Car stereos are the brains of the entire mobile entertainment system. Components in your vehicle audio system control what you hear, how media is delivered, volume and tone, and more. In addition to controlling your media, many car stereos can also interact with your smartphone, enabling you to access your messages, calls, audio files, and even navigation.

Today's car stereos offer a ton of functionality. It's not that daunting if you think about what you want from a new car stereo.

Ask yourself why are you upgrading your receiver? Of course, there are a few reasons, music streaming capabilities, connectivity, touchscreen display, navigation, or maybe you're planning to build a full car audio system. Once you've identified your goals, you can narrow your options down to just a few.

1. Physical size, physical control

First, determine the right size for your console, physically measuring your console is almost foolproof. You may need to remove some trim pieces to see exactly what you're using, but you'll have to remove them anyway to replace the head unit.

Dimensions: single and double DIN
Before starting to choose a head unit, it is important to check the dashboard of the vehicle you will be using. Most head units fit into two size categories, called single DIN and double DIN, and most vehicles have single or double DIN dash sockets.

If the existing head unit is approximately 2 inches (50 mm) high, the replacement needs to conform to a single DIN standard. Single or double DIN  head units can be used if the existing unit is 4 inches (100 mm) high. However, installing a single DIN head unit into a double-DIN socket requires a spacer.

Also, consider controls on the receiver's face and software interface. The touchscreen is nice, but let's not underestimate the ease of use that good physical controls provide when you're driving at 70-plus miles per hour. Likewise, a confusing interface or a touchscreen that struggles to recognize your input can cause you to spend more time fiddling with the receiver when you should be looking at the road. I like a good physical volume knob over buttons for quick adjustments, but you may prefer a receiver that supports the steering wheel controls on your car via an adapter. Steering wheel compatibility varies wildly between the make and model of your car and the model of your chosen receiver, so you'll need to do a bit of research before you buy.

2. Audio sources

Answering this question is the next step in selecting the right car receiver, the most important bits that you should look for are the audio sources that you most often use. Knowing which options are "must-haves" will help you narrow your search and focus on the features that are important to you so that you can listen in your preferred ways：

Music from your phone: Look for a stereo that will control your phone or that has Bluetooth® streaming capability.
Thumb drives or music players: Most in-dash receivers feature USB inputs, so you can have a ready-to-go library of music in your car all of the time, loaded onto a thumb drive or other type of mass storage device. An auxiliary input lets you connect non-USB devices. Some receivers feature SD™ card slots, too.
CDs: If you still listen to discs, make sure your new stereo can play them. A CD or DVD receiver is what you need. If you don't need disc playback, then a digital media or multimedia receiver might be best for you. Read our digital media receiver buying guide for more info.
Pandora or Spotify: Many receivers let you control Pandora or Spotify when connected to your phone.
SiriusXM: If you want to add satellite radio to your new car stereo, make sure the stereo you choose is "satellite radio-ready." That means it can control an optional hideaway satellite radio tuner. If you already listen via the phone app or have portable satellite radio, then your new stereo just needs an auxiliary input or Bluetooth.
FM radio: Radios with a low FM sensitivity do a better job of pulling in radio signals. An FM sensitivity of 8 to 12 dBf is considered very good. Be sure to look for this detail in the stereo's description if a better-than-most AM/FM radio is high on your list.
HD Radio™ broadcasts: Radio stations broadcasting digital signals are becoming more and more prevalent. To gain the benefits of static-free reception and better sound quality, your stereo must have an HD Radio tuner.

3. App and Smartphone Integration

Nowadays, every customer looks for a unit that can be integrated with their smartphone and can function in tandem with it. So it is important to make sure that the aftermarket stereo that you purchase has that feature. One of the biggest things lately is smartphone integration with Apple CarPlay and Android auto. This simplifies driving a great deal and allows you to manage your smartphone via the head unit easily for a seamless and safer driving experience. OUSMIN is now focusing on Wireless Apple CarPlay and Wireless Android Mirroring to take things to the next level.

4. Local Satellite and Radio

Many people love to listen to the radio while they drive. Radio is also a great source for getting quick news bites and staying up to date with current affairs. Nowadays, traditional radios are being fast replaced by digital radios. Not only do these radios offer a crisper sound quality but they also provide some pretty useful functions like the ability to play songs directly from your Spotify digital library, so that you can enjoy the music that is tailored to your taste without having to shift your focus from driving.

5. GPS Navigation

A GPS allows you to focus on the road whenever you’re in a new area and you can navigate to your destination without having to stop at every street corner and asking a local for directions. Many aftermarket stereos come with integrated GPS systems but you don’t necessarily have to spend extra bucks for that. With the smartphone integration trend catching on, you can use GPS navigation on your car stereo via Apple CarPlay or Android Auto.

6. Power

While taking inputs from your audio sources is one function of the head unit; its other important function is to output the audio to your car’s speakers via its internal amplifier. This amplifier has two power ratings – peak power and RMS. Peak power is the maximum amount of power that your amplifier is capable of producing whereas RMS power is the amount of power that the amplifier will consistently produce with regular usage. Unless you’re someone who likes to blast their speaker at full volume all the time, you’d want to focus more on the RMS rating.

Generally, having high RMS power is good as it gives you more leeway in terms of volume without reaching the limit of the amplifier’s ability – which might lead to distortion. More wattage doesn’t always mean better audio quality though. It’s determined by many factors like the quality of your audio source, digital signal processing, digital-analog converter, equalization, and finally, your car’s speakers.


These parameters, however, aren’t set in stone. Most modern head units have audio tuning features, which give you the option to alter the texture and quality of output as per your needs. For example, the “Bass Boost” feature can be used to sharpen the lowest sound frequencies, “Band-equalizer” can be used to control the overall soundstage, and the “Time Alignment” feature can be used for course correction in case the music goes out of sync.

Furthermore, if you are looking to upgrade your car’s sound system by adding extra amplifiers, subwoofers, or other accessories, you should make sure that the car stereo you’re investing in has the option for upgradability. This can be determined by checking the number of preamp outputs on the rear end of the stereo. So make sure you have an adequate number of preamp outputs before you buy the stereo. Those preamp outputs also have a certain line voltage label (2V, 4V, and even 8V and 16V in some models) - the greater the line voltage, the lesser the noise in the output from your speaker. This is why you should consider a stereo with high voltage RCA pre-outs.

7. Budget

When upgrading a car audio system, it's important to be realistic. Anyone can build a killer sound system by throwing enough money at the problem, but not everyone has that option. That's why it's important to think about what you want, consider the other components you may need to buy, can then start working on finding the best stereo within your budget .and choose a head unit that fits your budget.