Suppose your class invites a person to give a speech. When you test out the sound system in the gym you find there are so many echoes the speaker cannot be understood. What needs to be done to fix this problem?

You either need to lower the volume so the sounds intensity is lessened. Or you can pad the walls to absorb the sound rather than defect.

Explanation:

Sound intensity allows it to be heard further, but in an enclosed room it will start returning. Sound will deflect off of hard objects do to its interactions with solids. A softer and foamy material can dampen it.

electromagnetic shielding is the practice of reducing the electromagnetic field in a space by blocking the field with barriers made of conductive or magnetic materials. shielding is typically applied to enclosures to isolate electrical devices from their surroundings, and to cables to isolate wires from the environment through which the cable runs. electromagnetic shielding that blocks radio frequency electromagnetic radiation is also known as rf shielding.

the shielding can reduce the coupling of radio waves, electromagnetic fields and electrostatic fields. a conductive enclosure used to block electrostatic fields is also known as a faraday cage. the amount of reduction depends very much upon the material used, its thickness, the size of the shielded volume and the frequency of the fields of interest and the size, shape and orientation of apertures in a shield to an incident electromagnetic

from wikipedia