Explained - STC Rating

Explained -  STC Rating

STC is an acronym for Sound Transmission Class. It is described in terms of a representative number that rates how well a room or material will insulate acoustic sound pressures such as speech, music or other.

Below is an example of the perceived audible changes for increment STC ratings for wall or room soundproof treatment.

There are several material available to increase STC rating  

STC Rating of the Soundproofing Material

30-35   Clearly intelligible speech

36-40   Only 50% of speech is intelligible

41-45   Loud speech audible, music and TV’s heard

51-55   Speech not intelligible, loud music and TV heard

56-60   Loud speech not heard, music significantly muffled, bass still heard

61-65   Music barley heard, bass still heard, power tools heard

66-70   Most airborne blocked though very loud music and power tools still heard though structure transmission.