Reflection, Diffusion, Absorption of Sound

Reflection, Absorption, Diffusion, and Transmission of Sound

​Diffusion -
When a sound wave hits an irregular surface like foam or carpet, the vibration breaks up and travels along many much smaller paths. This divides the energy of the wave, sending it in many different directions which depletes its energy faster. Take a look at these diffusers available on Amazon. What do they all have in common?

Multiple Choice

Select the image below of the material that is most likely to be able to diffuse sound.

​Reflection -
Sound is bounced off a surface. This usually occurs on flat, rigid surfaces with a lot of mass like concrete or brick walls. Because the sound wave can't penetrate very far into the surface, the wave is turned back on itself like a ricochet. The sound bouncing back off the surface creates an echo.

Multiple Choice

Which of these images would be BEST at reflecting sound?

​Absorption - When a sound wave hit a particular surface, the kinetic energy driving it is converted into a small amount of heat energy which dissipates, leeching power from the sound wave and causing it to decaying faster. This is the kind of sound insulation provided by things like foam and rubber. How well a material absorbs sound depends on a number of different factors, including material density and how porous it is. In general, soft, pliable, or porous materials (like cloths) serve as good acoustic insulators - absorbing most sound, whereas dense, hard, impenetrable materials (such as metals) reflect most.

Multiple Choice

More dense materials are better at absorbing sound than less dense materials. True or false?

• True

• False