Skip to main content

4-channel power amplifiers deliver plenty of power and supply up to four speakers with a high-quality audio signal. This is how you get the most out of your car’s sound system.

A configurable 4-channel power amplifier can be bridged to three and two channels and will thus pass your practical test. Do you want to connect with a subwoofer? Then choose a 4-channel power amplifier with low-pass and high-pass filters from our comparison table now.

The most important in a nutshell

  • A 4-channel power amplifier is an amplifier that distributes the incoming audio signal to four channels and then amplifies it. This allows you to use up to four speakers simultaneously.
  • Speakers that produce low frequencies and have to move a lot of air to do so, such as woofers and subwoofers, require a lot of power. This is supplied by a 4-channel power amplifier.
  • With a 4-channel power amplifier, you can also operate a setup that only has two or three speakers. To do this, you connect two channels together and can thus use the power of both channels.

Does a 4-channel power amplifier provide power for up to four speakers?

A 4-channel power amplifier is an amplifier for audio signals. You connect your 4-channel power amplifier between the sound source, for example, the car radio, and the speakers. The signal from the sound source is usually stereo, i.e. two channels are output (left and right). These are each divided and amplified by the 4-channel power amplifier, giving you four channels.

You benefit from the installation of a 4-channel power amplifier for a better performance of your speakers. The amplifier with four channels will sound better than the one that is in your car from the factory. Since 4-channel power amps are very powerful and deliver up to 1,200 watts, you can now install speakers that require a lot of power to operate. In addition, the two extra channels give you the option of connecting two more speakers or a subwoofer.

Do configurable channels provide additional power and flexibility?

The multi-channel amplifiers of many brands offer configurable channels. Thanks to this feature, the channels can be bridged, i.e. connected together.

Such a multi-channel power amplifier can be used in the following configurations:

  • 4-channel power amplifier.
  • 3-channel output stage (two channels bridged).
  • 2-channel output stage (four channels bridged).

A four-channel output stage can thus also be used as a 3-channel output stage and a 2-channel output stage.

The channel created by bridging two channels not only theoretically has the power of the two channels that were bridged together. 4-channel power amplifier tests prove that the bridged channel has twice as many watts as a single channel.

Configurable channels are especially useful if you want to add a subwoofer to your car’s sound system. Subwoofers move a lot of air and need a lot of power to do so. Also, a subwoofer needs to receive the signal from both stereo channels to fully reproduce bass. Bridge two channels of your amplifier and connect that channel to your subwoofer, and it will be supplied with enough power and receive information from both the left and right stereo channels.

If you want to connect a subwoofer to your car’s HIFI sound system, you’ll need a 4-channel power amp that can be configured to three channels. If you want to drive two particularly power-hungry speakers, we recommend a 4-channel power amplifier that can be configured to 2 channels.

4 Channel Amp – Best Choice

Best choice

Blaupunkt 4-Channel Full-Range Amplifier

This slim amplifier fits perfectly into any trunk so you can easily connect it to your stereo system. With an optimized 150-watt RMS output, you can give your music a huge boost in power that will have you and your passengers partying while on the road.

4,6 Rating

  • Max. Output Power – 1500W x 4.
  • Frequency Response – 10Hz – 45Hz.

Best 4-Channel Amplifiers on the market:


Rockford Fosgate Prime 4-Channel Amplifier



  • Rating: 4,7 ∗∗∗∗∗
  • On-board Punch EQ with +18dB boost at 45Hz.
  • Works with factory installed & aftermarket source units.


Rockford Fosgate Full Range Class-D 4-Channel Amplifier



  • Rating: 4,7 ∗∗∗∗∗
  • On-board Punch EQ with +18dB boost @ 45Hz.
  • RCA pass-thru outputs.


PIONEER Class FD 4-Channel Bridgeable Amplifier



  • Rating: 4,6 ∗∗∗∗∗
  • Max Power: 1,200 Watts.
  • Frequency Response: 10 Hz – 50 kHz.


Kenwood Excelon 4-Channel Car Amplifier


  • Rating: 4,8 ∗∗∗∗∗
  • Frequency Response: 20Hz-50kHz.
  • Speaker Level Input with Signal Sensing Turn-on.

Buying criteria


The power is probably the most important feature of an amplifier, and so the manufacturers outdo each other with the highest possible values. However, the stated value is the maximum power that the amplifier can output in the short term.

The 1,000 watts that a multi-channel amplifier has at its disposal are therefore not called up permanently.

What the maximum power looks like in normal operation is indicated by the RMS value, also in watts. However, this is significantly lower and is rarely communicated by the manufacturers.

The manufacturers also state how much power each individual channel has. Here, too, the maximum value is given and not the RMS value. The power per channel depends on the resistance of the connected speaker. This is specified in ohms. Since speakers for the car usually have a resistance of 2 or 4 ohms, the 4-channel power amplifiers are also designed for this.

The following applies the greater the resistance, the lower the power of the audio amplifier.

If you want to use boxes with a resistance of 4 ohms, you should go for a powerful amplifier.

If you don’t want to install new speakers, but just want to add a subwoofer to the existing car HIFI system, you can buy a cheap 4-channel power amplifier. Already, power amplifiers with 600 watts provide sufficient power. If you build in a completely new and achievement-hungry Car HIFI system inclusive subwoofer, we recommend a 4-channel final stage with at least 1,000 Watts to you. These are well-suited as subwoofer amplifiers.

High-pass and low-pass

A subwoofer is responsible for the bass, i.e. the low frequencies, in a hi-fi system. These lie in the range from 10 to 200 Hertz. Mids and highs, which are located in the frequency spectrum above the basses, cannot be reproduced cleanly by a subwoofer. Therefore, it is important to filter these out of the signal that is applied to the subwoofer. This task is performed by a low-pass filter.

A low-pass filter allows only the low frequencies to pass through, and so the subwoofer reproduces only the bass. Higher frequencies are played by the other speakers. Since the bass frequencies are now reproduced by the subwoofer, they can now be filtered out of the signal that goes to the other speakers. This is done with a high pass filter.

If you want to use a subwoofer, you need a 4-channel power amplifier with high-pass and low-pass filters.

The following table gives you information about the designation of the frequency ranges:

Controller designation: Frequency range:
bass 0 – 200 Hz
low mids  200 – 1,500 Hz
high mids 1.500 – 4.000 Hz
treble  4.000 – 12.000 Hz

DSP chip

DSP stands for digital signal processing, which can be translated as digital signal processing. A DSP chip converts the analog signal into a digital one, processes it in real-time, and converts it back into an analog signal, which is then amplified. The term digital power amplifier usually refers to power amplifiers with a DSP chip.

4-channel power amplifiers with a DSP chip offer the possibility to change the sound specifically. In most cases, the chip acts as an equalizer and ensures that the sound sounds as round as possible. Since the chip works digitally, you can connect your power amp to a computer or use your smartphone to determine how the signal should be changed.

If you want maximum control over the sound, you’re well advised to go with a 4-channel power amp that has an integrated DSP chip. This way, you can change the sound of your car sound system without having to buy additional accessories.

These are the advantages and disadvantages of a 4-channel power amp with a DSP chip over one without:


  • Sound can be adjusted exactly to your own preferences.
  • Control via computer or app is possible.


  • Higher purchase price.

When do you need a 4-channel power amplifier and when a 2-channel power amplifier?

As the name suggests, a 4-channel power amplifier has twice as many channels as a 2-channel power amplifier. For each speaker you add to your sound system, you need one channel of your power amplifier. If you have a normal stereo setup, you need a two-channel amplifier. On the other hand, if you want to use four speakers, you need four channels.

Subwoofers are an exception. On the one hand, they need more power than an ordinary speaker, and on the other hand, you need to receive the audio signals of both stereo channels in order to reproduce the bass properly. Therefore, to connect a subwoofer, you need two channels, which you have to bridge.

What needs to be considered when connecting a subwoofer?

When connecting a subwoofer to your sound system, you must first bridge the correct channels. You need one of the two left stereo channels as well as one of the two right stereo channels. This is not a problem, especially with configurable 4-channel power amplifiers.

Furthermore, you must make sure that you activate the low-pass filter on the two channels that you have bridged. Often this is called low-pass. On the remaining two channels you now activate the high-pass filter, which is usually called high-pass.


Don’t be confused by high wattages. This is irrelevant. Rather, make sure that each unit is really matched to the other. Get help and advice on installation. Everything must be matched to your car. There are big differences between old and new car models.

Sometimes the connections are different. It is better to have the installation done in the workshop. You should only do it yourself if you are really able to do it. All connections must fit together perfectly. Safety should be your first priority in this context. The fuses in particular can be tricky if you don’t know enough about them. In the end, you know best what is good for you and what your wallet can handle.

PIONEER 4-Channel Bridgeable Amplifier - Video

Max Welder (rvneeded)

Max Welder (rvneeded)

Max Welder is a mechanic enthusiast. Currently, working at a small company. Experienced in electronics, car tools, and security systems. In his spare time, he writes articles for various blogs.

Leave a Reply