Specular and diffuse sound reflection

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Gif_Reflexión especular y difusa del sonido.gif

Greetings again my dear friends of this prestigious platform, for no one is a secret that around us a lot of phenomena are developed and among them we find the sound and in turn other intrinsic phenomena when it propagates through any material or elastic medium such as air, solid or liquid, therefore, we will relate on this occasion with the diffuse reflection of sound.


Any of us can express that our auditory senses are constantly in a permanent process of capturing some kind of sound in our environment, and such sound, of course, originated by the vibration of certain component particles of an object or body that emits such sound, and this phenomenon can be found originating from artificial or natural sources such as the vibration of our vocal cords.

We often hear about the frequency of sound and it represents the number of waves that manage to pass in one second through a given reference point, where we implement as a unit of measurement the hertz or Hertz (Hz).

As we have expressed there are several intrinsic phenomena that originate when the sound goes from one side to another, such as reflection, and the same, can be both specular reflection and diffuse reflection, and the latter will be discussed in general in this article, highlighting that such phenomena are carried out when the sound is on its way with various obstacles.

The above reflections will depend on the surface on which the sound waves impact, for example, when the sound rays impact with a flat surface we see the formation of two equal angles, that is, the angle of incidence and the reflected, and these characteristics determine a specular reflection as we can see in the following.

Figure 1. Specular reflection of sound waves


In the previous figure we can see the behavior of sound waves on a flat surface, however, the opposite occurs when we talk about diffuse reflection and we will talk about it below.

Diffuse reflection

When we relate to this type of sound reflection it is important to take into account the description of a smooth surface because the type of reflection to be taken into account will depend on it, then, it is necessary to relate the wavelength of the emitted sound with those asymmetries or irregularities of the surface with which these waves strike.

In relation to the above, we can say that if the asymmetries or irregularities are smaller than the wavelengths of the sound, then a diffuse reflection will hardly occur, since the surface can be considered as smooth or flat, and with this, we would have a reflection similar to that of figure 1, i.e., specular.

When we find surfaces whose irregularities or asymmetries are equal to or greater than the wavelengths of the emitted sound, we would be observing a diffuse reflection of the sound waves as shown in figure 2 below.

Figure 2. Diffuse reflection of sound waves



Our environment is full of any kind of phenomena such as the essential sound that we can capture through our natural auditory systems (ears), and hence the importance of being able to understand any knowledge related to these essential phenomena so important for our existence.

Sound, like light, is affected in its propagation when it encounters any type of obstacle in its path, and this is very frequent since we are surrounded by a large number of bodies or objects that in one way or another affect the normal propagation of sound from one space-time to another.

In this opportunity we analyze in a general way the phenomenon of sound reflection either in a specular or diffuse way, and this characteristic depending on the geometric shape and irregularities of the surface with which these sound waves impact as you could observe in figures 1 and 2.

Until another opportunity my dear friends.

Note: The images are my own and were created using Power Point and the animated gif was created with the PhotoScape application.

Bibliographic References

[1]Física del sonido

[2] Reflection and Transmission of Sound Waves..


Wow... fantastic write up. You made me to remember what i have learnt in the past when we are growing up in physics...