What is sound insulation?
When the sound wave hits a partition, one part of it is reflected from the partition surface and then is transmitted to the opposite side of the room, and the other part is absorbed by the partition. The reflected part stays in the same room as the source of sound.
There is a clear difference between a barrier and an absorption coating. The usual barriers made of rough and solid material can intensify the reflection of the sound waves in the room while isolating coatings let the sound through without any obstacles.
In other words, you can’t use barriers for sound absorption, the same as you cannot use sound insulating materials to prevent the escaping of sound.
Sound insulation rate is a conventional figure, which defines sound insulating characteristics of construction elements separating one room from another.
Also you can expect that an insulation rate will be 5-10 Db lower than the corresponding lab based sound transmission rate of the same product.
The explanation is as follows: most of the modern constructions are built not as well, the floors and walls are not as flat, the joints are sealed not as qualitatively and the materials are not as thick as in the objects tested in laboratory environment, which always have excellent properties.
That is why at the early stages of a project a construction agency should consult independent specialists on the matter of acoustic properties of constructions, even for getting recommendations.
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