Everything to Know About Car Audio Systems

The Differences Between Stereo, Head Unit, Receiver and Tuner

touchscreen head unit receiver
Tuners, receivers, and controllers are all types of head units, but each one is slightly different from all the others. Photo courtesy of James Cridland, via Flickr (Creative Commons 2.0)

Question: What’s the difference between a car stereo, head unit, receiver, etc, etc? 

I have the money to upgrade my car audio system for the first time, so I’ve been doing some research before I dive in. One thing I’m not clear on is the difference between a car stereo, a head unit, receiver, tuner, and all the other names that get thrown around, or is there even a difference in the first place? Basically, I’ve heard some conflicting info, and I don’t want to buy a car stereo and then find out later on that I would have been better off with, say, a receiver or whatever.

Answer: A lot of jargon gets thrown around when it comes to car audio, and some of it can get pretty complicated. Fortunately, this is one area where it’s actually pretty easy to nail everything down. Some of the terms you listed are synonyms (car stereo and head unit), and some are actually different products (receiver and tuner).

Here’s a basic rundown of some of the most common names for a head unit, and what they actually are:

  • Car stereo is a catch all term for both head units and car audio systems as a whole.
  • Head unit is another catch all term that can refer to any in-dash car stereo
  • Receiver is a head unit that features a built-in amplifier.
  • Tuner is a head unit that doesn’t have a built-in amplifier.
  • Car radio is a catch all term that refers to receivers and tuners.
  • Controller is a head unit that doesn’t include a radio tuner.
  • Mechless is a solid state head unit that lacks a CD, DVD, or cassette player.

    Car Stereos and Head Units

    Starting at the top of the heap, the term “car stereo” can refer to a huge range of devices and systems. This term can refer to an entire car audio system (including the head unit, amp, equalizer, crossovers, speakers, and everything else), but it is also a synonym for head unit.

    The term “head unit” can also refer to a lot of different types of devices, but they are all in-dash stereos. The head unit is essentially the brain or heart of a car audio system, and it can include a radio tuner, CD player, auxiliary inputs, and even built-in components like amplifiers and equalizers. From this point on, terms become more specialized.

    Receivers, Tuners, and Car Radios

    Two closely related types of head units are referred to as receivers and tuners. Both of these types of head units include a built-in radio tuner (typically AM/FM), which is the only feature they both have to include. For that reason, they are also referred to as car radios. A lot of receivers and tuners also include features like CD players, auxiliary inputs, Bluetooth connectivity and USB ports, but that can vary from one model to another.

    The feature that differentiates a receiver from a tuner is a built-in amplifier. Where receivers include built-in amps, tuners do not. Most OEM head units are receivers simply because it’s more expensive to build a car audio system with both a tuner and an external amplifier, although there are some exceptions. The majority of aftermarket head units are also receivers, although tuners are also available for people who are interested in adding an external amp and getting the best sound quality possible.

    Of course, it’s also worth noting that some receivers include preamp outputs. That basically just means that although the head unit has a built-in amp, which makes it a receiver, it also has audio outputs that bypass the amp. These head units are great for anyone who is building their system piece by piece, since you can rely on the built-in amp until you get around to installing an external one.


    Head units that don’t fit into the larger “car radio” category are referred to as controllers because they don’t receive radio signals because they don’t have radio tuners. These head units may or may not have built-in amplifiers, and they can include a whole range of different features and options, including:

    Choosing the Right Head Unit

    If you’re concerned about choosing the right head unit, then these terms can be extremely helpful in the decision making process. For instance, you might want to buy a receiver that includes built-in preamp outputs if you’re building your car audio system piece by piece. This will allow you to keep your options open, since you’ll be able to add an external amplifier at a later date if you decide that you want one.

    Conversely, you’ll probably want to buy a tuner if you’re building your whole system at once, and you’re including one or more external amplifiers, and you might even prefer a controller if you never listen to the radio.

    In any case, it’s important to remember that these terms aren’t always used properly, which can get confusing. The important thing is to understand the definitions yourself, so that you can apply that knowledge when doing your own research and putting your system together.

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