Sound insulation or sound proofing is used to indicate the reduction in the level of sound when it passes through a building component. Sound insulation and sound absorption are quite different terms. The purpose of a sound-insulated construction is to prevent the sound from passing through it. Hard materials in general are poor sound absorbers but they are good sound insulators.
The purpose of a sound absorbent material is to reduce the sound reflected from a surface. Hence, porous materials in general are good sound absorbers, but they are poor sound insulators.
Insulation of sound is measured in an adjoining room while absorption of sound is measured in the same room.
Table 6.4 shows the desirable levels of sound between individual ...