Factors To Consider While Choosing a Car Amplifier (Buying Guide)

Last Updated on March 4, 2024 by CarAudioHunt

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What car amplifier to buy? It is a common question even for experienced car enthusiasts. We tried to answer this question in the most simplistic manner.

Choosing the right car amplifier is about more than preference and budget. It needs stronger scrutinization like the amplifier’s dimensions, power output, class, channel, and speaker compatibility. We will explain and teach you these determining variables so that you can make an informed decision and really understand how to choose a car amplifier.

But, before that, you should understand the core functionalities of an amplifier and consider why you might need it. Understanding these two questions will help you later in choosing the right amplifier in your budget.

A car amplifier comes in handy when you have a low-power audio signal like a radio, CD player, or smartphone. It amplifies the weak signal before sending it to the car’s speakers, resulting in louder and clearer sound.

Besides that, the additional power boost helps the speakers to reproduce sounds with greater fidelity. This is especially noticeable with high-quality recordings and in the nuances of different types of music.

When a stereo system is pushed to its limits without an amplifier, it can cause distortion - a crackling or buzzing sound that occurs when speakers attempt to produce sounds at volumes or frequencies they can't handle. A car amplifier gives the speakers enough juice to play loud music without distortions.

Do I Need a Car Amplifier?

Now that you know what a car amplifier really does, it is easier for you to decide whether you need one or not. Let’s give you a heads-up.

Before diving into the details, just remember for your amplifier to deliver at its max, it must be accompanied by an outstanding set of speakers.

  • If you are an audiophile, then you will find the factory system lacking in many terms. Generally, the factory system does not include a dedicated amplifier, though it may have one integrated with the stereo. Also, the speakers are often of average quality. You can use a dedicated amplifier to compensate for these lackings.
  • If you've already upgraded your car's stereo system with aftermarket components, adding an amplifier can further enhance its performance. Aftermarket speakers, in particular, can often handle more power than factory speakers, making them ideal candidates for amplification.
  • If your current system cannot cope with high-volume music, an amplifier can provide the extra power needed to maintain clarity at louder levels.
  • If you want to add a subwoofer or improve the bass in your car audio system, a mono-amplifier is almost always necessary. Subwoofers require more power than typical speakers, and an amplifier can provide this.

5 Core Factors To Consider To Choose a Car Amplifier

We can now discuss the rudimentary elements that make up the perfect amplifier match. Please keep in mind that, there are uncountable variables in deciding the best amplifier for your car audio system like your budget, your housing space, and your music preference. Keeping these subjective matters aside, we now dive into the most important factors.

1. Compatibility with the Head Unit

Assuming that you already have a satisfactory head unit, the amplifier must complement the existing stereo.
The head units have preamp output or RCA output that must align with the external amplifier. Without these, an adapter or speaker level inputs on the amplifier will be needed, potentially affecting sound quality.

The amplifier's power should match with the head unit's output. An overly powerful amplifier is meaningless as it won’t be able to use its maximum capacity, while an underpowered one won't significantly improve sound quality.

The impedance (ohms) of the speakers and amplifier must match what the head unit supports. Mismatched impedance can result in poor sound or damage to the system.

Consider Compatibility between head unit and amp

2. Amplifier Channel

How the number of channels impacts your car audio experience is a discussion itself and yet very crucial for selecting the suitable amplifier.

The rule of thumb is to dedicate each channel to each speaker, meaning the number of channels and the number of speakers should be the same.

For your ease of understanding, we have summarized it in TYPES OF CAR AUDIO AMPLIFIERS. Read the article to have a better insight into what to choose.

The number of channels in an amplifier influences how power is distributed across your audio system. More channels mean a more even power spread, allowing each speaker or subwoofer to perform at its best without overburdening the amplifier.

Multi-channel amplifiers often come with advanced control options, like separate gain controls for each channel, enabling finer sound customization. This leads to a cleaner, more distinct soundstage, elevating your listening experience. But they also have higher costs associated with them. Opting for a single multi-channel amplifier can be more economical than multiple single or dual-channel amplifiers for the same system configuration.

Consider Amp Channel before You Buy

3. Amplifier Class

Amplifier class is more of a technical matter that cannot be witnessed physically. You will have to check your amplifier configuration and label details to find out your amplifier class.

There are several classes of car amplifiers and we have scrutinized them in our CLASS OF CAR AUDIO AMPLIFIER article. But, for now, let us give you a brief summary.

  • If you prioritize high-fidelity sound with minimal distortion, a Class A amplifier offers the best sound quality. However, its inefficiency and heat production make it less practical for car audio.
  • For a balance of sound quality and efficiency, you may choose Class AB amplifiers. They provide good sound quality with reasonable efficiency, suitable for most car audio enthusiasts.
  • If sound quality is less of a priority and you need an amplifier for specific applications like driving a subwoofer, Class D amplifiers are highly efficient and compact, making them ideal for such purposes.
  • Class D amplifiers are highly efficient and produce less heat compared to Class A or AB, making them suitable for compact car spaces.
Consider Amp Class Before Buying

4. Power Requirement

The amplifier's power output should match the power handling capability of your speakers. You may look at the RMS (Root Mean Square) power ratings, not just the peak power ratings.

Please remember to look for an amplifier whose RMS power per channel is close to the RMS power rating of your speakers. Some key rules are -

  • For those seeking the highest impact and volume, an amplifier with 100 watts RMS or more per channel is advisable.
  • For larger vehicles or those who prefer louder music, stepping up to an amplifier with at least 75 watts RMS per channel is recommended.
  • For compact cars, sports cars, or small-cab pickups, an amplifier with 50 watts RMS (Root Mean Square) per channel is typically sufficient.

We will advise you to keep some headroom for power, meaning having a bit more power than your speakers' rating to ensure clean and distortion-free sound at all volumes.

5. Size

Amplifiers come in various sizes, and there is no point in buying one that won’t fit your vehicle. Therefore, it is crucial to measure the available space in your vehicle, like under seats or in the trunk, and compare it with potential amplifiers. You will have to make sure that there is enough space around the amplifier for proper ventilation to prevent overheating.

Wrapping Up

In the whole car amplifier buying guide, we have explained what car amplifier you should buy and the key factors to consider while purchasing.

When choosing a car amplifier, consider the number of channels you need based on your speaker setup, ensure the power ratings match your speakers' requirements, verify system compatibility with your existing audio components, and choose a size that fits well in your car with adequate ventilation. Balancing these factors will help you select an amplifier that effectively enhances your car audio experience. 

Though these considerations will solve most of your problems, you will still have to hunt for the perfect amplifier for your car. We have recommended and reviewed numerous aftermarket amplifiers. Let's check them out:

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