OK, here's the deal: If you want to build a quality stereo system, SOUND DEADENING IS NOT OPTIONAL; IT IS MANDATORY.

Why is that?

Let me ask you a question: Do you want to hear music, or road noise? Do you want your license plate to be quiet, or rattle when the bass hits? Do you want to hear your tires, or do you want to hear MUSIC?

I know I want to hear the music, and as such, I never do a real car stereo installation without using sound deadening material.

So, with all of that said, let's take a closer look at sound deadening.

Sound deadening comes in many forms, but the two main types are spray on, and matting.

Spray on deadening comes in either an aerosol spray paint can or in a large bucket. The aerosol can is great for small jobs, but if you plan to go crazy with the deadening, you'll want to buy it in bulk. When you buy it in bulk, you'll also need a nozzle of some sort. Usually this can be purchased with the large bucket of sound deadening. This type of sound deadening material works best for tight areas, and where you want a medium amount of sound deadening.

The other kind of sound deadening 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.

Because sound deadening can get expensive, the smart installer installs it where it is most effective. To figure this out, take a drive in your car with the radio off. Listen to where the most noise comes into the vehicle. The main places I look to deaden are around the wheel wells, the firewall (of course), the doors, the roof of the trunk, under the rear seats, and under the center console.

SO! Check out those places, check out any other place where noise comes through, and start figuring out how much material you'll need.

This rule should go without saying, but get more material than you think you'll need. The reason for this is because once you have the material installed, you'll want to do a second listening, only this time with the music turned on. You will most definitely find rattles that weren't noticed before. You will probably also find some places where you'll want to bulk up on sound deadening.

When reproducing music, noise and distortion are your biggest enemies. Sound deadening will go a long way towards fixing these problems.

In addition to silencing road noise, sound deadening works great for reducing rattles in your vehicle. For example: Say you just mounted some high powered speakers in your doors. Because vehicle manufacturers never intend for high powered speakers in the doors, they aren't designed to handle the vibrations.

To fix the vibrations (which sound HORRIBLE), just cut out a ring of sound deadening material, and apply it to the spot where you mount the speaker. Mount the speaker to the top of the sound deadening material, and be sure the speaker is bolted down tightly. Now, try turning up the stereo again. Did this fix the problem? If not, try applying another layer of sound damping material.

Another trick: Have you ever noticed that certain panels in your vehicle vibrate when certain bass frequencies play? Get some of the spray-on sound deadening material, and apply it to the back of the panel to dramatically decrease the vibrations. For larger panels, use sound deadening sheets.

Another trick: Does your license plate rattle when the bass hits? Don't look like an idiot, fix it! Take some sound deadening material, and apply it to the back of the license plate and the license plate frame. Try the bass again, only this time you won't embarass yourself when you drive through a parking lot!