Acoustic Terms and Definitions: Sound Transmission Class or STC
Sound Transmission Class or STC is an integer rating of how well a building partition attenuates airborne sound. In the US, it is widely used to rate interior partitions, ceilings, floors, doors, windows and exterior wall configurations. The higher the value, the better a structure is at reducing airborne sound. For example, STC rating of 60 indicates good soundproofing - most sounds will not disturb neighboring residents.