Best 4 Channel Car Amplifier

The problem with purchasing a new vehicle is that the factory stereo system is always going to be a bit underwhelming. If you enjoy listening to good music while driving, you might have to add a few accessories to improve your car audio.

The amplifier is at the heart of any sound system and can easily be the difference between boring, low sound quality and booming, high-fidelity audio in your car. 

But figuring out the best amplifier option on the market can easily take you down the rabbit hole. That’s why we’ve done the research for you to find the ideal accessories to take your factory stereo system to the next level.

Below, we review the best 4 channel car amplifier!

In a hurry? After 30 Hours of Research, We Recommend:

Alpine X-A70F X-Series 4/3/2 Channel Power Density Amplifier
our score

Why it is better?

It is a highly efficient device that comes with high-performance specs to take your car stereo speakers from boring to banging. The major highlights on the Alpine X-A70F include:

  • Class D amp
  • 90+% efficiency
  • 0.05% Total Harmonic Distortion
  • 120W rms x 4 at 4 Ohms or 175W rms x 4 at 2 Ohms
  • 106dB signal to noise ratio
  • Variable low and high pass filters
  • Bass EQ
  • Continuous thermal control






hours researching


products compared

Last Updated: October 2023

By Barry Allen: This article has been updated to reflect the most accurate information regarding best center channel speakers available for those who are interested in ramping the quality of their sound up. The best 5 available have changed, and information has been added to assist individuals in finding the best center channel speakers currently available on the market. The FAQ has also been updated.

Best 4 Channel Car Amplifier – Comparison Table 





Our Rating

Current Price

Alpine X-A70F X-Series 4/3/2 Channel Power Density Amplifier

Best Overall

Alpine X-A70F X-Series 4/3/2 Channel Power Density Amplifier





Planet Audio AC1200.4 4 Channel Car Amplifier

Best Budget Option

Planet Audio AC1200.4 4 Channel Car Amplifier





Kenwood KAC-M3004 Compact 4 Channel Digital Amplifier

Kenwood KAC-M3004 Compact 4 Channel Digital Amplifier





Alpine MRV-F300 4-Channel Car Amplifier

Best for Small Spaces

Alpine MRV-F300 4-Channel Car Amplifier, 50 Watts RMS x 4





BOSS Audio Systems R1004 4 Channel Car Amplifier

Least Budget

BOSS Audio Systems R1004 4 Channel Car Amplifier





Rockford Fosgate P600X4 Punch 600 Watt 4 Channel Car Amplifier

BOSS Audio Systems R1004 4 Channel Car Amplifier





Pioneer GM-A6704 4-Channel Bridgeable Amplifier

BOSS Audio Systems R1004 4 Channel Car Amplifier





Best 4 Channel Car Amplifier Buying Guide- Factors to Consider

Class and Efficiency

When you start shopping for an amplifier, you will come across the word “class” being used to differentiate models; but what does it mean? Well, there are four major classes of amps: A, B, A/B, and D. What distinguishes one from the other is efficiency. 

Efficiency in amplifiers refers to a measure of how much AC (Alternating Current) an amp can pass to another component while using the least amount of DC (Direct Current). Because of the differences in circuitry, efficiency tends to vary from one class of amp to the other. 

Class A

Given the simple design of their circuit, Class A amps conduct electricity all the time. This results in this class of amplifiers offering the purest signal of all classes. 

This is the major benefit of Class A amplifiers, but on the downside, continuous conduction results in two major disadvantages: Just a small fraction of the electricity is harnessed by the speakers, meaning the efficiency of a standard Class A amplifier is significantly low, 30% to be exact. 

The surplus electricity is therefore conducted to heat energy. For this reason, most Class A amplifiers end up overheating when used for an extended duration. 

Class B

Class B type of amplifiers will only conduct electricity about half of the time. The implication is that the excess electricity wasted is notably reduced, which in turn, increases the efficiency. Overall, Class B amplifiers offer an efficiency of 70%, but the major drawback of these amplifiers is in the way their circuits are set up. You will have to do with a small amount of distortion. 

Class A/B

Class A/B amplifiers combine some attributes of Class A amps with those of Class B amps. Despite featuring a Class B in setup the circuit, Class A/B amps don’t have any distortion issues. This is credited to the inclusion of biasing diodes that cancel them out. 

The benefit of Class A/B amps is that they offer the best of two worlds. You enjoy the signal purity from Class A, as well as the power efficiency of Class B!

Class D

This category of amplifiers delivers the highest efficiency at 95% due to the fact that they are output transistors, hence don’t retain any electricity when the amp is turned off. As a result, there is no surplus of electricity to be converted to heat. On the flip side, D amp class has the lowest signal purity compared to all the other Classes of amplifiers. 

Power Output

The main role of amplifiers is to supply more power to speakers. This is how they boost the signal and make the speakers louder. So, if you like to play your car audio at full volume and shake things up with a bang, then you need the most power from your amp. However, each speaker has a limit in as far as the power it can handle. 

Breaching this limit implies that the speaker’s internal components are exposed to the risk of damage. Two main metrics on a speaker will give you an idea of the unit’s power handling capabilities: Peak Power and Maximum RMS. 

The maximum RMS of a speaker refers to the amount of power (in watts) that a speaker unit can safely receive and handle continuously. The peak power on the other hand will tell you the absolute limit when it comes to how much power your speaker can handle. 

In essence, the peak power is the point of no return. Going beyond this threshold is a sure way of blowing out your speaker, causing irreparable damage. Usually, amplifiers will have both Peak Power and RMS ratings, but will also specify the power output. 

Therefore, before buying an amplifier to install on your car, ensure that the RMS of the car speakers is equal to or greater than the one on the amp, and the same applies to the peak power. This will avoid situations where you end up blowing your speakers with booming music. 

Speaker Sensitivity

This refers to a measure of how loud (decibels) a speaker can get when you decide to run it with one watt of power. For instance, if your speaker has a sensitivity of around 80dB, it implies that it will sound pretty loud if you supply it with just one watt of power.

Such a speaker can produce a decent amount of sound, and for every extra watt you supply, you get 3dB worth of additional volume. Speaker sensitivity will allow you to gauge how much power output to go for when choosing an amplifier. 

If your car speaker is very sensitive (assuming it’s rated at 90dB), this means you won’t need an amp that’s too powerful given that the speaker can produce a fair amount of sound without too much power behind it. 

However, if your speaker has a low sensitivity rating, then it will require more power to get to the same level of volume.  

Frequency Response

The frequency response will give a range between the highs and lows that an amplifier will be able to handle. Some amplifiers can handle the full audible spectrum- 20HZ to 20KHz but others will only process bass sound signals- 20Hz to 250Hz. The latter is designed for subwoofers while the latter is meant for all kinds of speakers.

Number of Channels

Before you buy an amp, you’ll have to establish the number of channels you need it to have. You can do this by checking how many speakers are in your car and their type. For example, if your vehicle has two stereo speakers on either car door, then you’ll require a stereo two-channel amp to get the right performance. 

Dual stereo amplifiers will transmit a signal to the right and left channel separately, which results in more accurately panned audio. The instrumentals in the song are optimally positioned for the best sound quality. 

On the other hand, mono channels transmit both the left and right panned signals together. A mono channel amplifier will be suitable if you only have one speaker. So, if you’re getting an amp to power a subwoofer, then a high-powered mono-channel unit will do. 

However, it is possible to bridge a dual-channel into a single channel mode with the ability to supply greater power. 

Now that you know what to look for when buying a car amplifier let's look at our individual reviews for the best 4 channel car amplifiers.

Best 4 Channel Car Amplifier

Alpine X-A70F X-Series 4/3/2 Channel Power Density Amplifier
Our Rating: 92/100

Alpine is one of the established brands in the industry when it comes to producing car audio accessories. It is no surprise that the X-A70F sits at the summit of our list of best 4 channel car amps. The amp features an array of high-quality specs and performs excellently compared to most of the other amps on this list.

But then again you pay for what you get! That’s why aside from being our number one pick, it is also by far the most expensive 4 channel amp we will review! 


The Alpine X-A70F X-series amp has set the bar high with an all-new and upgraded digital architecture to deliver high sound quality with unrivaled accuracy, purity, and power efficiency. 

Measuring 15 x 11 x 7 inches, it is a relatively bulky package and its 3.2kg weight adds to the hassle of installing it inside your car. 

The design further features an innovative aluminum heat sink with a bespoke airflow system. This serves to keep the amp cool when it's running to maintain performance at its peak. It allows for hot air to rise from the top as cool air is drawn in from the bottom. 

As a result, you get optimal thermal control that lets you enjoy high-level power output without worrying about the amp shutting down.

The Performance

This amplifier is built for true high-resolution audio playback and you can tell this from its broad 10Hz-60kHz frequency range. Also, the X-A70F comes with unmatched staying power and a high damping factor for superior control.

There is virtually zero distortion in the stereo, enabling for highly accurate low-frequency output and an overall top sound quality. The amp has very low background noise at 115/106dB with a THD at 0.05%. 

It further boasts an RMS rating of 120 watts x 4 at 4 Ohms or 175 watts x 4 at 2 Ohms, meaning you get enough sound power to bust the windows of your car. This Class D unit employs the fresh Alpine-proprietary circuit design to achieve leading power density and dependability. 

The simplified circuit topology ensures the cleanest signal path, leading to a great sound quality. Furthermore, an exclusive double feedback loop is integrated to correct any signal distortion. We also like the power efficiency of above 90% in this amp.

On the downside, this is one of the larger units on our list, so you need good space to install it. Also, the input sensitivity is slightly narrow at 400 mV to 4 volts, which may call for newer signal transmitters or head units. 

Other impressive features of the X-series include a built-in variable low and high pass filter, bass EQ, as well as remote level control. Overall, this is a remarkable amp option if you’re looking for the best car sound quality performance and have no expenses to spare! 


  • Wide frequency response
  • Low to no distortion
  • Very efficient
  • Impressive power
  • Low and high pass filters
    Continuous thermal control/heat sink


  • Expensive
  • Slightly bulky
Planet Audio AC120
Our Rating: 87/100

If you don’t want to break the bank when buying a new amplifier for your car sound, this unit might just be the best deal you’ll find on the market. It will cost you less than $100 yet still offers a more-than-decent sound quality upgrade, making it the best value for money 4 channel car amplifier on our list. 

Despite its entry-level price, the AC1200 offers everything you want in a car amplifier to improve your car sound system!

The Design

The AC 1200 measures 11" x 10" x 2.4"; it is compact enough to fit inside the trunk without cramping things up. However, you may run into some difficulty trying to fit it under a car seat or any other tight spaces in your vehicle. At 3.2kg, it is one of the heaviest 4 channel amps out there. 

The Planet Audio amp comes with the same design as that of the parent Boss company brand. It features a sleek-looking black housing with the “Planet Audio” logo stamped in the middle of the upper chassis.

It is a very durable amplifier thanks to an integrated thermal protection circuit that turns off the amp when it gets too hot. 

In the event a speaker setup fails and causes an electric short, the protection circuit automatically cuts the output and stays in this state until the issue is solved. This self-protection feature helps to give you peace of mind whenever the amp is running. 

The Performance

The AC 1200 sounds as great as it looks. If you are searching for something to power four small speakers, it will be a nice option for you. This amp comes with a max power output of 1200W and a rating of 113W RMS x 4 into 4 Ohms and 225W RMS x 4 into 2 Ohms, or it can be bridged into 450W RMS x 2 into 4 Ohms.

It also consists of high/low 12dB crossovers, as well as an adjustable 0-18dB bass boost on the ¾ channels. With both high-level and low-level inputs included, this amplifier offers you the flexibility to set up an audio system using both a standard factory and aftermarket car stereo unit. 

High-level or speaker level inputs are those that accept a signal from speakers whereas low-level inputs receive the signal from pre-amp outputs of the source unit. The amplifier also uses a MOSFET power supply, which allows switching from full to non-conductivity, ensuring high-efficiency output.

The AC 1200 is a Class A/B amp, meaning it employs linear circuitry to enhance the sound quality, and power output while also reducing distortion. A fixed high pass crossover, as well as a variable low pass crossover on the amp, enables you to isolate the highs and the lows, ensuring that you enjoy the best audio quality. 

Although it may not be on the level of the more costly units on our list, the Planet Audio AC 1200 offers enough power to give you a satisfying listening experience. 


  • Thermal protection circuit
  • MOSFET circuity for high efficiency
  • Variable low pass and fixed high pass filters
  • Very affordable
  • High- and speaker level inputs
  • Solid construction
  • Variable bass boost
  • 60-day money-back and 1-year warranty


  • Runs hot
  • Kind of bulky
Kenwood KAC-M3004 Compact 4 Channel Digital Amplifier
Our Rating: 87/100

Few brands in the market offer the reliability and quality that Kenwood brings to the table. It is a highly acclaimed brand and the KAC-M3004 4 channel digital amplifier proves why that is so. 

The 4-channel amp may not pack the kind of power you find in other models in our review, but its performance certainly delivers a rich sound quality. 

The Design

The KAC-M3004 impresses in a classy design featuring a brushed aluminum finish. It is fairly compact with dimensions of 6.5 x 1.75 x 3.9”, allowing you to install it almost anywhere inside the car, including the glove compartment. 

With solid hardware used in its construction, this amp is designed for long-term functionality. Everything from the printed circuitry, the chassis, and the connectors are built using high-grade material. 

The Performance

Although it comes in a relatively tiny package, the KAC-M3004 punches above its weight class with the kind of performance it delivers. It can take your car sound to the next level.

The 4 channel amp boasts a frequency response that handles the entire audible spectrum (20Hz to 20kHz). This makes sure that the highs, lows, as well as mid-range sounds in your music are enhanced, resulting in well-balanced and high-fidelity sound. 

This is not the most powerful amp out there. Its maximum power of 300W might underwhelm some people but it will still upgrade your sound. As such, it is a great choice for speakers with low sensitivity if you want to get really loud sound out of them. 

The Class D amp is rated at 50 watts x 4 at 4 Ohms or 75 watts x 4 at 2 Ohms. However, it can also be bridged into a 2-channel amp with a 150 watts rms x 2 at 4 Ohms, which I feel will be good for most high-powered subs. 

The conformal coating does a great job of protecting the amp. It is a type of polymeric film that is both water-resistant and dust-proof, which makes it an invaluable asset to have when venturing into rough and dusty off-road trails once in a while. 

 The high-level inputs used on this amplifier allow for easy installation while KAC-M3004 accepts a signal from almost any source. Whether you are using the speaker wires of your factory radio or the RCA cables of an aftermarket receiver, the speaker will function without fuss. 

When using speaker-level inputs, the amp senses the signal and turns on automatically, meaning you don’t require a remote to turn your car audio on. Additionally, high and low-pass filters on the M3004 enable you to program the cut-off frequency anywhere from 50-200Hz. 

Alternatively, you can decide to cut it off at either a lower or higher mark. If your car doesn’t have a sub and your speakers keep on rattling when handling sub-bass sounds, I suggest setting the high-pass filter in the 60Hz range to eliminate the excess distortion. 


  • Compact for convenient installation
  • Conformal-coated circuit board
  • High- and low-pass filters
  • Brush aluminum finish looks cute
  • Crisp and clear audio
  • Durable build


  • Not a good fit for big subs
  • Not very powerful
Alpine MRV-F300 4-Channel Car Amplifier
Our Rating:84/100

The Alpine MRV-F300 is another great pick from Alpine that will improve your car's audio quality! It is one of the most compact amplifiers you’ll come across on the market and despite its diminutive size, it has impressive specs to deliver a better performance than much bigger models out there. 

In short, it is a tiny yet very capable 4 channel car amplifier that can take your car audio from mediocre to magnificent. 

The Design

The Alpine MRV-F300 4 channel amp is a nicely designed and compact unit. It comes housed in a subtle brushed metal chassis that looks and feels solid. Weighing just under 2kg, this is a relatively lightweight amp, especially when you compare it to other amps in the market with a similar power rating. 

The amp measures 7 7/8″ x 6.5″ x 2 3/16″; it is very small, which allows you to squeeze it into spaces other amps wouldn’t fit. You can put it under the car seat and there will still be enough room left for speaker crossovers. 

The manufacturer uses SMT (Surface-mount Component Technology) to reduce the size of the package without compromising its audio capabilities. The workmanship on the MRV-F300 is quite impressive. You won’t find any misaligned parts like in some cheaper brands. 

It also features high-quality connectors and hex-keyed screws are used to hold the wiring securely in place. Furthermore, the connectors are labeled, ensuring there’s no guesswork if you choose to bridge the amp for more power. 

 A blue light is placed at the top of the unit, which glows when you power on the amplifier. Finally, the package comes with an Alpine Verification Certificate that explains the operation and performance of the product. 

The Performance

The sound quality is satisfying; exactly what you’d expect from a renowned brand like Alpine. The audio is clear and full, with the highs crisp and the bass hits hard with a positive impact on the overall sound. In summary, the audio reproduction is full-range and excellent, which isn’t something that can be said for all Class D amps on sale. 

This amplifier is rated at 50W x 4 RMS at 4 Ohms and 75 watts rms x 4 at 2 Ohms. It can also be bridged into 150W x 2 at 4 Ohms. 

With a frequency range of 50-400 Hz, the Alpine MRV-F300 is a nice choice for woofers or subwoofers. Furthermore, it boasts an excellent THD (Total Harmonic Distortion) that can get to as low as 0.03%, depending on your configuration. 

Considering that the amp employs Class D circuitry, you won’t have a problem with power consumption or the amp overheating. What might worry you is the background noise, which is fairly noticeable at 81dB. 

Overall, the Alpine MRV-F300 results in a powerful sound quality upgrade that will boost your driving experience. 


  • High efficiency
  • Attractive finishing
  • Compact and lightweight
  • Excellent sound quality for Class D amplifier
  • Bass boost switch
  • End caps for clean installation
  • Flexible built-in crossovers


  • No remote knob
  • Background noise
BOSS Audio R3004
Our Rating: 82/100

This is a great option for those who want to squeeze their budget as far as possible when buying a 4 channel car amp without necessarily overlooking the quality on offer. The R1004 4 channel car amplifier from BOSS audio systems is very linear and manages to produce audio with limited distortion.

Being a Class B amp, you won’t be disappointed by its power output and it will come in handy when you want to boost the juice in your car door speakers.

The Design

The Boss Riot series R1004 is a compact amplifier measuring 7.8 x 9 x 2”. It also weighs a mere 1.4kg, which makes it easy during installation especially when you consider that package includes mounting hardware, as well as an instructional manual.

The amplifier is housed in a sleek black anodized aluminum frame. A back-lit illuminated Boss logo in the middle of the top chassis glows in a cool blue when the unit is powered to complement the stealth black of the housing. 

Thanks to a built-in thermal protection feature on the R1004, you can enjoy good music on prolonged rides without the risk of the amplifier overheating. You also get conformal-coating on the PCB to offer layers of protection from water and dust. 

The Performance

The Boss Riot series offers enough power to upgrade your dash, door, or deck speakers. It comes with a peak power of 400W and is rated at 100W x 4 at 2 Ohms or 50W x 4 at 4 Ohms. However, it is not bridgeable and has to be used as a 4-channel amp.

The frequency response is 12 to 22000Hz while the Total Harmonic Distortion is 0,01%. Thanks to the Class A/B circuitry that the Riot series uses, it can produce great sound quality while offering more power efficiency with minimal sound distortion.

Furthermore, the amp is 2-ohm stable to produce more power, hence more volume. It can effortlessly power speakers or subs with all the 4 channels being used at 2 Ohms. 

You can rest assured that the amplifier is self-monitoring for safety anytime it is running. This is thanks to the built-in thermal protection, which automatically turns the amp on or off to prevent system overheating and consequent damage. 

In the event there is an electrical short, this feature will cut off the power until the issue is remedied. 

The R1004 also comes with Switchable Input Sensitivity, a feature that allows you the freedom to connect the amp with whichever standard source unit you can access. Its flexibility of use is enhanced by the inclusion of both high and low-level inputs.

This lets you create a customized audio system using just about any factory OEM or aftermarket source unit. The high-level inputs will pick the signal from the speaker whereas the low-level inputs will accept the signal from pre-amp outputs of the source unit. 

Another extra feature you get on the BOSS Audio Systems R1004 is the variable gain control, which will provide you with a clean input signal with both stock or aftermarket stereo systems. Overall, this is a great bargain considering the features you get and the performance it offers. 


  • 2-Ohm stable
  • Switchable Input Sensitivity
  • Minimal distortion
  • Extremely cheap
  • Clean and clear sound
  • MOSFET power supply
  • Durable anodized aluminum chassis
  • Protection circuits to prevent system overheating


  • Not bridgeable
  • May shut down for a short while when cooling
Rockford Fosgate P600X4 Punch 600 Watt 4 Channel Car Amplifier
Our Rating: 85/100

Although Rockford may not be considered to have the same legacy as Kenwood or Alpine, it is still a well-known brand in the automotive audio industry with a fair share of great products under its belt.

A good example is the Rockford Fosgate P6OOX4! With this 4 channel amp, the company went the extra mile to produce a unit that can take your listening experience to a whole new level. 

The Design

The Rockford Fosgate P600X4 is one of the best 4 channel amps around when it comes to looks. It features a nice black chassis with straight edges. It is a durably constructed unit with dimensions of 2.38” x 7.76” x 13.28". This puts it in the bigger range of amps on the market while its 5kg weight means you’ll some bit of work to do during installation. 

This 4 channel car amplifier employs a Dynamic Thermal Management system, which utilizes forced air to spread heat evenly across the amplifier, as well as through the high-mass heatsink. As a result, heat is efficiently drawn from the internal components. 

This is paired with a proprietary MEHSA cooling process that maximizes the transfer of heat from the MOSFET power supply to the heatsink, enabling heat to escape much faster so that transistors stay cooler for better functioning.

The Performance

The Rockford Fosgate P600x4 is the ideal option to use on a full-range system. The Class A/B 4-channel amplifier can, however, be used for a 3-way system with a front stage that features a sub on the backchannel. Overall, it is a nice way to inject some fun into your driving sessions, especially on those long and boring trips. 

With its multi-channel design, the Rockford Fosgate amplifier can power pretty much any stereo system configuration. It is rated at 75W x 4 at 4 Ohms or 150W x 4 at 2 Ohms. Alternatively, it can be bridged into a 2-channel unit offering 300W x 2 at 4 Ohms.

This should be enough power to turn heads when you cruise around the neighborhood. I like the RCA inputs used on the amp, which come with the ability to accept high, as well as low-level sound signals without requiring any kind of signal converter. 

The signal to noise ratio on the amp is above average at 150/85dB, depending on your system setup. Meanwhile, the unit can handle a frequency range of between 20Hz and 20kHz. Thanks to C.L.E.A.N technology (Calibrated Level Eliminates Audible Noise), the amplifier produces music that is as powerful as it is seamless. 

This setup allows you to set your amp to match the receiver’s output. This means when the receiver gets to maximum volume, the 4 channel amp also supplies the speakers with maximum clean power. Additionally, there is little background noise to deal with, even at quiet listening levels. 

Generally, the controls on the Rockford Fosgate P600X4 are easy to use and these include input levels on the front and rear end of the amp, a built-in crossover, as well as Punch EQ circuits for precise tuning of the bass frequencies.

You also get a line-level output and punch level control to allow for flexibility as the system grows while maintaining the Y-adapters at a minimum.


  • High S/N ratio
  • 150W per channel at 2 Ohms
  • Short circuit and overcurrent protection
  • Cast aluminum heatsink
  • MOSFET power supply
  • C.L.E.A.N setup


  • Slightly expensive
Pioneer GM-A5702-2-
Our Rating: 84/100

The Pioneer GM-A6704 4-channel amp comes with all it takes to improve your music listening experience while driving. From dramatic design to dramatic sound distinction, this amp will have you looking forward to your next road trip. 

It allows you to enjoy high-fidelity audio when you turn the volume of the system to override the noise on the road. 

The Design

This amp stands out from the rest with its one-of-a-kind construction. It boasts a chilled-out design that intricately blends the colors red and black with a recognizable “Pioneer” logo sitting pretty on the top chassis. 

Measuring 4.1 x 8.5 x 2.4, the amplifier is conveniently compact and features a slim floor-standing design that you can effortlessly fit in many corners inside your car during mounting. It also weighs just over 2 pounds, making for a lightweight and easy to handle car accessory. 

The Performance

The Pioneer GM-A6704 is a powerful amplifier that will push the limits of functionality and flexibility of your car stereo system. It delivers a maximum of 1000W of maximum power and is rated at 60W x 4 at 4 Ohms or 95W x 4 at 2 Ohms. Furthermore, it is bridgeable to 190W x 2 at 4 Ohms. 

Several specs help to enhance the practicality of using this amp. For instance, it features a variable high pass filter that allows for adjustable sound frequency between 40Hz and 500Hz, as well as improved car stereo system flexibility depending on the characteristics of the sub and user preference. 

A bass boost in the GM-A6704 can be programmed to variable levels between 0-12dB for optimal bass reproduction. This simple yet crucial control adds to the overall balance of sound while also impacting the listening experience and genre of music being played. 

The Class A/B amp handles frequencies between 10Hz and 70kHz with a low Total Harmonic Distortion of only 0.05%. Meanwhile, the signal to noise ratio is 95dB. 

This new brand of pioneer speakers does a great job of offering a higher-power performance compared to previous models despite its shrinking size. 

Another great feature about this amp is that it will automatically choose the right input signal mode; speaker level inputs or RCA. Once you turn on the receiver, the amp also turns on automatically, and when linked to an OEM receiver or one without RCA output, the device automatically picks up the input to power up in tandem with the receiver. 

In short, Pioneer amps generally sense the input signal automatically and select speaker level inputs or RCA level mode for simplified operation. On the downside, there is a noticeable noise from the 4 channel amp when it's running. 


  • Easy to install
  • Compact floor-standing design
  • Little to no sound distortion
  • Bass boost
  • Automatically picks input signal
  • Pretty powerful
  • Good value for money


  • Slightly expensive


Is a 4-Channel Amp Worth it?

Definitely! Adding an amp to your car stereo system will allow you to enjoy louder and clearer music. The amp in your car head unit is not usually the best. Even if it’s rated 50x 4 like the amp you want to install, you’ll be lucky to get 25RMS from each channel. 

A 4-channels amp is the best option if you want to inject more power into your front and rear door car speakers. With each speaker getting a dedicated channel, you will get to experience rear-fill sound quality in your car that enhances your driving experiences. 

What is a 4-Channel Car Amplifier?

A 4 channel amp is a device that receives an electrical signal from your car’s head unit, amplifies it, before sending it to the speakers in your car stereo system. 4-channel car amps are used to distribute an equal amount of power to all four of your front and rear car door speakers. 

However, they can also be used to power two car speakers and a sub. Overall, they improve the sound quality inside your car and make the journey more exciting. 

How Many Speakers Can I put on a 4-Channel amp?

With a 4 channel amp, each channel can serve one car speaker, meaning you can use it on four speakers. Alternatively, the amp can be bridged so that two channels end up serving one speaker (usually a subwoofer) to supply more power, meaning you can connect two or three speakers to your 4 channel amp. 

Finally, with appropriate wiring, an amp can let you connect two speakers to one channel, ensuring that you put up to eight speakers on your 4-channel amp. This typically applies when the 4 channel amp comes with a 2-ohm setting since the amplifier gives out two times the usual RMS. 

After it's all said and done, we recommend:

Alpine X-A70F X-Series 4/3/2 Channel Power Density Amplifier
our score

Why it is better?

  • Class D amp
  • 90+% efficiency
  • 0.05% Total Harmonic Distortion
  • 120W rms x 4 at 4 Ohms or 175W rms x 4 at 2 Ohms
  • 106dB signal to noise ratio
  • Variable low and high pass filters
  • Bass EQ
  • Continuous thermal control


Selecting an amplifier to install inside your car can be challenging , but with the right guidance, you will select the right amplifier to breathe new life into your car audio system. The best 4 channel car amps we have reviewed above offer a great starting point when you want to inject more power into car speakers. 

Select the one that appeals to your budget and your preferences to make sure those long road trips are no longer boring! 

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