There are various forms of sound deadening materials on the market current. Every from spray on to peel and stick products. For this article we will focus on the peel and stick product that comes in sheets and is applied with an adhesive on the back of the sheet. This deadening is more difficult to work with, but much more effective than the spray-on type. It is usually used on larger areas, or where more deadening is needed.
Sound deadening can be an expensive thing to do but a smart installer will advise on the best possible application to ensure you get the best value for your investment. How to begin
The easiest way to determine where to apply the deadener is also the simplest. Take you car for a drive with the radio off. Now carefully listen to where most of the noise in the vehicle comes from. The most common areas are around the wheel wells, the firewall area, doors, roof and the boot of the vehicle. Most modern vehicles have fairly good carpeting installed but the floor of the vehicle can still be a source of noise.
Now make a list of these areas and decide which are the most important to you. This should give you a good starting point with your installer. Discuss with him what you have experienced as well as your budget and work from there. The installer will be able to tell you how much product you will need. Personally I recommend starting with the doors and then repeat the above process afterwards. Careful though. Sound deadening can be addictive.
Once you have sorted out the doors go for another drive. This time turn on the radio and see how much of a difference the deadening has made to the overall quality of the system. Now there is a good chance that you will find some rattles you havnít noticed before. Its a good idea to get a little extra deadener just incase you need to bulk up on certain areas. What else does sound deadening do?
Apart from the obvious silencing of road noise, sound deadening also help to a great extent in reducing panel vibrations in a vehicle. A good example of this when you upgrade the door speakers in your vehicle. The original manufacturer never intended for the vehicle to be equipped with high power drivers so the panel has not been designed to accommodate the extra power from the speaker and is therefor prone to vibrating and flexing due to induced resonance from the speaker. By adding sound deadener to this panel you effectively add mass to the panel and in turn reduce the resonant frequency of the panel. The speaker will now perform better thanks to the additional weight of the panel and reduced vibrations in the panel.
The quickest way to fix this issue is to just cut out a ring of sound deadening material and applying it to the area where you mount the speaker. Make sure the baffle and speaker is bolted down properly. Now have a listen to the system again. You should hear an immediate improvement. If the difference is not noticable try applying more deadener around the speaker and the baffle it mounts on. Each additional piece of deadener will add mass to the panel.
You might now notice that the door panel itself (plastic outer panel) is buzzing or vibrating when the midbass driver plays lower frequencies. Its a good idea to apply sound deadener on the inside of the panel. You donít have to cover the whole panel either. Just add pieces to the biggest flat areas of the panel to add some mass. Keep adding and testing until you find the buzzing is no longer audible. Moving on
Once you are happy with the doors you can move onto other areas of the vehicle. The next logical area to deaden is the boot of the vehicle followed by the wheel arches. Doing the boot will reduce a lot of road noise and help to increase sub bass response if the vehicle is fitted with a sub woofer.
I really hope this first installment in the art of sound deadening will be helpful. In our next article we will do a quick tutorial on how to apply the deadener to the door itself and how the speaker baffle should be treated to ensure the best possible response from the speaker.