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Are Class D Amplifiers Good for Car Audio Systems?

As anyone who’s ever been to a car audio competition knows, the sound quality of your system can make or break your chances of winning. That’s why choosing the right amplifier is so important.

But what kind of amplifier is best for a car audio system? Class D amplifiers are becoming increasingly popular, but are they any good? Let’s take a look.

The class D amps are the most efficient and are best for powering strong subwoofers. Class D amplifiers are also smaller and lighter than their counterparts, making them ideal for car audio applications, but they do not offer the same sound quality as amps made in AB class.

As an Amazon Associate, ImproveCarAudio will receive a small commission from qualifying purchases made through the links in this article.

Tip: When searching for a good class D amp, get a reputable brand. Otherwise, you may be surprised (not positively) about its performance.

To get more data for the amplifier you are interested in, it is worth checking DYNO tests before purchasing.

In the article below, I will detail the pros and cons of Class D Amplifiers so you can decide whether they are suitable for your car audio system.

What Is Class D Amplifier?

Class d amplifier uses a high-frequency switching process, allowing for a much smaller overall design. This process is known as PWM (Pulse Width Modulation).

class d car amplifier

This differs from other types of amplifiers, where the current always flows in a constant direction.

The advantage of this design is that it is more efficient. This is because there is less heat loss at lower frequencies, allowing for a smaller overall design.

Class d amplifiers are also lighter and create less heat than other amplifiers.

Over the years, they have gained more popularity as they can deliver lots of power, especially those running in MOSFET technology. They are also more efficient in terms of power use, so there is no need to add extra batteries or a stronger alternator in many installations.

Class d amplifiers are able to work with lower impedance loads, making them ideal for subwoofers. Most car audio systems will have at least one subwoofer, and a class d amplifier typically powers these.

In some cases, they are absolute monsters with thousands of watts, like the TARAMPS BASS 30K (link to Amazon) with 30,000W at 1 Ohm.

Taramps Bass 30k 30000 Watts Rms Car Audio Amplifier 1 Ohm

If you want to go extreme or for the competition, check out the TARAMPS HV 160.000 (link to Amazon), which produces 160.000W at 0.25 ohm, but its power supply has to be huge.

TARAMP HV 160.000 will work only with a battery bank because it requires a higher voltage to achieve its full power. According to the manufacturer’s recommendation, it should be a minimum of 24 batteries with 130amp each. 

Taramps HV 160000 1 Channel 160000 Watts Rms Car Audio Amplifier 0.5 Ohm

Class d amplifiers are also less expensive than their linear counterparts. This is because they are simpler to design and cheaper to manufacture.

Let’s look at some of the pros and cons of Class D amplifiers so you can decide if they suit your car’s audio system.

What Are the Advantages of Class D Amplifiers?

Class D amplifiers have a few advantages over other types.

#1. As mentioned earlier, they are more efficient, meaning they waste less power as heat. They are also smaller and lighter, making them easier to install in a car.

#2. Another advantage of class D amplifiers is that they can produce a lot of power. This is great for subwoofers, which need high wattage to operate.

#3. Amps made in Class D have the highest efficiency of all types, up to 90%. This high rate is a big plus, you do not have to buy a large amplifier to produce the energy you want, and class D amplifiers only make a little heat compared to the A or AB equivalents of the same power.

Thanks to constant switching on and off transistors, greater efficiency is possible, as the amp does not consume any energy when they are off.

The high efficiency of the Class D amplifiers leads to more benefits like costs and space savings.

With smaller transistors needed, these amplifiers need fewer cooling areas on the cover; therefore, they can be lighter, better packed, and in effect, cheaper.

What Are the Disadvantages of Class D Amplifier?

#1. The most significant disadvantage of the class D car amps is their sound distortion.

Fortunately, this happens only on the higher frequencies and when amplifiers are not equipped with noise reduction filters, but it is still a potential problem for many car sound systems.

#2. The other disadvantage is the so-called “crossover distortion” that appears when the low pass filter is not set correctly.

If you are looking for an amplifier without any audio quality issues, class AB amps are a better choice.

#3. Another common issue in D-class amplifiers is their interference with AM/FM radio frequencies, which can lead to a total loss of radio signal in certain stations.

This is happening because as you know, the D class amplifiers constantly turn on and off at high frequencies. Unfortunately, those frequencies often overlap with the signal radio stations are broadcasting.

The solution to this problem is to use a signal filter that you can install between the antenna and the head unit of your stereo. This will block high frequencies from reaching the amplifier and, as a result, will stop interference with the audio signal.

The simplest solution is installing an amplifier as far from the stereo as possible, but this is only possible in some larger vehicles. Sometimes, you must add ferrite clips to the amp’s power and RCA wires, especially those with bad shielding.

If adding magnetic filters does not help, the only solution may be to completely shield the amp with aluminum or copper foil or replace it with A/B class or D class equipped with stronger signal filters.

Is Class D Amplifier Good to Power Car Speakers?

Many are wondering what class d amplifiers are used for. The answer is that they are used to power car speakers and subwoofers.

Not long ago, class D amplifiers did not produce the expected sound quality. Although they were powerful, a few models could make sounds to standards tolerated by people who needed something more than just noise.

Even though I see many cars with powerful amplifiers every day, only some are happy with the music quality in their vehicles. A large portion of those cars is not much more than rattling boomboxes.

Modern class D amplifiers have been significantly improved over the years, and producers make constant R & D to ensure they offer better quality. When choosing the right amp for the speakers, it is worth considering the branded product.

For example, great amplifiers are made by JL, JBL, or Rockford Fosgate, to name a few.

Unfortunately, although class D car audio amplifiers have become standard, you still can be disappointed in their quality, especially when choosing cheap, mediocre, quality models.

Class D amplifier is good for powering car speakers because it provides most of the power from all amplifier types available. It is also the only one that fully represents digital amplifiers.

However, as I mentioned earlier, they have a lot of internal distortions that produce lower-quality sounds, so if sound quality is not the highest priority in your car sound system, d class amp will be good enough for speakers.

In many professional car audio systems, class D amplifiers, thanks to their higher efficiency, are used only to power demanding subwoofers.

Although they cause a lot of interference, reducing the sound quality, the bass frequencies do not need as much detail and accuracy as the high frequencies.

This makes class d amplifiers perfect for subwoofers, allowing A/B class amps to make high-end sounds and supply power to the surrounding speakers.

How to Choose the Best Class D Car Audio Amp?

Purchasing the amplifier is straightforward. Just place an order online, and a day after, you have it delivered to your door. But will it be the right amplifier for your system?

When searching for the best amp, we must understand our system requirements and the necessary type.

The amp must match the speakers that you already have. A different approach will be to select an amplifier for the subwoofer, so you have to know precisely what speakers it will power.

There are a few main factors that have to be considered when searching for the best car amplifier, especially when you want to power your car audio with a D-class, and these are:

  • Number of channels
  • Power
  • Impedance
  • Signal-to-noise ratio

Number of Channels

The Monoblock class-D amplifiers have one channel and are used to power subwoofers or, in small portion, single speakers.

In the case of the subwoofers, the high wattage of the amplifier will allow you to create a large amount of solid bass because its small size will easily fit in the trunk.

Class AB amplifiers with the same power are usually over twice as big.

Monoblock Class D amplifiers can also power speakers, but this is rare.

In this type of system, you will need a separate amplifier for each channel, so if you have speakers in each door and a subwoofer, you will need five Monoblock amplifiers, which will take up a lot of space and will not guarantee the best sound quality.

However, there are benefits of using designated amplifiers per speaker, like reduced sound distortions and assigning each transistor to each channel.

Still, this type of system is preferably used by audiophiles but not with class D.

Often chosen amplifiers for specific speakers are A/B amps that produce sounds of higher quality.

More popular are multi-channel class D amplifiers, and these are either 2, 4, or even 6 channels.

The benefit of the multi-channel amplifier is space-saving when connecting the whole car audio system to one power station. Another good point is that most class D amplifiers with two or more channels can connect a subwoofer to one bridged channel.

For example, when you have a 4-channel amplifier, you can power 4 speakers in a car or one pair of speakers and a powerful subwoofer.

Two-channel amps are used in simple car audio applications to power one pair of speakers or a single subwoofer.

Power

When it comes to power, you should have more of it rather than not enough.

Although there are two main power ratings in the car audio world: RMS power and Peak power, we will always talk about RMS power, which is sustainable and means how much continuous power an amplifier can produce, or speaker can handle.

Because it is worse for speakers when underpowered rather than overpowered, the amplifier should produce speakers’ RMS as a minimum.

How much is the maximum, though?

It is recommended to be at most 150% of the speakers’ power handling, so if you have speakers with 100W RMS each, an amplifier should be between 100W and 150W RMS per channel. The higher ratio should go towards powering subwoofers.

Impedance

Impedance is critical when it comes to producing stable power; simply speaking, it should be the same on the speakers and amplifiers.

When you have speakers 100W with 2 ohms, do not buy a 100W amplifier with 4 ohms unless you want to fry it.

In the case of standard speakers, the impedance must match when you connect just one speaker per channel, which is either a coaxial or component system.

While a 100W 4-ohm speaker will demand a 4-ohm amplifier to supply 100W, a low impedance 2-ohm speaker will try to pull from the same amplifier 200W.

Signal to Noise Ratio

The signal-to-noise ratio is essential when defining how loud the amplifier is compared to the sounds it produces.

The last thing you want to hear after installing a high-end audio system is background noise while trying to enjoy your music. Therefore the higher value of the SNR, the better.

The typical signal-to-noise ratio for class D amplifiers is around 80 dB for multi-channel amplifiers and approximately 75 dB for mono amplifiers.

Remember, the higher the value, the fewer background noises you will hear, and the speakers’ sounds will be more precise.

Below are examples of signal to noise ratios in popular amplifiers:

  • Rockford Fosgate R2-500 X4 – 80 dB
  • Rockford Fosgate R2-750 X1 – 70 dB
  • JBL Club 704 – 85 dB
  • JBL Club 5501 – 80 dB

Summary

Class D amplifiers have no life in the audiophile world, where every tone has to be precisely selected and reproduced.

They cannot compete with much more accurate A or A/B amplifiers. Also, they have internal sound distortions at higher frequencies, so if you want to hear perfect sounds in your favorite tracks, class D, although very efficient, is not the best choice.

However, they are fantastic for powering subwoofers and supporting mid-bass frequencies or any system in which other class amplifiers support high-end high tones.

Class D amplifiers are also a good option for small cars, or convertibles, where even with a closed roof, there is a lot of noise when compared to vehicles with a hardtop.

Regardless of which type of car audio application, you will use an amplifier, remember the speakers’ requirements, and choose the suitable model for the best music experience.