Don't call it your "radio" because it is much more than that, it is the head unit of your car's stereo system. It is the central command for your entire vehicle's audio system and it is what lets you do everything from changing the radio station to adjusting the balance of the output.

Head units have gotten more and more complex over time and today you can find one that features a touchscreen display and that allows you access your smartphone, car mirrors, and more.

Selecting the Head Unit

So, how does one go about choosing the right head unit? You simply ask yourself what you want from this device. If you are a very simple sort of person and want only the basics in your car's audio system, you can opt for a tuner (which is the actual "radio") and little else. The head unit is going to allow you to choose which sort of "source" you are hearing or using (including the "antenna" that receives the radio signals in the air), and this is often what helps you to see how complex a head unit can be.

For instance, there are usually options for different sources that might include the CD player, the radio, a shortwave radio, and various other sources of input. 

Consider you might subscribe to one of the satellite radio options, and that would mean you need a head unit capable of interacting with that sort of broadcast too. 

We just mentioned that you can also elect to have CD as a source for music, and if your head unit features a CD player, you can easily listen to the tracks of your choice. Do keep in mind that operating a stereo while driving can be hazardous, and this is why many of the top units come with a remote control device too. This can allow you to change tracks or even to change discs with the tap of a single button.

Connectivity

The best head units also have ports and plugs for alternative sources such as MP3 players, iPods or iPads, headphones, and even USB or other computer friendly ports. There are also Bluetooth options on most head units as well. Should you desire the widest range of listening options, it means finding a head unit that can effectively manage this array of devices and sources.

Amplifier

You also want to consider the amplifier. This is a key issue in terms of the quality of the output. An "amp" is what takes the signals from things like the radio, CD, or alternative sound source and boosts its power before sending it to the secondary part of the amplifier. This is then sent to the speakers. So, if you have a low power amp, you need low power speakers, and will not get the optimal sound from the system. The head unit may be able to help with specific adjustments to the sound, but it cannot improve things to dramatically.

Controls

This leads to the different controls that the best head units offer. For example, most have equalizers that allow you to adjust the treble, bass, and other parts of the audible signal. There are some head units with more advanced controls, and some have special "presets" that you can use for specific types of sound such as live singing, rock, classic, etc.

Pricing and Choosing

Ultimately, the head unit is what gives the listener control over the quality of the sound being played through the car's audio system. It may not have a huge impact on the sound when the power in the system is low, but it is the one thing that can allow the listener to fine tune the output to get the best results.

Thus, if you spend a lot of time in the car or you want optimal listening experiences when using the vehicle, it is best to invest in the finest head unit you can afford. Like so many electronic devices, head units can vary widely in cost. The most popular brands include Pioneer, JVC, Sony, Kenwood, Alpine, and Fusion.

It is a good idea to ask yourself what you want from the system in order to choose the best unit. For example, if you are going to listen to satellite radio and high-quality audio files, find a head unit that has built in receivers for the satellite signal and the fine tuning adjustments that can make your listening experiences truly optimal.