Car audio amplifiers: Everything you need to know

Car audio amplifiers: Everything you need to know

on December 08, 2023

One of the most important components in an efficient vehicle entertainment system are audio amplifiers. The quality of the final sound largely depends on this device. These devices, from their most rudimentary form, have been used for about 100 years by people with the aim of significantly increasing the capacity of audio signals. Thanks to technology, they are now more innovative and powerful. 

While the concept of increasing the power of an audio signal is simple, it can be somewhat complex to execute the process accurately and efficiently. Its design and operation is both a science and an art form, so it is important to know it thoroughly.

It is necessary that you be able to familiarize yourself with this component and understand everything related to it.In this article, we will look at everything you need to know about audio amplifiers.

What they are, what role they play in the car, their different types and what you should take into account when buying one. 

What is an amplifier?

Broadly speaking, an amplifier is a device made up of electronic circuits that increase or amplify audio signals. Additionally, they are capable of providing the required power for the speakers. Audio amplifiers enhance your car's overall stereo system by offering the following benefits:

  • Improve sound quality. An external amplifier provides an impeccable power source for your speakers without strain or distortion. The improved design allows for clean, clear sound at all volume levels. 
  • Increase performance in speakers. Speakers and component systems tend to need more power for maximum performance than you can get from your regular car amplifier and head unit. 
  • Provide more power to the subwoofers. A subwoofer requires much more power to operate. So if you plan to upgrade the stereo system, you will need an external amplifier to provide better performance. 

Now, at the basic level, there are only two types of power amplifiers:

  • Analog 
  • Switching

  • Both basic types are divided into more than a dozen classes identified by letters. 

    Some of these classes, such as T and Z, are proprietary and trademarked designs, and others, such as A and B, are produced by a variety of manufacturers. 

    • Class A: Clean output, high fidelity, low distortion. Generates a lot of heat. 
    • Class B: Efficient, has a smaller size, generates less heat. Lower audio fidelity and possible signal distortion. 
    • Class A/B: More efficient than class A; less distortion than class B. Less efficient than class B and more distortion than class A. 
    • Class D: Extremely efficient. Distortion at high frequencies.


    What role does an amplifier play in the sound of a car? 

    Car audio amplifiers


    Amplifiers boost a very small electrical audio signal from the head unit to a higher voltage. It can drive wired speakers with more power, volume and sound clarity.

    Most car audio stereos only have about 15 to 18 watts available and start to distort a lot at their maximum output. An external amplifier not only solves this problem, but can also greatly improve the playback fidelity of the music you enjoy every day. 

    For powerful bass, subwoofers need a lot of power that is impossible to get with just a car stereo. This is also a problem when you want to use 4 or 2 ohm speakers, as they need more power to get maximum performance when upgrading your sound system.

    An external amplifier provides higher sound quality as it can deliver less noise and distortion due to the more advanced electronics included for that purpose. Car stereos often use a more basic design and cheaper components that limit what you can hear. 

    Types of car amplifier 

    Types of car amplifier

    A differentiating factor between amplifiers is the number of channels available. They have multiple configurations, each best suited for different speakers. 

    Single channel amplifier 

    This type of amplifier is designed for low-frequency reproduction and features built-in bass boost and low-pass filters.The best option would be a class D mono amplifier, because they produce less heat, draw less current, and are more efficient than conventional amplifier designs.

    2 channel amplifier 

    Used for full range speaker systems. You must have high pass filters. They are mainly used to connect the door speakers. 

    A two-channel amplifier can power: 

    3 channel amplifier 

    This amplifier is perfect for powering a pair of speakers and a subwoofer. This setup is ideal for your front or rear speakers with an external amplifier. 

    4 channel amplifier 

    It's ideal when you want to control the front and rear sound, allowing the power to go to all four speakers individually. Additionally, it can be bridged to power the stereo speakers with a subwoofer, using two of the four channels for the subwoofer. 

    A four channel amplifier works to power: 

    • Four speakers. 
    • Two speakers and a subwoofer: You can use a four-channel amplifier to power a subwoofer and two full-range rear speakers by connecting two of the channels to power the subwoofer. 

    If you want to add a subwoofer, you can also use a four-channel amplifier to power the four coaxial speakers and a single-channel amplifier to power the subwoofer.

    5+ channel amplifiers 

          One amplifier with five channels can power the entire car audio system: 

    • Two speakers in the front. 
    • Two speakers in the rear. 
    • A subwoofer. 

    Finally, amplifiers with 6 to 8 channels are designed to power active 3- and 4-way systems, with one amplifier channel dedicated to each driver. For example, tweeters and midrange speakers and two channels joined together to power a subwoofer. 

    How to choose the best amplifier for my car? 

    Audio amplifiers that are powerful enough and match your other components will make a big difference in sound quality. You should keep in mind that the type of amplifier you choose will depend on a number of factors, such as the speakers, whether you are using a subwoofer, and where you plan to install the amplifier. 

    Below we explain these factors that you should take into account: 


    When purchasing an amplifier, you will need to find one that is compatible with the other audio system components you already have. 

    Impedance for subwoofer amplifier 

    Make sure the power of the amplifier matches the power requirements of the subwoofer, which is known as impedance and is represented in ohms. For example, a 2 ohm subwoofer needs an amplifier that is stable down to 2 ohms or less.

    From the main unit 

    If you're building an audio system with external components, use a head unit with preamp outputs and an amplifier with line-level inputs. This setup will send a signal to the amplifier and create the best, clearest sound possible. But, if you're using an existing head unit that doesn't have preamp outputs, you'll need to use an amplifier with speaker-level inputs to improve the sound. 

    How many channels do you need? 

    You'll also need to match the number of channels in your amplifier to the number of speakers you have, as well as match the power output of the amplifier to the power handling of the speakers. The number of channels you require in the amplifier depends on the number of speakers you have in the sound system. Generally, you need one channel per speaker. 

    Power requirements 

    Whether you're upgrading your speakers or using existing ones, make sure your amplifier's power matches them. Find the continuous RMS (root mean square) power rating on the speakers. The RMS is usually a range value, for example 5-60 watts RMS. Take the top number of the RMS rating and find an amplifier that can output 75-150% of that number. To find 75%, multiply it by 0.75 and to find 150%, multiply it by 1.5. For example, a speaker with a power handling of 200 watts needs an amplifier with a power rating between 150 and 300 watts.


    When purchasing an amplifier, you should also think about the installation location and how you will route the cables. First, you must find a convenient space in your vehicle to place it and then you can buy it to fit that space. Therefore, choose an amplifier location in your car and measure the space to know what size to look for (the same goes for installing speakers and subwoofers). 

    These are common installation locations for audio amplifiers in vehicles: 

    • Against the passenger side firewall. 
    • Under the seats. 
    • In the trunk. 

    Currently, there are various stores where you can obtain these components. At Genius Audio we offer you a wide range of high quality and performance equipment to improve the performance of your vehicle. 

    We have class AB D and full range monoblock or full range audio amplifiers of different sizes and with various specifications and designs. Our products have the highest quality standards and we can also provide you with continuous technical service.


    Nowadays, amplifiers can power an entire car audio system with excellent sound quality and volume. Some are very compact and can be installed under a seat or even inside the dashboard. A good amplifier provides several times the output power of an average car stereo. In addition, they have a much clearer and crisper sound.

    Audio amplifiers have various benefits in addition to being a necessity in some cases. Conventional stereos, even today, can only produce 15 to 18 watts of power per channel at most. At higher volumes and when trying to drive speakers that need more power, the sound of a stereo becomes distorted and terrible. 

    Therefore, if you want to enjoy better sound, you should include an audio system with amplifiers. And, now that you know the basics of choosing the best ones, contact the experts. At Genius Audio we have various models of amplifiers so you can choose the one that best suits your needs. 

    Do not hesitate to contact us.


    If you liked this article, you might be interested:

     How does an audio DSP work?

    How to connect a car stereo to a power source?

    What does LPF mean on an amplifier?



    Please note, comments must be approved before they are published