What are STCs and IICs and how do they work?
STC (Sound Transmission Class) is a measurement that indicates how much noise is stopped (absorbed) by the wall or floor ceiling assembly (airborne or voice noise). IIC (Impact Insulation Class) is a measurement that indicates how much impact noise is stopped in a floor/ceiling assembly. STC and IIC are logarithmic, like the Richter scale. Each 10 points represents a doubling of the noise reduction capacity of an assembly.