The Main Components of Your Car Audio System

For as long as people have been driving, they’ve wanted to listen to music. And while it used to be impossible, today’s factory systems are well set up from the start.

Car Audio

From a basic radio to premium receivers with touchscreens, there’s a lot of choice. Upgrading your car’s audio doesn’t have to be expensive, either.

The head unit is the center of your car’s audio system. It receives audio signals over the air (radio) or from CDs and other recorded media. It then sends those signals to the amplifier, which increases their strength and turns them into electrical impulses that drive your speakers, generating sound waves. Those impulses give your ears the illusion that individual instruments are playing in different locations around your vehicle, which helps to create an overall more realistic musical experience.

Your head unit will also include inputs and outputs for the various components that make up your system. For example, you can connect auxiliary and USB devices for playback of music files or streaming of radio and phone calls. Some head units even have HDMI inputs to support in-vehicle entertainment systems such as dashcams and GPS navigation.

If you’re going to use an aftermarket amplifier for the front and rear speakers, your head unit will likely have a pair of preamp outputs. These connect to the amps that will drive your speaker wires, and if you’re using an aftermarket subwoofer, they will also power it.

A 3.5-mm auxiliary input jack allows you to plug in devices like iPods and smartphones, and most head units offer a Bluetooth feature for hands-free calling and streaming audio. Some head units have a microphone input for voice commands like Google Assistant, though you’ll need to purchase a separate adapter for your vehicle.

Most head units fit into double-DIN (7-by-2-inch) dashboard openings. Pioneer’s AVH-3500NEX is our top pick, with a clever slide-out touchscreen for Apple CarPlay and Android Auto. This double-DIN stereo has options for a wired or wireless connection to your smartphone, HD radio, and FLAC support. It can also display engine performance data on its 6.9-inch screen.


The amplifier is the second major component of any car audio system. Its purpose is to increase the power of the signal sent from the head unit to the speakers and create sound. Without a good amplifier, the audio signal is too weak to move the speakers and make music.

If you’re looking for more powerful signals than your head unit’s in-built amplifier can deliver, then you will need an external one. The amplifier can also allow you to connect additional speakers, making it a key component for building a great in-car stereo system.

When shopping for an amp, avoid focusing on the “peak” or “rated power” ratings and instead look at the RMS (rate of constant power). This is the most important rating because it reflects the amplifier’s ability to consistently push out high levels of music without causing distortion.

A good-quality amplifier can give your favorite tunes new life by bringing out musical details and improving clarity. This results in better music at all volume levels, so you can enjoy the music as loud as you like or keep it at a more civilized level.

There are a variety of amplifiers available on the market, from mono to multi-channel. The number of channels correlates to the amount of power that can be distributed across the speaker system. A popular option is the 4-channel amplifier, which can either be connected to a set of front and rear speakers or bridged to a subwoofer.

A good amplifier can help you hear your music at a more natural volume. Test your system by listening at low, medium, and high levels. A good system should produce a consistent balance of bass, mids, and highs across the entire range of volume levels and be free of distortion at any level.


When you want to crank up the volume and really enjoy your favorite songs, the speakers are the component that will make or break the sound quality. A good set of car audio speakers will offer clear, crisp, and vibrant music. They will also allow you to hear aspects of your favorite songs that were previously missed when listening through the factory speakers.

The first step in selecting the best speaker for your vehicle is to figure out where the weakest point of the existing system lies. Is it not loud enough, or does the bass response lack solid depth? Figuring out where the problem is will help formulate a plan for fixing it.

Next, you will need to decide what size speakers to purchase for your car or truck. There are a number of different sizes to choose from, ranging from the very small 5×7” to the large 6×9”. The smaller 6.5″ speakers are very popular with consumers because they can easily fit into the factory mounting holes in your vehicle’s door panel.

The other important specification to consider when choosing speakers is their impedance rating, measured in Ohms. This is a measure of how much power the speaker can accept from an amplifier. Speakers with higher impedance ratings will need more power from an amplifier to reach the same volume as those with lower impedance ratings.

Another factor to consider is whether you are going with a component or coaxial-style speaker setup. Component car speakers consist of a separate woofer and tweeter, which allow the music signal to be split and sent to the correct driver, improving the overall clarity of your audio experience. Most component speaker sets include an external passive crossover, which is a compact circuit that includes capacitors and inductors to divide the audio signal into different frequency bands and direct the appropriate frequencies to the woofer or tweeter.


A subwoofer is the component in your audio system that produces those low-bass sounds. Without one, your car stereo may still sound great, but the beats won’t really slap, knock, or pound; the low sounds are missing. A subwoofer can amplify those undertones, giving your music the heartbeat it needs to feel more textured and lifelike.

The frequency range of a sub determines how deep a note it can play, but the type of enclosure in which it is mounted will have a major impact on its performance as well. A sealed box will produce the most accurate bass, while a ported enclosure will generate more volume from the same subwoofer.

Choosing the right subwoofer size depends on how much room you have available in your vehicle and what kind of bass you prefer. A larger subwoofer will produce deeper bass, but it is also more expensive and requires a large enclosure to work properly.

To measure the size of your subwoofer, you’ll need a measuring tape and a pencil. Begin by measuring the outside edge of the speaker frame, including any grilles or caps. Make sure to measure the depth of the speaker as well.

Once you’ve measured the size of your space, it’s time to start shopping for a subwoofer and enclosure. It’s important to buy a subwoofer and enclosure that match in power rating so they can play at the same volume level. You should also purchase a subwoofer mount kit to ensure the woofer is mounted securely in your vehicle. A quality subwoofer mount includes a metal brace that supports the woofer, a rubber seal to prevent rattling and noise, and a plastic crimp ring connector for connecting your remote wire.


Bluetooth allows you to wirelessly connect your phone to your car’s audio system for hands-free calling and music streaming. The most cost-effective way to add Bluetooth is with a universal kit that mounts to your dashboard and is typically easy to install. These kits typically use FM transmitters, which are prone to interference from radio stations and other sources of radio waves on the same frequency.

A factory Bluetooth adapter is a great option for newer vehicles and offers the benefit of being engineered for your specific make and model vehicle. The factory adapter will offer the best audio quality and may come with detailed installation instructions. If you’re looking for a more luxurious upgrade, consider a double-din touchscreen head unit that comes with Apple CarPlay and Android Auto integration.

The latest Bluetooth models offer an additional feature that allows you to mirror your smartphone screen on the car’s display. This makes it easier to operate your smartphone while driving by allowing you to see apps, music, and digital maps. This is a feature that many modern car manufacturers are offering as standard equipment in their vehicles.

If you are experiencing Bluetooth issues, it may be helpful to try restarting your phone and stereo. Also, ensure that your phone and stereo are updated to the latest versions of their respective operating systems.

If your mobile device has a passkey, you may be required to enter the code in order to establish a connection. The Bluetooth stereo system and your phone will remember this pairing information, allowing you to easily connect in the future. This step is usually optional in most cases but can be useful when troubleshooting Bluetooth problems.