Acoustic Windshield Performanceby Rick Waugh
Acoustic windshields come standard or as options on new cars. Acoustic windshields are layers of tempered glass, one on each side of a thin layer of polyvinyl butyral (PVB). The PVB layer reduces the amount of noise coming though the glass.
The primary purpose of an acoustic windshield is to reduce noise inside the vehicle. Pure tempered glass has little dampening, and has "coincident" frequencies that can actually react with and emphasize external noise. The layer of PVB dampens the sound; testing has shown reductions of 3 to 6 dB in the 1,000 to 5,000 hertz range. This is the frequency of the human voice, so conversations become easier to understand, along with the comfort of reduced wind and road sound.
Acoustic windshields can be made thinner than glass by itself. Weight savings of 3.5 lbs. are normal. Lower weight translates to less gas burned, meaning better mileage and lower emissions.
The layer of plastic between the sheets of tempered glass makes it more difficult to break in, as it provides a layer of elasticity between the glass plates.
PVB acts as a superior UV filter to plain, tempered glass. The result is less exposure to the driver and passengers to UV, and less damage to the interior of the vehicle.
- photo_camera classic sports car image by TA Craft Photography from Fotolia.com