, such as in the design of concert halls and other performance venues to improve acoustics. It is also utilized in the design of speakers and other audio equipment to create a more immersive listening experience. In addition, sound diffraction is studied and utilized in fields such as sonar and ultrasound technology to detect and analyze sound waves in various environments.

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