Definitions for "SOUND TRANSMISSION CLASS"
a rating of the ability of building materials to stop the transmission of unwanted sounds. The rating is designed so that it expresses, as best one can with a single figure, the sound transmission loss in decibels when sound passes through the material. To determine the STC rating, test sounds of 16 different frequencies are transmitted through the barrier. The data is then smoothed to a standard contour using an established protocol, and the STC rating is the "smoothed" sound transmisson loss at a frequency of 500 hertz. Ordinary conversation can be understood through a window pane rated STC 25; a wall rated STC 50 stops all but the loudest shouting.
The rating that identifies the ability of an object to block sound.
A single-number rating system used to compare the sound-isolating characteristics of partitions used to separate occupied spaces. Assemblies are rated in terms of Sound Transmission Classifications. An STC value of 20-25 would indicate that even low speech would be audible in an adjoining room. An STC value of 50-60, on the other hand, would indicate that loud sound would be heard only faintly or not at all.
The average value associated with a material's effectiveness to reduce sound. The higher the value, the greater the reduction of sound.