Sound proofing/deadening is one of the most over looked aspects to car audio. When making a vehicle quieter you have three fundamental ways of stopping the unwanted noise reaching the cabin and your ears:

1 – Stop Vibration

Noise from the vehicles engine, tyres and general road noise can make the metal panels vibrate.These vibrations are amplified by the resonating panels essentially turning your vehicle into a giant speaker.By applying a sound deadening mat to the metalwork the vibrations will be damped and the vehicle will seem instantly quieter

2 – Absorb Sound

Once these vibrations have been killed you need to deal with the airborne noise that is still coming through the doors and floor etc.  It is only practical in a vehicle to absorb the higher frequencies therefore a range of foam products are applied on top of your damping mats and to fill hollow voids eg roof void etc.   (These foams are also excellent at isolating trim panels that may rattle or squeak)

3 – Block Noise

Low frequency road and exhaust noise cannot effectively be completely absorbed in a vehicle as the thickness of foam required would be impractical. It is therefore required to block the incoming noise with an effective barrier. The best solution in a vehicle is to use a heavy vinyl layer (MLV).