Ans. ACOUSTICS PROTECTION
The technique or method used to absorb undesirable sounds by soft and porous surface is called acoustic protection.
Importance of Acoustic
Reflection of sound is more prominent if the surface is rigid and smooth, and less if the surface is soft and irregular. Soft porous materials, such as draperies and rugs absorb large amount of sound energy and thus quiet echoes and softening noises. Thus by using such materials in noisy places, we can reduce the level of noise pollution. However, if the surface of "classrooms or public halls are too absorbent, the sound level may be low for the audience.