How to Build a Car Stereo System and Install It

A Hi-Fi music system with speakers and subwoofers installed in the trunk of a hatchback vehicle
Just like a home stereo system, speakers are the most important part of car audio. Maica / Getty Images

Building a car stereo system can be a challenging project. Unlike a home stereo system, where one can practically mix and match equipment as desired, car speakers and components are often designed with a specific type/make/manufacturer in mind. Plus, it's difficult to install and connect everything together in the tight confines of a vehicle.

You can choose to purchase and install everything at once. Or you can start with a new car stereo system and replace other components in stages over time. Either way, make sure you focus on selecting excellent speakers, which is the most important part of a good system.

Car Stereo Speakers

Like home audio, speakers are the most important part of a car audio system. Speaker type, size, shape, mounting location, and power requirements are critical considerations for a car audio system.

The first step should be to figure out which kinds of speakers will fit in your car. If you're interested in a complete system, consider front, center, and rear speakers as well. Keep in mind that some speakers may require a special enclosure, which tends to take up more space.

Next, cross-check the power handling capacity of the speakers with the power output of the amplifier(s) or head unit. Make sure to include car audio crossovers for mid-range speakers and tweeters as well. You don't want to under-power the equipment.

Car Stereo Subwoofers

Subwoofers designed for vehicles require more power than typical speakers. They also need to be mounted inside of an enclosure when installed in a car. Enclosures can be custom-made as a DIY project (if so desired), or you can just buy one specifically designed for the make/model of your car.

There are many types of subwoofer enclosures to consider, based on the size of the woofer as well as the type of vehicle. The most common sizes for a mobile subwoofer are 8", 10", and 12". Some manufacturers offer amplified subwoofers with the enclosures; these are easily installed in the trunk of vehicles or behind the seats of pick-up trucks.

Car Stereo Amplifiers

Most car head units have built-in amplifiers that typically run about 50-watts per channel. However, an external amp may be the best choice, given that they offer more power as well as the ability to separately adjust the bass, mid-range, and high frequency levels separately. Balanced systems sound better overall.

Subwoofers require more power than standard speakers (mids and tweeters). You could consider a separate amplifier for the subwoofer and let the amplifier built into the head unit drive the speakers. Keep in mind that using separate car amplifiers requires crossovers between the amplifiers and speakers in order to correctly distribute signals.

Car Stereo Head Units and Receivers

When building a system, you can use your existing in-dash head unit (or receiver) or replace it with a new component. However, the downside is that most factory head units don't have pre-amp outputs, making it so you can't use external amps. There are speaker level to line level converters, but these tend to sacrifice some sound quality.

If you are replacing the in-dash head unit, the chassis size is important to know. There are standard and oversized head units available. A standard size is known as single DIN, oversized units are known a 1.5 DIN or double DIN. Also, consider if you want a CD or DVD player, with or without a video screen.

Car Stereo Installation

Installing a new car stereo system can be tricky, but if you have the tools, a good knowledge of electronics, basic understanding of cars, and patience, go for it! There are many online guides that provide instruction and tips for car stereo installation.

If not, have the system installed by a professional; there are many companies that provide comprehensive installation services. Be sure to consult your car dealer and ask if the installation will affect the vehicle's factory and/or extended warranty.

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