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How to Choose Amplifier for Speakers?

How to Choose Amplifier for Speakers

You might be wondering why your music sounds so flat when you are playing it in your car. In cases like this, most of us think that the problem lies in the speakers. However, that might not be the case. Sometimes a good amplifier can solve this problem.

The amplifier will provide enough power for your speaker to function smoothly. You will no longer hear flat sounds if you invest in a good amplifier for speakers or subwoofer.

Why you Need Amplifier?

1. Sound Quality

An amplifier makes the sound quality better. It provides clean power for your speakers. The sound will be clearer, and the quality will be good, not like an in-dash stereo.

The sound quality from an amplifier is much more clean and smooth. The details and levels of music will be more audible than before.

2. Power

The default speakers or in-dash speakers are not that great quality. They will not serve justice for your high-quality speakers. If you have upgraded your speakers, you will need a more powerful receiver to see it’s true potential. Amplifiers will provide enough power for your upgraded speakers.

3. Subwoofer

If you have or want to have a subwoofer, you consider adding an amplifier. Subwoofers need significantly more power to operate. The subwoofer needs more power than a default or in-dash receiver can provide. Therefore, using an amplifier becomes mandatory.

Amplifier for size and shape

How to Choose an Amplifier for Car Speakers?

You need to keep in mind several things or look for before buying an amplifier for your car speakers. In the following passages, we will further discuss the things to know before making a purchase.

1. Matching Amps to Speaker

The major reason a person purchases an amplifier is for the speakers or sound system. If they do not match, they will not function properly. Your whole purchase can become a waste of money and time. You must check whether the amp you are planning to buy is compatible with your speakers.

Even if your amplifier and speakers work together, they might sound the best. There could be noise, distortion if they are not suitable for each other. We will discuss more the criteria that need to match before finalizing a purchase.

2. Impedance

Impedance measures electrical resistance. If your speakers or subwoofers do not match with the amplifier, you will not get smooth output. For smoother electrical flow, you need to ensure the same impedance.

Suppose you want to buy two 8-ohm speakers, so you have to buy a 16-ohm amplifier. Otherwise, your system will not properly. It can overheat or produce bad quality sound.

3. Channels

There are many different types of amplifiers you can buy. Depending on how many speakers or subwoofers you want to have, you should choose an amplifier. Generally, there are 6 types of amplifiers.

Mono-Channel Amplifier

Mono-channel amplifiers are mainly designed for subwoofers. Subwoofers require a mono amplifier. This has a single channel, which means the audio is processed through only one channel.

With a high RMS rated mono amplifier, you can use multiple subwoofers. High-quality mono amplifiers can filter noise and control tone, which providesthe best quality and bass.

2 Channel Amplifier

These amplifiers have two channels, as the name suggests. You can use 2 channel amplifier for two stereo speakers. Alternatively, you can bridge both the channels and install a subwoofer. 2-channel amplifiers are divided into two types, which are Class A and Class AB circuits.

Class A amplifiers have a single transistor. It sends a sound impulse through the single transistor. You can get a clear and distinctive sound which is very good quality.

However, it produces a lot of heat and consumes a lot of energy. The other type, Class AB, has two transistors instead of one. As it divides the workload among two transistors, it is more energy-efficient and reliable.

3 Channel Amplifier

3-channel amplifiers are mainly a combination of two amplifiers. Among the three amplifiers, two of them are used to power the speakers, and the other one is connected to the subwoofer.

If you are willing to purchase a sound system with two speakers and a subwoofer, a 3-channel amplifier would be the best. This type also has two subdivisions. One is the Class AB circuit, and another is the Class D circuit.

This type is a decent one at an affordable price. It is also one of the popular ones. However, if you are looking for something that offers something extra than ordinary, you should look for other types of amplifiers.

4 Channel Amplifier

4 channel amplifiers are the most popular ones. They provide the best sound quality at a competitive price. It uses two channels for two speakers and the rest two for a subwoofer.

Alternatively, it can also use four channels for four speakers. You can get good quality, noise-free music from this amplifier.

5 Channel Amplifier

Like the 3-channel amplifier, a 5-channel amplifier is also a combination of two types of amplifiers. It consists of a 4 channel amplifier circuitry and a mono-amplifier circuitry. The 4-channel amplifier works with four speakers, two in the front and two in the back.

The mono-amplifier is the most powerful one in this system, which is why it powers up the subwoofer. You will get great quality sound from a 5-channel amplifier.

 6 Channel Amplifier

This the most powerful one yet not the widely used one. It is suitable for bigger vehicles, that is why people do not use it much. It has six channels. You can either use it as four channels for four speakers, create a bridge among the rest of the two channels, and use it for a subwoofer.

Another option is using it for six individual speakers. 6 channel amplifiers can be used in trucks, bigger high-end cars, SUVs, and provide great quality sound but will need more space.

4. Amp Class

As we have already mentioned, some amplifiers are divided into different classes depending on their electronic circuit. It determines the sound energy efficiency and heat generation. There are four types of classes; they are A, B, AB, and D.

Class A amplifiers provide great sound quality. However, they are not recommended as they make a large amount of energy waste and generates heat. In terms of efficiency, Class B is better than Class A. However, it is not the best and has some drawbacks. Transistors keep switching on and off, which causes cross-over distortion.

Class AB is the best solution for all the classes. They are a combination of both Class A and Class B, minus the drawbacks of them. It does not waste energy and has no cross-over distortion.

5. Power Rating

The purpose of getting an amplifier is to have enough power for your speakers. If your speakers don’t get enough power, they might get damaged. Your speaker’s Root Mean Square (RMS) can be a good indicator for you to decide what will be best for your car.

If you want a sound system that will provide good quality music and will keep the balance between other systems, you need to follow some rules. They are as following.

  • For car’s factory stereo, for the bass 50 to 200 watts, RMS will work fine.
  • For the subwoofer, you might need 200-300 watts RMS.
  • For amplified speakers with 50 watts RMS per channel, you will need 250-500 watts RMS for bass.
  • For a 100 watts RMS or higher power channel, you will need a system minimum of 1000 watts RMS for your sub.

It is recommended to use an amplifier with a power output of at least 75 to 150 percent of the RMS value.

6· Size and Space

Before purchasing an amplifier, you need to think about the available space in your car. Most people do not consider car space and only look for the specifications of the car. You need to consider the size of the vehicle. The effect you get in an SUV will not be the same as a small car.

Firstly, an amplifier is an external attachment, and you have to allocate space for the amplifier. Usually, an amplifier is installed in the trunk, under the seat, or on the sidewalls of the passenger seat. These places have enough space to install an amplifier and wire properly.

Different amplifiers come in different sizes. However, small amplifiers do not mean poor quality. So you do not need to worry about buying a smaller amplifier for your smaller car. It is best to measure your car’s free space where you want to attach your amplifier and then buy one suitable for your car.

7· Brand

There are many amplifiers available in the market. Not every one of those is good. If you are actually thinking about purchasing an amplifier, you should think about investing in a good one.

Even if it cost a few extra dollars, it is still better to buy a good one that will last longer and provide better service. Good brands ensure good quality and safety. Some of them also come with a better warranty and return policy.

8· Budget

Budget becomes the key factor when it comes to any purchasing. You can spend thousands of dollars for a high-end amplifier, or you can get one in a few hundred dollars. It totally depends on you how much you are willing to pay.

It is better to look for something that fulfills your requirement for both specifications and price. You can even consider buying a second-hand amplifier if you wish.


You need to find an amplifier that has RMS and impedance that matches your requirement. Hopefully, you are now aware of what you need to consider before purchasing an amplifier for your car speakers, as we have already discussed how to choose an amplifier for speakers.