Reverberation of Sound for Class 9 Students

Reverberation is the persistence of sound in a closed space due to repeated reflections from surfaces. Have you ever noticed that sound continues for a short time even after the source has stopped in a large hall? This effect is called reverberation. Understanding reverberation is important because it affects how clearly we hear sound, especially in large rooms and auditoriums. 

This article explains what reverberation is and how it can be controlled in a very simple way.

Table of Contents

• What is Reverberation of Sound?
• Effects of Reverberation
• How to Reduce Reverberation?
• Real-Life Applications of Reverberation

What is Reverberation of Sound?

When a sound is produced in a big hall, it does not stop immediately. Instead, it keeps reflecting again and again from the walls, roof, and other surfaces. Scientifically, it can be defined as, 

“The persistence of sound due to repeated reflections is called reverberation.”

Now, you may ask, what happens because of these repeated reflections?

The fact is, these reflections make the sound continue for a short time even after the source has stopped.

Effects of Reverberation

A small amount of reverberation may not cause much of a problem. But when it becomes too much, it creates difficulty in hearing clearly.

Have you ever noticed that in a large empty hall, words are not clear?

This happens because reflected sounds mix with the original sound. As a result, speech becomes unclear and difficult to understand.

So, excessive reverberation is not desirable, especially in auditoriums and large halls.

Now, the obvious question arises: can we control reverberation? Let's discuss in the next section. 

How to Reduce Reverberation?

To reduce reverberation, materials that absorb sound are used. These materials reduce the amount of sound that gets reflected.

The roofs and walls of auditoriums are covered with materials like compressed fibreboard, rough plaster, or draperies.

You might have seen curtains and cushioned seats in halls. These are not just for decoration. They help in absorbing sound.

So, using sound-absorbing materials helps reduce repeated reflections and makes sound clearer. 

Now, you may wonder, is reverberation always a problem? Interestingly! Reverberation can also be useful when controlled properly. 

Real-Life Applications of Reverberation

The fact is, reverberation is used in music to improve sound quality. In live shows and recordings, a small amount of reverberation makes the sound richer and more pleasant.

Moving ahead, let’s look at how this is done.

Different systems are used to produce and control reverberation. One such system is a chamber reverberator. In this, sound is produced using a loudspeaker and then picked up by a microphone along with the reflected sound.

Another example is a plate reverberator. Here, instead of a loudspeaker, a metal plate is used to create vibrations, which produce the reverberation effect.

So, in simple words, controlled reverberation is used to enhance sound in music and recordings.

So far, we have learned that reverberation is the persistence of sound caused by repeated reflections. We also understood that excessive reverberation can be reduced by using sound-absorbing materials in halls and auditoriums.