STC (Sound Transmission Class) is a rating that describes how well a building material or assembly blocks airborne sound. A higher STC rating means less noise will pass through the material, providing better sound reduction. This rating system applies to various building components, including windows, doors, flooring, drywall, and insulation.
For context, a typical single-pane window has an STC rating of around 25 (where normal conversations are audible), while a well-sealed, double-pane window can exceed STC 45 (blocking loud speech and most music). It is important to note that for some products, like soundproofing drywall, the STC rating refers to the entire wall system, not just the individual panel.
Additionally, STC ratings are most effective for measuring sound reduction at mid-to-high frequencies, such as human speech, and may not accurately reflect how well a material blocks low-frequency sounds like bass music or thunder. Because of these factors, it is recommended to consult a professional to determine the right STC-rated materials for your specific soundproofing needs.
