How to Build Your Own Custom Car Entertainment System

Let's be honest: Unless you buy a car that has an expensive, brand-name factory stereo option, your standard speakers probably aren't going to be anything to write home about. Speaker upgrades are a basic and fundamental way to get your car custom sound system started, and probably the easiest way to get immediate, better audio quality in your vehicle.

You'll want to measure the speakers that came with your car to make sure you buy the right size and shape. For instance, most typical front speakers are four, five or six inches (10, 13 or 15 centimeters) across, while most rear speakers measure 6 by 9 inches (15 by 23 centimeters).

There are two types of speakers to consider: coaxial and component. Coaxial speakers are the cheapest and most common models. They integrate midrange sound by incorporating a woofer (for low range sounds) and a tweeter (for high-pitched sounds) into one unit. These speakers are easier to install, but generally produce lower sound quality. You can put speakers like these into your doors or the rear deck -- the area just below the rear glass -- by swapping them out with the originals.

Component speakers are a set of multiple units -- including both woofers and tweeters -- installed at different locations throughout the car, each one producing its own sounds to give a kind of concert quality to your music. These are typically more expensive than standard car speakers and installing them is often much harder, too. In fact, you may end up needing a jigsaw to cut a hole in your A-pillar (where the front door meets the windshield) to install the tweeters [source: Crutchfield]. Then of course, there's the infamous subwoofer. If you want that throbbing, thumping bass that can be heard (and often felt) from several yards away, you'll want one of these in your car. Subwoofers provide that deep, low-end bass and are often installed in the trunk or rear compartment of the vehicle.

Above all, listen to the speakers you want before you buy them. Do they produce the quality you're searching for? Do they suit the type of music you like? Only you can tell what speakers are best suited to your ears, so take them on a test run before you make your purchase.

Speakers are great, but without a receiver to play music, they don't do much. In the next section, we'll talk about the latest in receiver technology and how today's radios do much more than just play music.

When it comes to being entertained in your car, there have never been more options available as there are today. So what exactly do you want to do? Look at maps, listen to your MP3 collection, or watch a movie on DVD? If you've got the cash, you can do all of the above.

A good place to start when you want to bring your audio dreams to life is a car receiver -- also known as the stereo or head unit. A new receiver can have as many features as you're willing to pay for. Basic receivers provide you with CD playback and often feature colorful graphics. But for a little more, you can get one that plays MP3/WMA files or has an auxiliary input for your music player. In addition, you might also consider a satellite radio receiver for your car. This gives you a lot more audio options, but be mindful of what it costs to subscribe.

If you're always getting lost on the road, it may make sense to get a receiver with a built-in navigation system. On newer cars, these are optional and sometimes even standard car equipment, but really any car can be retrofitted with one. A typical in-dash navigation system is made up of a car stereo with a small built-in car monitor, a connection unit with audio and video inputs and outputs and an external GPS antenna [source: Crutchfield]. These can cost more than $1,000 in many cases, but they have that great "from the factory" look and boast a number of other features, like being able to locate ATMs or restaurants in your area. A more portable unit is a less-expensive option.

So what's the ultimate in-car receiver? For now, it may be the DVD receiver. These have extra-large LCD screens and when you aren't playing DVD movies with them, they have impressive displays to control your car's audio and other features. Bluetooth, iPod connectivity and satellite radio can all be controlled from such a receiver and some also include GPS navigation. If you really want to get high-tech, some even include a rear-mounted camera to make backing up much easier. You can also connect a rear monitor (or monitors) to entertain your passengers in the backseat.

One thing to keep in mind is the cost, because a DVD receiver can be a big investment. You can expect to pay several hundred dollars for a good one, not to mention the cost of installation and extra monitors. Be careful, as it can all add up quick.

Up next, we'll discuss amplifiers -- because all this equipment is no good if it's not getting enough power.

Let's say you've invested in a new set of upgraded speakers and a sleek new stereo receiver unit. You're on your way to hearing your music in superior ways. However, your car may not be doing your custom audio system justice -- and your radio's built-in amplifier might not supply enough power to the new components.

This is why you might need an external amplifier, or amp, as your audio setup becomes more and more elaborate. Amplifiers take a signal from the stereo and use an independent power source to change it into a more powerful signal for the speakers. The more power the amplifier delivers, the cleaner the sound from the speakers. Granted, most aftermarket stereo units have at least twice the power of a stock radio, but in many cases, it's simply not enough [source: Consumer Guide]. If you're going to have a bunch of subwoofers and component speakers in your vehicle, an amp is probably a good idea.

In most cases, you'll want one amp for all the speakers in the car, which means you'll need multiple channels on the amp -- each channel drives one speaker. Since most cars have four speakers, four-channel amps are the most popular. Five- or six-channel amps will give you even more options. If you only have one subwoofer and no other high-powered speakers, you only need a one-channel amp. Otherwise, the subwoofer will probably require its own amp.

It is important to match up your stereo and speakers with the right amp. You'll see two power ratings when shopping for a car amplifier: root mean square (RMS) power, and peak power. Here's what they mean:

It's important to make sure the RMS number on your amp matches the rating on your speakers. If the numbers don't match, your speakers could be underpowered, or even overpowered. If they're overpowered, they have the potential to overheat and become damaged.

So now that you've bought all this great equipment, should you have a professional install it or do it yourself? In the next section, we'll weigh your options.

The next big piece of the puzzle is figuring out how to fit all of your new audio equipment into your car. Getting a set of good component speakers installed professionally will cost you around $80 or $90, and a four-channel amp installation will cost around $100. An in-dash stereo with a screen, like a DVD receiver, could go as much as $200 [source: Geek Squad].

That's a lot of money, and you've likely already spent quite a bit on purchasing the equipment. That's why installing it yourself might be a good way to go. It's entirely possible to do it all yourself, as long as you have the proper tools, wiring diagrams, and instructions. Depending on what you've purchased, it may also entail a significant time investment.

One very important point to remember: Always disconnect the negative connection on the car's battery before you do any type of work to avoid shocking yourself or damaging your new equipment.

Installing coaxial speakers is fairly simple. These involve removing the front or rear factory speakers and simply swapping in the new ones while making sure the wiring is correct. Component speakers are a bigger job. Since you're going to be putting multiple new parts in your car, like tweeters and woofers, this could involve some cutting or drilling into the doors or A-pillars. In some cases, you'll need to be able to take apart your car door to accomplish this. The job may also involve some soldering [source: Crutchfield]. In addition, adding subwoofers to your car almost certainly means cutting holes in the trunk or rear compartment.

If you're adding a new stereo receiver, that means you'll need to remove the old one -- usually by removing the bolts or even using special tools -- then properly connecting the wires to the new unit. Again, there may be wire cutting and soldering involved here, too. Your dashboard might also need to be modified to accommodate the new stereo if it's a different size.

As a general rule, amps should be installed at least 3 feet (0.9 meters) from the receiver to prevent interference. The most popular method involves installing them under the seat or in the trunk. You'll need to wire the amplifier into the car's electrical system to power it, which can be complicated.

So what could go wrong if you install things incorrectly? A lot of things, actually. The speakers could be out of phase and sound distorted, you could cut the mounting point incorrectly and leave a gaping hole in your car door or you could wire it wrong and short out your electrical system. You run the risk of permanently damaging your car and your new stereo equipment if you do this wrong. In other words, unless you have the right tools, the right instructions, and the right experience, it may be worth the extra cost to have a professional install it.

Up next, how much stereo equipment do you really need?

We've discussed a number of options for your car entertainment system. But how much of it do you really need, and how much should you spend?

If all you want to do is get better car sound and you're happy with the features of your factory radio, in most cases, a good set of speakers is all you need. Speakers will dramatically increase your audio quality and you can get a great set without having to spend a ton of money.

A new receiver is a good way to go if your radio is outdated -- if you have a tape deck, for example, and want to hear CDs or hook up your MP3 player. Lots of stereos boast fancy graphics and equalizer settings, but if they don't do much more than your current unit, are they really worth the money?

If you're alone in your car most of the time, maybe a DVD receiver and a bunch of TV screens mounted overhead and in the headrests isn't necessary. But there are plenty of moms and dads out there who say having a DVD player to entertain the kids on long trips is a great investment.

In addition, think about what type of audio you prefer in your car. If you mostly enjoy listening to talk radio or classical music, a huge, bass-thumping subwoofer might not be for you.

It's possible (but not very likely) that a well-installed stereo and speakers could add to your car's resale value, but only if the equipment is installed cleanly and correctly. No one wants to buy a car full of someone else's shoddy work.

Of course, technically, you don't "need" any of this equipment. But whether you want to just get better sound out of your existing car radio, navigate trips a little easier, or turn your car into a concert on wheels, there is plenty of equipment out there to get the job done -- that is, if you've got the cash.

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