Do-It-Yourself/Upgrading your car audio

Introduction
Unless you have a very expensive car, your car probably came with a sub-par stereo system. It probably distorts at louder volumes and does not have the bass and clarity that you desire. The purpose of this manual is to describe what steps need to be taken to upgrade your car's sound system.

Target audience of this wikibook
This manual assumes that the reader knows nothing or little about this subject. The majority of advice given in this manual applies to common cars available in North America, such as American, Japanese, and German vehicles. The information may or may not be applicable to vehicles sold on other continents or by other manufacturers, such as Indian or Chinese manufacturers, as the author has no familiarity with them. The information also may not be applicable to very old vehicles. It would be helpful to one's understanding if s/he had knowledge of basic woodworking, fiberglass, and/or electronic components.

The Head Unit
The head unit is the actual stereo itself. It is the main part of the entire sound system and is probably the only part that you as the listener will interact with.

Why replace the head unit?
You may want to replace your head unit for several reasons:
 * it may not have all the features you want, for example it may not be able to play MP3s
 * it may be low quality, for example CDs may skip, or the sound clarity may be low
 * it may not be able to provide enough power to the speakers
 * The aesthetic features may not be ample

How to replace the head unit
The first step in replacing the head unit is obviously to pick out a new one. They may be purchased in stores which cater specifically to car audio, or they may be purchased in stores such as Best Buy or Circuit city. Another option is eBay. There is much debate about which brand is the best to buy, and if you ask ten different people you will probably get ten different answers. Some people advocate a single brand which they have had good experience with, while other people claim that the brand is not very important. It is up to you to decide which model to buy, after having done sufficient research on it on the internet. A good place to research is to look for reviews written about the model you are interested in, or visit audio-related forums.

The next step is to remove your factory head unit. This will probably involve unscrewing a portion of your dash, and while it's not rocket science it can be challenging on some vehicles. For example, most Ford vehicles have four small holes on each corner of the stock head unit. Using special pins that you can purchase at any car audio or parts store for about 7 bucks, makes this removal extremely simple, but without them it becomes fairly difficult. Every vehicle is different and a single manual cannot provide step by step instructions for every vehicle, but you should be able to find the appropriate instructions on the internet. After the dash has been removed, you have access to the head unit. Unscrew the screws holding the head unit, and pull it out, disconnecting the wires that connect it to your car's power supply and antenna.

Next you need to put your new head unit in. This requires some extra equipment. First, you need a mounting bracket. Your new head unit may not be the exact same size as your old one (1985-1995 era Ford cars [Tempo, Escort, etc] have stock head units the same size as aftermarket ones), and the screw holes may not be in the right places. A mounting bracket is necessary to mount the new head unit in place, and cover the extra space if the new head unit is smaller than the old one. Secondly, you will need a wiring harness. A wiring harness connects your new head unit to your vehicle's power supply. Thirdly you will also probably need an antenna adapter. The store which sells you your head unit will probably know which wiring harness and which antenna adapter your vehicle requires. If they do not a car audio store should be able to help you.

Finally, put your dash back together and you are done.

An alternative is to have the store install your deck themselves. This will probably cost about $30 in the US. Some stores offer free installation on sufficiently expensive decks.

The Speakers
Factory speakers are usually of very poor quality and replacing them with aftermarket ones will result in an enormous improvement in sound quality.

Most vehicles have four speakers, but some have six, eight, or even twelve. In this author's opinion, more speakers does not necessarily amount to greater sound quality and manufacturers only put more speakers in cars so that car buyers will think "Wow, this car has 8 speakers, it must be a lot better than a car with only 4!". Four high quality speakers will produce superior sound to twelve poor ones.

Replacing the speakers is a relatively simple process. Your front speakers are probably in the front doors, or in the dash, or both if your car has more than four speakers. Removing the door speakers requires removing the door panels. if you open your door and look around it, you will notice screws holding the door panel in place. Removing all of the screws will loosen the panel. If your car has manual window cranks, you will need to remove those in order to get the door panel off. Once the door panel is off, you have access to the speaker. Remove the screws holding the speaker, disconnect the wires, and connect the wires for your new speaker. Secure your new speaker with screws, and screw the door panel back on, and you're done. You will have to unscrew other portions of your car in order to get at the speakers in the back, or speakers in your dash, or wherever else they might be in your vehicle. It is impossible for a single manual to provide detailed instructions for every single vehicle, so you will have to research on the internet if you cannot figure out how to remove the speakers.

Note that replacing only your speakers and nothing else may not necessarily result in a major improvement in sound quality. This is because your head unit may not be able to provide the necessary power to power your speakers to their full potential. A typical head unit may provide a total of 200 watts of power. When divided by 4 speakers, that is only 50 watts per speaker. If your speakers can handle a maximum of 150 watts each, then you are not using them to their potential. The way to solve this problem is to use an amplifier.

The Amplifier
An amplifier is a device which provides more power to your speakers. In some cases, replacing only the head unit and speakers will provide a sufficient improvement in sound quality to satisfy you. But other times the head unit will not provide enough power to the speakers, and an amplifier is necessary. Amplifiers range greatly in price depending on how much power they can provide. An amplifier can be found to produce from as little as 50 watts up to 4000 watts, they can often be split into more than one 'channel'. For example, if a 1000 watt amplifier is purchased, and the desire is to use it to run two speakers, the amplifier often has the capability to split the power in half and supply to each channel. Thus, the 1000 watts is suddenly split into 500 watts on the left channel and 500 watts on the right channel.

Amplifiers work by taking power directly from the vehicles battery, (12 volts DC), through a 'power line' which has a fuse (varying in capacity), directly to the amplifier. The amplifier is then grounded out through a separate wire of similar gauge to the power line, into the body or frame (or other appropriate metal area) of the car. A 'remote' wire, coming from the back of the head unit, tells the amplifier to turn on anytime that the head unit itself is powered up. For the signal, or sound energy, there is (most often) one or more 'RCA' jacks coming from the back of the head unit, which then connect directly to the amplifier. RCA wires are the same wires that you find color coded on the back of your dvd player.

The Subwoofer
A subwoofer is a large speaker intended to play all the low frequency sounds, and produce bass. If you want very deep bass that will shake your car, a subwoofer is a must. Subs come in a range of sizes, the most common being 6, 8, 10, 12, or 15 inches. MTX Audio Corp. has developed a 22 inch sub, weighing nearly 350 pounds. The power required to run a sub increases as the 'cone size' of the sub is increased. The power rating of a sub can be seen often on the package that the speaker is bought in, however, this is often the "maximum" power rating, meaning that the power advertised is the point at which the speaker will fail or sound distorted. 'RMS' power rating (root mean square), is the power that is recommended to be used for the best audio quality from your speaker, and is also found either on the package or on the speaker itself (magnet or cone). Subs require a "box" (usually wood or fiberglass in design), and an amplifier of sufficient power to sound optimal. The sub is placed into the box of the appropriate dimensions, connected to the amplifier via the 'terminals' on the voice coil of the subwoofer (which are then connected to terminals on the inside of the box, and then led outside the box via the same terminals on the other side). The sub is screwed down and/or sealed in by silicone. The box is most often placed in the cargo area of the vehicle (cars and SUV's) or behind the seats in trucks. Special boxes can be bought or crafted for a particular fit behind a seat or against a wheel well in a trunk.