Damping
Sound deadening material is often used in the door cavities and boot/trunk area to damp excess vibration of the panels in the car in response to loud subwoofer bass tones, especially the boot/trunk. The most common type of deadening is either butyl or rubberized asphalt, a product which has an adhesive quality and can be applied by simply pressing it into place with a roller and using a heat gun (or hair dryer).
Other types of deadening include:
- Spray on Sound Dampening, less common because of the additional installation difficulties.
- Mass Loaded Vinyl
- Closed Cell Foam
Read more about this topic: Vehicle Audio, Common Components and Terms