Automobiles are noisy things. Not only is there outside noise to contend with, your typical car –which is essentially a big, resonating box- generates plenty on its own. Automotive engineers, of course, have known this for a long time and have developed plenty of noise-deadening materials and techniques to quiet things down. Most of these techniques are rather simple, though. They include filling up body cavities with acoustic foam and gluing tar-like acoustic materials to the inside of car doors. Undercoating provides a measure of noise protection also.
Today, however, there is another technique being used by car designers. It’s called Active Noise Cancellation. Though it’s been around for a while, Active Noise Cancellation (ANC) is just starting to be used in cars. It’s a very cool technology and is basically the wizardry behind the popular Noise Cancelling Headsets being sold by BOSE Corporation and others.
The way that ANC works in cars is that small microphones in the interior pick up the sounds of the engine, wind and other noises. The system then takes these sounds and develops a counteracting signal which gets fed it into the car’s audio system to “remove” the noises. Dealers tell us the result is an eerily-quiet car interior that allows music and other sources to be enjoyed like you’ve never heard them before.
However, making a car quiet takes more than just noise cancellation technology. Buick, for example, combines ANC with other more traditional techniques to form their QuietTuning™ package. This package utilizes high tech sound dampening materials, tuned to specific sound frequencies, throughout the automobile interior. In addition, windshields are acoustically laminated and the side windows are made from a thicker 5mm glass. Even the tires are specifically chosen for their ability to keep the noise down.
An interesting “note” (pun intended) to consider is that Active Noise Cancellation can be fine-tuned to actually allow a little more exhaust noise outside the car as this is often desired by those that want sports cars. Team Nissan in Manchester, NH explained that the Nissan flagship sports car, the GT-R Sports Coupe, produces a wonderful exhaust tone outside the car but is almost silent inside the cab due to ANC. How cool is that!