how to choose an amplifier for car speakers

How to Choose an Amplifier for Car Speakers for First-Timers

Amplifiers change the music game in any setting, including cars. Many people buy amplifiers for their car speakers to improve the sound quality. Choosing an amplifier may be challenging, but no worries. We will guide you on how to choose an amplifier.

Factors to Consider When Choosing An Amplifier

When choosing an amplifier, there are some factors you must consider. These determine the quality of the product you get and if it is worth the cost. Knowing the options available will guide you to an amplifier that best suits your needs. We will examine some of those factors now.

Number of Channels

The first thing you need to consider when choosing an amplifier is the number of channels. There are many things to think about when deciding on the number of channels for an amplifier.

For some people, it is all about the sound system’s class rating and quality. A non-specialist is content with the same number of channels as car speakers. In that case, that would be a channel per speaker.

This means that if you have two speakers in your car, you should get a two-channel amp. Each channel will serve a separate speaker, especially if they receive different signals. Amplifiers with 1-4 channels are more common than those with 5-8 channels.

If your car’s audio system has a subwoofer, you should consider it when choosing an amplifier. For example, a car with two speakers (front and rear speakers) and a subwoofer will need three channels. Once you know how this works, you get closer to making the right decision for your car’s audio system.

Power Ratings

Power is another thing you should consider when choosing an amplifier. Amplifiers work to increase the sound from your car speakers. The more power an amplifier has, the louder it can get.

Power depends on the watts per channel. Choosing an amplifier with as much power as your speaker or more is advisable. This precaution is to prevent under-powering your car’s speakers.

The power rating of an amplifier depends on both RMS and peak power. To make the right decision about power, you must focus on the RMS rather than the peak power. When you are about to buy an amplifier, check the specification for both power ratings. Manufacturers often deceive buyers with the peak power rating when advertising.

Peak Power

The difference between RMS and peak power is in the time frame. Peak power is the maximum power a speaker can produce within a short period without damage. If it maintains the peak power for longer, the speaker will become damaged. This measurement is not a true test of an amplifier’s power.

Root Mean Square (RMS)

Car audio & speakers

Instead of the peak power, you should pay greater attention to the RMS (root mean square). The root means square stipulates how much power a speaker can handle over a long time frame. The RMS is also referred to as the speaker’s continuous power rating.

There is more to know about the power ratings of amplifiers and the efficiency of the audio system. As a beginner, you will get by knowing to give more emphasis to the RMS over the peak power.


Impedance is like power, but the two have some key differences. First, impedance depicts the resistance a speaker provides to an amplifier’s current. The impedance of a speaker is how much current can pass through the speaker at a particular voltage. Hence, lower impedance means a speaker can handle higher power.

One thing to remember is your speaker must not be overpowered or underpowered. Either situation will result in disaster. Either the speaker’s sound ends up below quality, or the entire system blows up.

System Compatibility

Another factor you should consider before choosing an amplifier is its compatibility with your car’s audio system. The type of amplifier must be compatible with the speakers and other audio components of the sound system.

Building your car’s audio system from scratch gives you more freedom to decide on the component systems,

If you are buying an amplifier for a factory head unit, you need to consider the speakers’ specifications. The main feature to look out for is “speaker-level inputs” to ensure improved sound quality.

Cars with coaxial speakers are less challenging since all the component speakers are together. While nothing beats building your preferred audio system, speaker-level input comes close.

Amplifier’s Features/Specifications

Powerful car music amplifiers in car trunk.

When buying an amplifier, you need to check the specifications. You need the amplifier’s specifications to be compatible with the speaker’s. Here are some features you should check when buying an amplifier for midrange speakers.

Audio Filter

Audio filters are essential to the performance of your amplifier. They control the frequencies sent to the speakers, allowing you to fine-tune the amplifier. Amplifiers’ audio filters are categorized into fixed and variable filters.

Fixed filters have one setting type, as programmed by the manufacturer. Meanwhile, variable filters allow you some measure of freedom. For example, you can change the setting to determine which filters affect frequencies.

There are different types of audio filters in amplifiers. They include a high pass filter, which allows frequencies higher than a specified frequency to pass through. There is also the low pass filter, which is the opposite of the high pass filter.

With the low pass filter, all signals below the specified frequency are allowed. But audio signals above the limit are muted. The final type of filter is the subsonic filter. This filter mutes low frequencies that are not within the audible range.

These frequencies are usually impossible to hear. The filter protects your amplifier and speaker from having to reproduce them.

Adjustable Input and Output Levels

Another feature to look out for is adjustable input and output levels. An adjustable input level allows you to boost or end the signal sent to your amplifier from the stereo. This feature helps minimize distortion as you can determine the input signal strength sent to your amplifier.

An adjustable output level allows you to control the signal strength the amplifier sends to the speakers. This protects the stereo amplifiers from distorting and ensures that your speakers are not overdriven. This feature is less about the volume level but ensures a wide range of amplifier power.


You need an amplifier with high resolution. This will complement the huge frequency response of high-quality speakers. Due to this reason, standard types of amplifiers cannot reproduce all the audio.

Some tones cannot be heard distinctly. Combining an amplifier with the original recording will improve audio quality. Usually, what you get with high-resolution amplifiers is greater depth and ambiance.

Speaker Level Inputs

An amplifier works in conjunction with your car’s speakers, and the ability to control the speaker level input helps with that. An amplifier with speaker-level inputs enables you to send signals to the amplifier from your car stereo. You will appreciate this feature if you do not have line-level outputs on your car’s receiver.

Digital Signal Processing (DSP)

DSP allows you to tune your car’s amplifier by adjusting the Signal Delay, Phase, and EQ. Doing this will bring the best sound quality to your car’s audio system. If you want, you can opt for an onboard DSP amplifier. It is not one of the first features people consider but can help you decide between two almost equal options.

Benefits of Amplifiers for Car Speakers

What is the big deal about amplifiers for car speakers? It is simple. Many people install amplifiers in their cars to complement their car’s audio system. These are some benefits of amplifiers for a pair of speakers.

Improved Sound Quality

While not the most important factor, many car owners consider the sound system when buying a car. You may not know that your car’s speakers are insufficient.

Amplifiers change the game as they allow speakers to emit sounds without straining their capacities. As a result, amplifiers enable you to hear clean and defined sounds from your car’s stereo.

Upgraded Speakers

When upgrading from your current speakers, you need a good amplifier to power it. Settling for an in-dash receiver will not be enough for a larger speaker to reach its full performance capacity. Thus, getting aftermarket speakers means that you have to buy an amplifier to improve the power source.

Improved Power for Subwoofers

If you are using a subwoofer, you need to get an amplifier to work with it. This is because subwoofers (sub) demand more power than a factory receiver can provide. Hence, the need for a separate amplifier to provide extra power.

Final Thoughts

Choosing an amplifier for your car speakers will enable you to get the best value for money. You can choose a variable audio filter to have more choice over the sound. This focuses more on factors like power ratings.

Now, you also know why everyone installs amplifiers in their car’s sound system. It is to enjoy a rich sound from your car’s audio system while you drive.