STC ratings are a way to measure and compare how much sound is stopped / absorbed by any given product / material. STC ratings are used for windows, wall assemblies, doors and some constituent materials.
The STC rating is the average amount of noise stopped at 18 different frequencies, measured in decibels. STC ratings are a logarithmic scale similar to the earthquake Richter Scale, which means each escalating number is significantly higher in performance than the previous number. It is a non-linear scale.See Post