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Car Stereo Buyers Guide – Selecting a Head Unit

In the automotive aftermarket, one of the most upgraded items in any car is the stereo. Car owners of all ages often choose to upgrade their stereo first. The first step in upgrading the stereo is changing out the head unit or deck. The head unit is the control center for the entire stereo system and is the piece of the equipment the driver uses to control the system. There are many options and add-on accessories you can add to any head unit and it is good to consider which of these you may be interested in prior to purchasing the head unit.

Depending on your car, you may have a few options on the size of radio you choose. “DIN” is the terminology used to describe the physical size of the radio, a single din unit is 2×7 in size and a double-din is 4×7. Most cars come with one of three size factory radios a single “DIN”, a double “DIN” and a “DIN and a half.” Many late model cars come with a double din sized stereo or the ability to add one. Some cars come equipped with a “DIN and a half” radio or even a single “DIN”, but have the ability to add a double din unit without major modifications, other cars do not. If you take a tape measure and measure the face of your factory radio you can determine what size radio you are going to need. Doing some research online can also help you determine if you are able to install a double din radio in your car.

Once you have decided what size head unit you would like to purchase, you will have to make choices on a wide variety of other options. Some of these include:

Video Features

One of the first decisions to make when purchasing a head unit is to decide whether you want a head unit that will play video or not. This decision will help narrow down your choice for a head unit. If you do decide to purchase a head unit that will play video, there are three varieties you can choose from: the flip-out single din, the double din, or the single din with a tv built in. The flip out style features a 6.5″ or 7″ tv with either touch screen controls or buttons on the side or bottom. The radio will motor out from the dash and then flip up for the driver to see the screen. A double din also features a 6.5″ or 7″ screen, touchscreen controls, or a row of buttons either on the side or bottom or a mixture of the two, having a touch screen plus other buttons on the bottom or side, but is flush in the dash board. A single din with a built in tv is a standard size din radio, typically with a 2.5″-4″ tv built into the face.


If you have selected to use a head unit that will play video, you may have the option of adding on-screen navigation to that head unit. You may also have the option of purchasing a video deck that also has built-in navigation. Installing navigation generally requires a disk or hard drive and an antenna you must mount on the outside of the car to track your position. If you plan on adding navigation, it is generally more expensive to add a video head unit that will allow on-screen navigation than to purchase a hand-held navigation. However, the looks and ease of use with having it built in to your radio is well worth the extra cost.

RCA Pre-Outs

A RCA pre-out is a jack on the back of a head unit that allows you to connect signal cables or RCA cables to, to transfer the sound from the head unit to the amplifier. The number of RCA pre-outs your new radio will have is an important feature to look for. Many high end radios will have 3 pre-outs: one for a front stage amplifier, one for rear stage amplifier and one specified for a subwoofer amplifier. If you plan on building an extensive stereo and using a 4 channel amplifier for your mid-range and high sound, 3 pre-outs is the only way to go. It will allow more adjustability and make tuning the amplifiers a breeze.

Subwoofer level control

Having the ability to adjust the level of the subwoofer amplifier through the radio is a feature many desire. This allows you to slightly change the gain of the amp through the radio, preventing you from having to get in the trunk or where your amplifier is located to adjust it. If you desire this feature, select a radio that has a subwoofer level control, which can be signified by a separate RCA pre-out labeled subwoofer, or SW.

Wattage of Radio

The wattage of the radio is the amount of power the head unit supplies to the speakers. Most radios will be labeled “45×4” or “50×4”; this simply means 45 watts for each of 4 speakers, or channels. What you have to understand is the 45 or 50 watts is what is supplied to your speakers at peak moments in a given song, not throughout the entire song. The rating that is more important is the RMS rating. RMS simply refers to the nominal power, which is the amount of power your speakers are supplied with at all times, which on most head units is between 15-18 watts.

Ipod/MP3 Player

In today’s music world, everything revolves around one thing: the Ipod or MP3 player. Many consumers in the market for a new radio are simply looking for one that will allow you to play an Ipod or MP3 player through, as they may not have the option of adding it to their OEM radio. There are a couple different ways this is accomplished on an aftermarket radio. You can purchase a radio with a dedicated Ipod connection on the back or one with an auxiliary headphone jack on the front or the rear. The advantage of the direct connection is that it allows you to pull up your playlists, songs, and artists through the radio; it does not require you to have the Ipod or MP3 player in your hand to select a song. The other option is the auxiliary jack, which can be cheaper to connect. All that is needed is a headphone-to-headphone cable, but it requires you to select songs on your Ipod, adding another step and another distraction to a driver. A direct connection to your radio is the only way to go. The add on wireless modulators you might see in the store offer terrible sound quality and will annoy you with their problems rather quickly. These can range from interference issues, to bad sound quality, to possibly no sound at all. They use a wireless signal to transfer sound to your radio and in the process will pick up the noise from any and all electronic devices in your car. You may be required to purchase an add-on module or cable to allow you to connect your Ipod or MP3 player.


Another option for listening to your MP3’s or portable music on your car stereo is a USB connection. Some radios will have a plug on the back while some will have a jack on the front of the radio. You can load a lot of music on a small zip drive and then just plug it in and go.


As more and more states require a hands-free kit to talk on your cell phone while you drive, this may be something you can’t skimp on. It is far easier, and usually cheaper, to select a head unit that will allow you to run all your accessories through. In this case, you purchase an add-on bluetooth interface and the radio itself will act as the hand-free kit and automatically interrupt music when your phone rings. You will need to mount an antenna in the car’s interior which will pick up your voice during a phone call, and you will hear the person you are talking to through your car stereo.

CD Changer

If you use a CD changer or plan to, you may be able to directly connect it to your radio and select your songs on the changer through your radio. This prevents you from having to have a separate lcd screen and controller to choose your songs. Purchasing a separate CD changer would be required.

HD Radio

An HD tuner allows your radio to pick up high definition versions of local radio channels. The programming is generally the same, you just get a higher quality signal. A separate tuner is required to pick up these stations.

Sirius/XM, Satellite Radio

Many drivers today use satellite radio as their primary source of listening pleasure. These subscription services feature commercial free music channels and censor free talk radio.

These services offer up to 200 channels and have very good programming. Truck drivers and folks who travel a lot especially like satellite radios as it allows them to pick up the same radio stations no matter where they are. A radio that is set up for satellite radio allows you to play the music directly through the radio and control all your options through the radio. This prevents you from having a separate tuner for your satellite radio and makes using it that much easier. An add-on tuner and a paid subscription are required to tune in to these channels.

Once you have decided on the features you are looking for in your radio, happy shopping. Many of the name brands in car audio, including Alpine, Kenwood, Pioneer, JVC, Sony, Jensen and many others will offer head units that offer some or possibly all of these features. Picking the proper head unit that will allow for the easiest integrations of your current or future accessories, including Ipod, satellite radio, bluetooth, etc., is essential. By making the right choice first, you can set it up where you can control all of this through the radio and not have a separate Ipod adapter, satellite radio tuner, etc. This will allow you to have a much more streamlined system and allow for a good, clean finished look in your car.

Source by Jason Helferich

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