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One of the hidden treasures of the car audio industry is sound dampening material. Not very many people know that such things exist, but they do and they may greatly improve the quality of your audio system. Various companies like Dynamat, Scosche, and Hushmat have available for you various sizes for different applications. You could either do your entire car or just spots that you know make a lot of noise such as door panels or the inside of your trunk.

How does it work?
Distortion and other unwanted noise occur when you simply drive on the road or when you are listening to loud music. It is cause by whatever surface you're driving on and that vibration is transferred through the mechanical movement of your tires, wheels, and suspension/strut system. When you are listening to loud music, your speaker or subwoofer causes certain part to vibrate in ways they would not normally move, causing rattles of many parts in your vehicle. In addition, your engine also contributes more noise and vibration; and the combination of all this noise gets collected inside your car and hampers the sound quality from being delivered at an optimal level.

Think of sound dampening mats as smaller-scale Tempur-Pedic mattresses for your car. You may have seen the commercial where disturbance on one side of the mattress will not disturb the other person on the opposite side. Dynamat uses the viscoelasticity property of the padding material to diffuse sound energy so that outside noise will not enter the vehicle or when applied on door panels for example, the vibration is greatly reduced or would not be heard from the interior. Sound is also kept within your vehicle and in so doing, keeping a much accurate sound inside rather than allowing it to escape.

The Improvement
As you could probably imagine, applying the mat would improve the sonic purity that your system produces. So imagine listening to music as loud as you want, without any rattles, distortion, or other outside noise. It will allow you to hear your music easier too so you won't have to always max out the volume.

Companies like Hushmat and Dynamat have reported outside noise reduction of up to 10 dB per complete application. Some vehicles could even have up to 20 dB noise reduction if properly matted and when using proper material. And because sound is also kept from escaping so easily out of your vehicle, you will find that your bass will also increase to about 3 dB in SPL.

If you want to improve the sound quality of your system in a cost-effective way, this is definitely a great way to do so. You could probably find plenty of affordable package deals out there like padding for two speakers for around 20 bucks or 360 square feet of padding material for around 40 bucks.

In the realm of car audio, the possibilities are endless. There are hundreds of brands and thousands of products out there. Majestic Modifications would like to help restore some order to the chaos of building your system. Lets look at some of the components that make up a car audio system.

The Head Unit

The Head Unit is the brains of the operation. Without this component, your car audio system can't and won't work. The head unit is the central processing device in the system. The head unit controls all the functions in your car audio system. Music too loud? Turn down the volume. Too soft? Turn it up. Want more bass? Add bass input. In addition to volume, bass, etc., the head unit may contain other systems within its casing. These include: tuner, cassette, equalizer, CD or amplifier.

You see, in a home music system, where you have much more room, many stereo setups will include a separate box for each one of these components -- CD, cassette, etc. You may have a home system like that yourself. In a car, with its space limitations, these components are often crammed into one box -- the head unit. This depends upon a number of factors, such as heat, space, cosmetic design and other concerns, and every car is different.

The Amplifier

All car audio systems have an amplifier, even if it's a small one. Occasionally the amplifier will be attached to the rear of the head unit; however, in most systems it is hidden elsewhere in the car to better dissipate heat. Signal amplification is actually a two-stage process, handled by two separate components. These are the preamplifier and the power amplifier.

The preamplifier (preamp, for short) is a very tiny signal coming directly from the head unit. Whether it's reproducing a cassette signal, a CD signal, or an FM broadcast, the preamp puts out a signal that the amplifier can use. This is where the power amplifier takes over. It's the power amp's job to take the signal from the preamp and boost it into the audible range. We'll cover this in more depth in our Amplifier column in this series. Again, because of heat, most amplifiers are located away from the head unit.

The Speakers

The speakers take the boosted signal from the power amp and create sound waves. Essentially, speakers transform electrical energy (the amplified signal) into mechanical energy (the motion of the speaker cone). For now, know that all sound is vibration, which is a chain of frequencies in the air that eventually vibrate the membranes in your eardrums. Sound energy is measured in wavelengths, known as hertz, with the audible range falling between 20 to 20,000 cycles. A cycle is the distance from the top of one wavelength to the top of the next.

There are three types of speakers that produce sounds across the audible spectrum: woofers, tweeters and midrange drivers. As the name implies, the woofer reproduces the lower frequencies. The tweeter, also aptly named, replicates the highest register. The midrange handles the frequencies in between.

Auxiliary Input Devices

Components such as CD changers and equalizers, not to mention cell phones, navigation systems, MP3 players and many of the newer technologies, interface with the head unit for amplification and signal processing.

With a little knowledge of car audio components, it's time to start searching for your own car audio system!

Most speaker boxes are either fiberglass mat, or MDF construction. MDF while easy to work with and achieve good results, lacks the custom touch. Fiberglass allows you more freedom to do what you want. In this guide we are are building a simple box to show the process of working with speaker rings and glass mat. Many of the same steps apply for a built in sub woofer box.

Start by cutting out a MDF base for your new enclosure. If you are building a built in box, this does not apply to you. Once you have your base, you need to figure out how you want to aim your speaker. How you aim them depends on the type of speaker and personal preference. Once you know how you want to aim the speaker you can start cutting and gluing dowels to hold the speaker rings in the correct alignment. These dowels only need to be strong enough to hold the rings until your first resin application dries. Make your enclosure the correct size to meet the volume needs provided by the speaker manufacturer.

Next using hot glue or stables wrap your form in either fleece or cotton. While fleece is the preferred fabric, I like to use cotton. Cotton will soak up less resin which makes for a stronger lighter box.

With the fabric stretched tight you can apply the first layer of resin. In this step you do not use glass mat. You are just trying to get the fabric to retain a shape you can work with. For resin, I recommend a cheap poly based resin. There is no need for more exotic epoxy resins as the resin will not see high stresses or UV. In any case, you should follow the resin manufactures instructions for mixing and working in only a well ventilated area. If you have experience with fiberglass you can add up to 50% more hardner to speed cure times. Any more than 50% compromises strength and creates too much heat.

Now that you have a rigid form you can begin building your mat layers. I suggest the heavy weight mat used by marinas for boat hulls. The heavy weight mat is both inexpensive and strong. Mix enough resin to lay down 3-4 pieces of mat that are 12"x12". You can cut down a large paint brush to apply resin and stab out air pocket. Another method is to use a fiberglass roller. No matter what method you use keep you tools in paint thinner between coats to prevent them from becoming un-usable. Keep applying mat and resin until the enclosure is complete and sturdy. A good gauge of when the box is strong enough is when it can support your full weight.

Once the sub-woofer box is strong enough to support your weight, completely sand it with 80grit sand paper to provide a good base for the auto-body filler you will apply.

The key to applying auto-body filler, is use thin coats and more coats than you think you need. You will need to sand between coats to prevent de-lamination. Whenever sanding use a quality dust mask.

Keep applying and sanding off the filler until all major holes and dimples are filled. Now is the time to install any speaker terminals or brackets you need to complete your install. I also take this time to remove any dowels that have become loose. For any I cannot remove, I simply mud them in place to prevent them from coming loose later.

If you plan to carpet your enclosure you can stop at this point. If you are going to paint it you need to apply a glaze coat to fill any pin holes and minor dimples left. After the finish is defect free sand from 120 to 600 grit sandpaper in preparation for primer and paint. From here you have a wide variety of choices from lacquer paint to Rhino-Liner.

To get the loudest and best sound quality from your car's stereo system, you will need to add an amplifier to the system. As good as after market head units are, they just don't produce enough power to give you great sound at higher volumes. Here are some tips for adding an amplifier to your car stereo system.

Amplifiers can take the signals from your head unit and give you a much more powerful, cleaner signal to power your cars speakers. When adding am amplifier, it is important to know your speakers limitations. Most factory speakers won't do well with an amplified signal, so you will want to upgrade these as well in a lot of cases. Look for the ratings of continuous power or RMS ratings. These ratings will give you the best indication of how much power the speakers can hold. Match this rating to the amplifier rating to ensure you are getting everything out of the system, and that you will have a system that will be durable and last.

The signals the speakers receive should also be taken into account. Larger subwoofers need the frequencies on the lower end to produce the bass tones, but you wan to be sure to exclude frequencies that are above, and below, the recommended range. Too low and you risk damaging the speaker, and too high can cause some undesirable results sound wise. Most amps are quipped with a subsonic (too low of a frequency) filter to avoid the low frequencies. They also have a crossover that will eliminate the higher frequencies as well. These two components allow the speaker to get the frequencies it needs for optimum performance.

Smaller speakers should also be set up to get the frequencies they need. If amplified, these speakers almost always should have a crossover attached to ensure that big bass tones won't damage the speakers designed for midrange response and high frequencies. Dividing the sound into low, middle and high frequencies using the different types of speakers creates a medley of tuned sound that gives the experience we want from our systems.

Pay attention to ohms and power ratings, and be sure to match all accordingly. Combining multiple speakers on one channel always affects the ohm rating of the system, and can be detrimental if the system is not designed for it. Subwoofer amplifiers tend to be more forgiving due to their low impedance (ohms) ratings and flexibility. Remember, it is the combination of power and precision that make the system sound the best.

To get the loudest and best sound quality from your car's stereo system, you will need to add an amplifier to the system. As good as after market head units are, they just don't produce enough power to give you great sound at higher volumes. Here are some tips for adding an amplifier to your car stereo system.

Amplifiers can take the signals from your head unit and give you a much more powerful, cleaner signal to power your cars speakers. When adding am amplifier, it is important to know your speakers limitations. Most factory speakers won't do well with an amplified signal, so you will want to upgrade these as well in a lot of cases. Look for the ratings of continuous power or RMS ratings. These ratings will give you the best indication of how much power the speakers can hold. Match this rating to the amplifier rating to ensure you are getting everything out of the system, and that you will have a system that will be durable and last.

The signals the speakers receive should also be taken into account. Larger subwoofers need the frequencies on the lower end to produce the bass tones, but you wan to be sure to exclude frequencies that are above, and below, the recommended range. Too low and you risk damaging the speaker, and too high can cause some undesirable results sound wise. Most amps are quipped with a subsonic (too low of a frequency) filter to avoid the low frequencies. They also have a crossover that will eliminate the higher frequencies as well. These two components allow the speaker to get the frequencies it needs for optimum performance.

Smaller speakers should also be set up to get the frequencies they need. If amplified, these speakers almost always should have a crossover attached to ensure that big bass tones won't damage the speakers designed for midrange response and high frequencies. Dividing the sound into low, middle and high frequencies using the different types of speakers creates a medley of tuned sound that gives the experience we want from our systems.

Pay attention to ohms and power ratings, and be sure to match all accordingly. Combining multiple speakers on one channel always affects the ohm rating of the system, and can be detrimental if the system is not designed for it. Subwoofer amplifiers tend to be more forgiving due to their low impedance (ohms) ratings and flexibility. Remember, it is the combination of power and precision that make the system sound the best.