The Best Monoblock Amplifier for a Car

The Best Monoblock Amplifier for a Car

Like everything in the audio industry, getting the best monoblock amplifier (subwoofer amplifier) for your car takes a bit of research, because it’s not just about getting the most powerful amp you can.

Of course, the purpose of an amplifier is to make your music loud and clear, and the more power your amplifier outputs, the louder your music will get. But it’s important not to overdo it. There’s a limit to how much power subwoofer can handle, and if you cross the limit you could seriously damage them.

Everything needs to be matched with your amplifier and subwoofer, and if you’d like to learn about that or even make sure you know exactly what a monoblock amp is before reading the review, you can jump the Buyer’s Guide which is further down the page.

For those of you that want to get straight to the review, let’s take a look at the best Monoblock Amplifiers on the market.

In this review, I have tried to be as diverse as possible. There are better monoblocks that I haven’t included, because I wanted to be varied in price as well as quality.

The good thing about a monoblock amplifier is that they’re relatively cheap anyway. Sure, some are very expensive, but compared with 4-channel or 5-channel amps, they’re much cheaper.

So without further ado, let’s get into the review…

The Best Monoblock Amplifiers

Rockford Fosgate P500X1BD Punch – Efficient Subwoofer Amplifier

Rockford Fosgate P500X1BD Punch 500 Watt Class-bd Mono Amplifier

Starting with one of the most recognized names in the car audio industry Rockford Fosgate, and this Class B/D P500X1BD Punch subwoofer amplifier continues its tradition of delivering quality products.

This powerful amplifier utilizes both B and D classes making the quality and efficiency second to none in the monoblock amp category.

The amplifier can produce 150W RMS @ 4 Ohms, or 300W RMS into a 2-Ohm load, and is stable down to 1 Ohm, where it can produce a powerful 500W RMS.

The RCA inputs of this amp can accept both Hi or Low level audio signals without the need of a signal converter, and variable Low Pass Filter 12 dB/Oct Butterworth crossovers ensures the amp is more efficient in driving the right noises to your subwoofer.

The monoblock features an Infrasonic Filter 28Hz @ 12dB/Octave, which improves performance and power handling by eliminates really frequencies that are potentially damaging to your subwoofer, and require a lot of power to produce.

Added Rockford Fosgate’s Punch EQ2 Bass: 0dB to +18dB @ 45Hz, and this amplifier gives some serious power with arguably the most efficiency.

The mono amplifier is made with Rockford’s custom heat sink design that uses high aluminum mass, which maximizes heat transfer from the output MOSFETS to the surrounding air. This helps keep the circuitry  cool even under high power and output demand.

The THD from 4 Ohms down to 1 Ohm is <1%, which is pretty standard for a good quality amplifier. That said, the Signal to Noise Ratio (S/N)  is a very impressive 100dB.

This amplifier is the most efficient monoblock on the market. It’s not cheap, but if you can afford to buy it, you will have a very powerful and effective amplifier for many years.

Rockford Fosgate P500X1BD Punch 500 Watt Class-bd Mono Amplifier

Class B/D
Power @ 4 Ohm – 150W RMS
Power @ 2 Ohm – 300W RMS
Power @ 1 Ohm – 500W RMS
Frequency Response (Hz): – 20-250 Hz
On-board Punch EQ with +18dB boost @ 45Hz.
Low-Pass Crossover Frequency: 50 – 250 Hz
Subsonic Filter: Switchable Off/28 Hz
Bass Boost: 0 – 18 dB
12dB/octave Butterworth crossover
Features C.L.E.A.N. Set-up
MOSFET power supply
Cast Aluminum Heatsink
Total Harmonic Distortion: <1.0%
Signal-to-Noise Ratio S/N: 100 dB
Recommended Fuse: 80A

Kicker CXA800.1 – Monoblock Amp Stable @ 1 Ohm

Kicker 46CXA8001 subwoofer amplifier

Another well known name in the car audio industry: Kicker produces quality product after quality product, and this CX Series Monoblock Class-D Subwoofer Amplifier is a beast.

The amplifier is stable down to 1 Ohm impedance, where you’ll be able to push some power to your subwoofer motor at 800W RMS. At 2 Ohms it can manage 600W while at 4 Ohms, you’ll be able to push 300W RMS. All very powerful, and will add much energy to your soundscape.

Anyone who likes bass, and who doesn’t who wants a monoblock amp, will love Kicker’s KickEQ™ 6dB variable bass boost which ensures more car shaking boom at lower frequencies.

Added with the 12 dB crossover and the 24 dB subsonic filter and this amplifier allows you to easily sculpt the sound you want.

The amp features a low pass: 50 – 200 Hz, 12 dB/octave, which adds to the quality of the bass, and the low and high level inputs ensures this amplifier performs excellently on a wide range of frequencies.

As well as being economical on power thanks to it being Class D, the subsonic filter also helps filter out any unheard low frequencies that your subwoofer makes. This helps with the efficiency of the amp and also protects your subwoofer from possible damage.

The S/N is an impressive >95 dB while the THD is a bit standard 1% from 1-4 Ohms.

Kicker’s CX-Series amplifier technology is well-known for being powerful throughout the car audio industry, and this subwoofer amplifier gives you the power and flexibility to run some powerful subs and drive some car shaking bass.

Kicker 46CXA8001 very powerful monoblock amp

Class D
Power @ 4 Ohm – 300W RMS
Power @ 2 Ohm – 600W RMS
Power @ 1 Ohm – 800W RMS
Frequency Response (Hz): – 20-200 Hz
KickEQ™ 6dB variable bass boost
Speaker-level (high-level) inputs
FIT+™ (Fail-safe Integration Technology-PLUS) means it works with nearly every radio
Low level Input Sensitivity: 250mV-10V
High level Input Sensitivity: 1V-40V
Variable low-pass filter: 50 – 200 Hz, 12 dB/octave
Subsonic filter: 25 Hz , 24 dB/octave
Variable Bass Boost: 0 to +6 dB bass boost at 40 Hz
Total Harmonic Distortion THD: 1.0%
Signal-to-Noise Ratio S/N: >95 dB
Recommended Fuse: N/A

Taramps BASS 3K – Mono Amplifier For Extreme Power And Bass

The next amplifier on my list comes from Taramps, the Brazilian car audio company well-known for making quality amplifiers.

And this BASS 3K product is their most powerful subwoofer amplifier yet. It’s stable at 1 or 2 Ohms, and the 3000W it produces at 1 Ohm can’t be beaten for this price entry. Even at 2 Ohms you can push and incredible 1920 RMS which is easily enough for two powerful subwoofers.

And all that power is needed to push some low frequencies which is an impressive 8 Hz to 250 Hz, and the amp’s customized adjustments allows you to sculpt the sound needed according to the size of your car.

If that isn’t enough, it benefits from a variable bass boost and a subsonic filter, which allows your subwoofers to perform to their peak, while the high and low pass crossovers helps you sculpt the perfect bass with little distortion even at high volumes.

With the signal to noise ratio an impressive > 95db, it makes one wonder why anyone would choose anything else when shopping for a subwoofer amp. If it’s powerful bass at extreme volume you’re after noting beats this amplifier at the price entry.

Taramps BASS 3K 1 Ohm 3000 Watts Class D Mono Amplifier terminals

Class D
Power @ 2 Ohm – 1920W RMS
Power @ 1 Ohm – 3000W RMS
Input Sensitivity: 220Mhz
Frequency Response: 8Hz to 250Hz (-3Db)
Crossover High Pass (Hpf): Variable, 8 A 30Hz (-12Db / 8th)
Crossover Low Pass (Lpf): Variable, 55 A 250Hz (-12Db / 8th)
Bass Boost: Parametric, 35 – 60Hz, 0 ~ + 10Db
Signal to Noise Ratio:> 95dB
Total Harmonic Distortion THD: N/A
Recommended Fuse: N/A

Rockville dBM12 – Powerful, Marine Subwoofer Amplifier

Rockville DBM12 2000W 2 Ohm Marine/Boat Monoblock Amplifier

Rockville have upgraded its popular dB car amplifiers, adding marine grade parts to deliver this powerful marine standard monoblock amp.

The dBM12 features a Maxi fuse with a rating of 60 Amps, which allows this amp to put out 500W RMS @ 2 Ohms, or 300W @ 4 Ohms, both of which is conservative according to the manufacturer’s website.

The marine amp’s frequency response is 15 Hz – 250 Hz, which will allow your subwoofer to take control of the powerful lows. Added with the amp’s fully adjustable 12dB/Octave crossover allows you to sculpt more bass with less harmonic distortion.

If that’s not enough, the amp’s Low Pass Filter from 50 Hz – 250 Hz, and a subsonic filter from 15 Hz – 55 Hz, makes for the harmony to be driven to your subwoofer more efficiently.

This is helped with the High-Speed MOSFET Power Supply, and the aluminum heat sink which helps the efficiency of the Class D amplifier, which is perfect for those who spend time out in the oceans.

With all the external parts rustproof including the aluminum base, and all the circuitry conformal coated with waterproof glue, and waterproof silicone covering the terminals it ensures the amplifier will not be damaged by moisture.

All the features ensures the monoblock amplifier’s THD is an impressive <0.1% , while the S/N Ratio is over >90 dB.

Rockville isn’t the first brand that comes to mind when talking amplifiers, but with this dBM12 pushes out some serios power, which the company claims the be ‘the best sounding out of any series we have ever created.’

Rockville DBM12 2000W 2 Ohm Marine/Boat Mono Amplifier

Class D
Power @ 4 Ohm: 300W
Power @ 2 Ohm: 500W
Frequency Response: 15Hz – 250Hz
Fully Adjustable 12dB / Octave Crossover with Differential Circuitry
Adjustable Low Pass Filter: 50Hz – 250Hz
Adjustable Subsonic Filter: 15Hz – 55Hz
Adjustable Input Level Control
Fully Adjustable 12dB Bass Equalizer
Painted Conformal Coating PCB Board (Uses 2577 Waterproof Glue)
Waterproof silicone covers for end panels
Rustproof Aluminum heatsink with white painted finish
Stainless steel end panels are rustproof
All screws and mounting hardware are stainless steel and rustproof
Bottom panel is aluminum and rustproof
High-Speed MOSFET Power Supply
Signal to Noise Ratio S/N: >90 dB
Total Harmonic Distortion THD: <0.1%
Recommended Fuse: 60A

BOSS Audio OX1.5KM – Budget Monblock Amp

BOSS Audio OX1.5KM Monoblock Car Amplifier

BOSS Audio is well-known for its budget audio equipment and thi OX1.5KM subwoofer amplifier is definitely worth considering if you want to spend less than $100.

The A/B Class amplifier might not be the most powerful on my list, but at the price entry 563W RMS @ 4 Ohms isn’t bad. It’s also stable down to 2 Ohms, where it will push 1125W RMS.

This is in part thanks to the A/B Class technology, which increases the power of any amplifier compared with D Class, while also helping the sound quality that will power your subwoofer.

Because of the A/B technology used, it might eat more power than all the D Class mono amps on my list, but this amp does benefit from MOSFET power supply, which helps with the efficiency.

The car amplifier features both high-level and low-level inputs, which is pretty standard in modern monoblock amps, but makes for a more secure connection and will help the amp run more effectively.

The Variable Low Pass Filter allows you to control the power that goes into your subwoofer, while the Bass Boost allows you to boost the low bass to +18db.

And with the Variable Input Control giving you more control of the amplifier/head unit input/output signals, it means you’ll be able achieve optimum performance, and with it more control over the sound you want to sculpt.

There are some complaints from buyers in the reviews, because the amplifier claims to be 5000W Max power, but you should never look towards the max power on any audio equipment.

I can’t find anything about the S/N or THD on the specifications, which is never a good sign, but for the price entry you’re not going to get all the bells and whistles. This single channel amp is decent and it will drive a powerful subwoofer and make a huge difference to your drives.

BOSS Audio OX1.5KM Subwoofer Car Amplifier

Class A/B
Power @ 4 Ohm: Up to 563W RMS
Power @ 2 Ohm: Up to 1125W RMS
MOSFET Power Supply
High and Low Level Inputs
Variable Low Pass Crossover
Switchable Bass Boost: 0 or 18 dB
Low Pass Filter: 50 Hz to 250 Hz
Remote Subwoofer Control Included
Signal to Noise Ratio S/N: N/A
Total Harmonic Distortion THD: N/A
Recommended Fuse: N/A

Audiobank P3001 – Cheap Subwoofer Amplifier

Audiobank P3001 – Very Cheap Subwoofer Amplifier

A lesser-known brand in the car audio space, Audiobank provides my next monoblock amp, and it’s the cheapest amp on my list, too.

Selling at under $80, this A/B Class amplifier isn’t the most powerful, so I wouldn’t recommend it if you want to run 2 subwoofers, as anything this cheap won’t last if you max it out.

It’s not easy to get the full specifications of this amp, which isn’t a good sign. Like most brands it promotes its Max Power, which is 3000W, but as already stated, ignore this.

The RMS is 550W @ 4 Ohms, but even though it’s stable down to 2 Oms, I couldn’t find any specs for its RMS power at 2 Ohms, which is never a good sign.

That said it has many of the features the more expensive amplifiers have including a Subsonic Filter which makes the amp more effective, and a Bass Boost that will make life easier when you’re trying to create the perfect sound for yourself.

Sure enough, you get these ion the other amps on my list, but the cost is a fair bit higher, and although this amp lacks in quality components that questions its capabilities, it’s still decent for the price entry.

At this price, you can’t really expect the most powerful and long lasting amplifier, but if you’re budgeting you will get a decent subwoofer amp that will make a difference to your soundscape.

Audiobank P3001 – Very Cheap Single Channel Amplifier

Class A/B
Power @ 4 Ohm: Up to 550W RMS
Power @ 2 Ohm: N/A
High Pass Crossover: 80Hz-4kHz
Subsonic Filter
Bass Boost
Thermal and Speaker Short Protection Circuitry
Continuously Variable Input Gain Control
LED Power and Protection Indicators
Signal to Noise Ratio: N/A
Total Harmonic Distortion THD: N/A
Recommended Fuse: N/A

PIONEER GM-D9701 – Compact Monoblock Amp


The Pioneer GM-D9701 Mono Class D amplifier is quite simply a compact, versatile beast. It’s one of the more expensive amplifiers on my list, but if you can afford north of $250, it’s well worth it.

At 50% smaller than Pioneer’s A/B amplifiers, this amp is perfect for anyone who wants crisp and powerful energy but limited for space.

The Class D monoblock amp is stable down to 1 Ohm, where it will push out a staggering 1200W RMS. This will allow you to run 2 very powerful subwoofers and give you earth shaking bass.

At 2 Ohms, you can push a not too shabby 800W RMS, while at 4 Ohms it will power 500W quite comfortably.

At 10 Hz – 240 Hz, the Frequency Response is lower than most monoblock amps on my list. And with a variable LPF – adjustable from 40 Hz to 240 Hz, and a wired bass boost remote control, it makes it easier to sculpt the bass you desire and help your subwoofers produce more resounding lows.

It’s always a good sign when the specs show the THD and S/N, and Pioneer proudly states that this amp’s THD <0.05%, while the S/N is a mind blowing >100 dB.

This is a very compact and powerful car mono amplifier, and even though it’s slightly above the average price, if you can afford it, you will not regret it.

It will allow you to push two powerful subwoofers and energize your soundscape with crisp and punchy bass, and also turn a few heads as you drive down the mainstreet.

PIONEER 2400W MONOCLASS D Monoblock (GM-D9701)

Class D
Power @ 4 Ohm: 500W RMS
Power @ 2 Ohm: 800W RMS
Power @ 1 Ohm: 1200W RMS
Pulse Width Modulated MOSFET power supply
Wired remote bass level control included
Frequency response: 10-240 Hz
Variable Bass Boost (0 to +12 dB bass boost at 50 Hz)
Variable low-pass filter (40-240 Hz, 24 dB/octave)
Preamp RCA outputs to daisy chain multiple amps
3-way protection circuitry (thermal, overload, and speaker short protection)
Heavy duty aluminum alloy heat-sink for extreme heat dissipation
Nickel-plated RCA level inputs
Nickel-plated screw terminals
CEA-2006 compliant amplifier
Signal to Noise Ratio: >100dB
Total Harmonic Distortion THD: <0.05%
Recommended Fuse: 40A x 3

Alpine S-A60M S-Series – Powerful, Compact and Versatile Mono Amplifier

Alpine S-A60M S-Series - Powerful, Compact and Versatile Mono Amplifier

Alpine has made some high quality audio products over time, and this S-A60M S-Series compact, mono amplifier really packs a punch.

Stable at 2 Ohms this monoblock will deliver up to 600W RMS to your subwoofer, or 2, and of course at 4 Ohms it will push 330W RMS, guaranteeing some powerful bass while out in your car.

Its power makes it suitable for any size vehicle, and its compactness less than 8×8 inches and just over 2 inches in depth makes it perfect for a small car where space is of a premium.

Compact amplifiers are usually installed in tight places, which means they’re prone to getting hot. And while most amps feature heat reducing technology or shutdown protection if it gets hot, this Alpine Mono Amplifier excels in that department.

If this amp begins to get too hot, the Enhanced Shutdown Performance technology doesn’t shut down the amp to protect it. Instead it rolls back the output a bit which helps it cool down whole allowing you to listen to your music still.

The amp also includes preamp- and speaker-level inputs, making it a match for pretty much any vehicle installation, even one with a factory radio.

The frequency response is 10 Hz – 400 Hz, and the amp benefits from a low-pass filter (50-400 Hz, 24 dB/octave) and a variable bass boost (0-12 dB at 50 Hz), which makes it easier to control the frequencies that reach your subwoofers.

The THD into 4 Ohms is <0.03%, while at 2 Ohms it’s <0.05%. And the S/N Ratio is >85%, which is very good, but pretty standard for the price range.

All in, the quality of this Alpine amp makes it perfect for any vehicle, especially if you have a smaller car. But that’s not because it lacks power, it’s because its compact, and it packs a punch in any sized vehicle.

Alpine S-A60M S-Series - Powerful, Compact and Versatile Mono Amplifier

Class D
Power @ 4 Ohm: 330W RMS
Power @ 2 Ohm: 600W RMS
Frequency Response: 10HZ-400Hz (+/- 3 dB)
Damping Factor: > 1000
Crossover: Variable HPF/LPF (50-400 Hz, 24 dB/octave)
Variable bass boost (0-12 dB at 50 Hz)
Speaker-level inputs (Speaker Wire to RCA Adapter Required)
Improved heat sink and protection circuit design that eliminates thermal shut-down, for dependable music playback
Remote Sensing automatic turn-on when using speaker-level inputs
Signal to Noise Ratio: >85dB
Total Harmonic Distortion THD: <0.03%
Recommended Fuse: 30A x 2

DS18 CANDY-XXL1B – Compact Subwoofer Amplifier

DS18 CANDY-XXL1B – Compact Subwoofer Amplifier That Packs A Punch

There are a few mono amplifiers on my list that are compact, but none more so than the Candy-XXL1B from DS18. This deceiving little bugger is only 11×5 inches and less than 2 inches in depth, making it perfect for pretty much anywhere, including a motorbike.

DS18 are known for making high quality audio equipment and this D Class monoblock maintains the brand’s tradition.

Stable from 4 Ohms down to 1 Ohm, the amplifier pushes some impressive continuous power, allowing you to run one or two powerful subwoofers with ease.

DS18 claims their amplifiers give audiophiles ‘goosebumps when they turn up their amplifiers,’ making the listener’s ‘ears tingle with pleasure’ when utilizing them to their potential.

And this Candy series monoblock at 4 Ohms gives you 400W RMS, while 2 Ohms will give you 650W RMS, and if you really want the power the amplifier is stable down to 1 Ohm where it will push an impressive 1000W RMS.

The amp comes with all the features you’d expect such as a Low Pass Filter (50Hz – 150Hz), and there’s also a Bass Boost (0dB-+12dB) that gives you more control over the bass you want for your specific taste.

The THD is a staggering 0.0001%, while the Signal-to-Noise Ratio is >100 dB, which means you will get crystal clear bass at pumping volumes with this little beast.

This product is on the higher side of my price entries, but it’s seriously a high quality amplifier, and the sound quality and clarity is incredible. It’s is perfect for anyone who wants a small audio footprint while having all the benefits of a bigger amplifier.

DS18 CANDY-XXL1B – Compact Subwoofer Amplifier That Packs A Punch

Class D
Power @ 4 Ohm: 400W RMS
Power @ 2 Ohm: 650W RMS
Power @ 1 Ohm: 1000W RMS
Frequency Response: 20Hz – 20KHz
Input Sensitivity: 0.2V-+6V
Low Pass Filter: 50Hz – 150Hz
Bass Boost: 0dB-+12dB
Signal-to-Noise Ratio: 100dB
Total Harmonic Distortion THD: <0.0001%
Recommended Fuse: 35A x 3

MTX Audio Terminator TNP212DV – All-In-One Monoblock Amplifier With Dual 12-Inch Subwoofers

MTX Audio Terminator TNP212DV – All-In-One Monoblock Amplifier With Dual 12-Inch Subwoofers – A Perfect Starter Kit

If you’re in the market for a full sub set up, this MTX Audio Terminator mono amplifier and x2 12-inch subwoofers in a vented enclosure is absolutely perfect.

The TNA500D amplifier is stable at 2 Ohms and can push 500W RMS giving you enough power to run your dual subs as both subwoofers are wired internally at 2 Ohms and can handle 500W RMS each.

The amplifier benefits from all the features you’d expect from a modern Class D Subwoofer Amplifier, such as a Low Pass Filter and a Subsonic Filter which makes it easier for your subwoofers to drive the sounds with more clarity.

The S/N is pretty standard at 80dB, but the power this amplifier drives and the sound the dual 12 inch subs make is impressive.

The subwoofer enclosure is made using extra-strength 5/8 inch MDF, ensuring it can handle the massive low frequency sound waves generated by the subwoofers without problem.

The enclosure is also wrapped in a black aircraft grade carpet meaning it’s resilient to wear and tear, and the design goes well with pretty much any interior.

Of course, being an all-in-one package it’s all designed to work harmoniously together, and that it does. Yes, you’re limited because it’s a package, but for a starter kit I highly recommend it.

Installation is as easy as you can get, and you don’t have to worry about matching everything else up. There are no speaker wires, however, so make sure you get the correct amp wiring kit.

MTX Audio Terminator TNP212DV – All-In-One Monoblock Amplifier With Dual 12-Inch Subwoofers – A Perfect Starter Kit

The included 500-watt RMS class D amplifier delivers ideal power to the enclosure
Dual 12 inch vented subwoofer enclosure designed for use in almost any vehicle
The enclosure is constructed using 5/8″ MDF and aviation Carpet for durable and long lasting performance
Add a source and wires and you have the perfect subwoofer starter kit
Subwoofer: 500W RMS Each @ 2 Ohm
Amplifier: 1000W RMS @ 2 Ohm

Buyer’s Guide

Getting a monoblock amplifier for your car means you want some powerful bass for your drive. But it’s not just about splashing ut the most and getting what looks to be the most powerful car amp on the market.

And finding the best subwoofer amplifier is different for different people, so you need to make sure you get the right one to suit your needs.

You need to familiarize yourself with important technical specification that comes with all amplifiers, namely Power Output (RMS), Impedance (Ohms), and Sensitivity.

If you can match this with your subwoofers, you will definitely be in for a treat when you install your new car audio equipment.

What Are Monoblock Amplifiers?

Monoblock Amps are beasts that have a few varied names, depending on the person. Some people call them monoblocks, subwoofer amplifiers, mono amplifiers and even single-channel amps. They’re all the same thing, but the name varies depending on who you talk to.

As you might sense from the word, Mono means one. Mono Car Amplifiers are used to provide the power signals to a single channel mostly. They are ideal for powerful low frequencies, because when the power demand increases they stabilize the electric current resistance.

Most monoblocks are Class D technology, although some are A/B. Both technologies are the most common in all amplifiers with different amount of channekls, because of the versatility and efficiency A/B and D classes produce.

Most subwoofer amplifiers will need 4 gauge AWG wire, but always check your manufacturer to be sure. Some will come with the wires included, but if not you should make sure you purchase a good quality amp wiring kit.

Most subwoofer amps are either 4 or 2 Ohms impedance, but many are also stable down to 1 Ohm. The lower the impedance the more power you will be able to push, so if you intend to run 2 powerful subwoofers you will likely need something that is stable down to 1 Ohm and can push some power.

Whenever you go shopping for a car amp, therefore, you need to make sure it can handle the Power Output and Impedance your subwoofers demand.

Amplifier Class

Amplifiers belong to different classes with the most popular ones being A, B, A/B and D. The biggest difference between them is efficiency. All of the above and most subwoofer amplifiers use either D or A/B class.

A/B is a uses the best of both A and B classes, and is a very common technology used. However, D Class is the most common technology used in subwoofer amplifiers. Here is a brief explanation of both A/B and D Class.

A/B Class

A/B Class is a hybrid of both A and B classes. They use the best of both worlds but there are trade offs, too. A Class is known for being a purer signal, but are less efficient, whereas, B class are very efficient.

Class AB amplifiers are a little bit less efficient than that of Class B amplifiers, but much more than A. You can also switch between A and B if you prefer or keep it in A/B mode.

A/B benefits from the purity of the signal A class is known for and amplifiers using A/B technology produce the best bass with least distortion.

D Class

D Class technology is much more efficient (90-95% efficiency) than even B Class, and they need less power to run.

This is thanks to the amplifier actually being off when switched off, which isn’t the case with other Classes. This means the output transistors will not retaining any electricity, which ensures the amp uses less power and remains cooler.

They’re known for having better bass control too, which is another reason most subwoofer amps use D Class.

Should I Get A/B or D Class?

Should you get an A/B or D Class amplifier? Well, like most things in the car audio world it’s down to personal choice.

efficiency of Class D and AB Class for amplifier

D Class have a bad reputation, which is quickly eradicating, because of their first lot of amps created more distortion than A/B, but as the technology has evolved, D Class is starting to become the most popular choice.

For me, especially with a monoblock amp, I would get a D Class amp as they’re way more efficient tahn any other class, and the sound fidelity is getting much better with modern amps.

That’s not to say A/B mono amplifiers should be ignored. Of course these are getting more efficient as the technology evolves, and the clarity of sound is better. So, it’s really a case of what you prefer.

Power Rating

The purpose of an amplifier is to make music loud, but you should never overdo it because there’s a limit to what your speakers can handle, so don’t just go for the most powerful amp you see.

When manufacturers specify the power, for example 5000W Max Power, it’s not worth paying attention to. That’s because Max Power is a misguided specification that some manufacturers use to make their product sound more powerful.

It’s all about the RMS Power, which is the continuous power your amp can produce for lengthy periods of time, and not the sudden bursts the Max Power represents.

You should match the RMS of your subwoofer to that of your mon amplifier from a minimum 75% of your amp’s RMS up to 150% of it.

An overpowered subwoofer is better than an underpowered one, and don’t forget that if you run 2 subs with a mono amp, you should add the total RMS of both and match them to the car amplifier you intend to purchase.


Impedance measures the internal resistance found in the amplifier’s circuit. The greater the impedance, the lower the amount of current that an amplifier can supply at any one time.

Low impedance generally puts less stress on the amplifier and allows it to push more RMS power. Most monoblock amps are optimized for 2 Ohms, although many are stable at 4, 2 and 1 Ohm.

A subwoofer has impedance, too, and this is basically the load that the amplifier will push. Most amplifiers are set to an impedance of 4 Ohms although most will allow you to switch to a lower setting.

Before you do, however, make sure that your subwoofer can handle the larger influx of power, because if the impedance is too low, the amplifier may supply more power than what the subwoofer can handle, possibly causing permanent damage.

Tune Your Amp for the Best Possible Sound

As well as all the features, it’s important to tune your car amp properly. There are a few ways to do this, but basically you should set the gains so your amplifier aligns with your receiver. Once the amp gains is set, you should look to set the crossover frequency correctly, and only when these dials are set correctly can you get the very best out of your monoblock.

Getting The Best Mono Amplifier Need Not Be Overwhelming

As with everything in the car audio industry, much of it is down to personal preference. Sure, there are better and worse quality products, but spending more doesn’t guarantee a better sound.

Amplifiers are a great way to enhance your listening experience, but as good as every amp in my review is, they’re not flawless, and they all have pros and cons. Ensuring you set the gain control and crossover filters correctly is as important as the quality of the amp it’self.

You need to understand what it is that suits you. Efficiency, size, and power are the three main things to consider, but you also want to look into ease of installation and running it.

Whichever amp you choose for your subwoofers, I’m sure you will improve the soundscape no end. Just don’t expect thanks from your neighbors.

Subwoofer Amplifiers FAQs

Can you bridge a Mono Amp?

Bridging an amplifier involves consolidating the power of multiple channels into one, and because sub amps only have 1 channel, they’re not bridgeable. Some can be strapped, however, which means they can be linked up with another amplifier, giving you more opportunity to push more power.

Can a Monoblock Amp power 2 subs?

Yes, they’re well-suited to power two subwoofers. To do this, you can either wire them parallel circuit or a series circuit, but it’s easier and better to wire a parallel circuit.
To run 2 subwoofers from your monoblock in a parallel circuit, your Impedance of Subwoofers will be divided in 2, so if you have a 2 Ohm Monoblock, you’ll be able to run 2 x 4 Ohm Subwoofers.
To wire in a parallel circuit, you need to connect 2 sets of red wires into the (+) terminals on the amplifier, and one end each of the other red wires should go into a subwoofer (+) terminal.
Then, connect two sets of black negative speaker wires into the (-) terminal on the amp, and attach one end of each into the subwoofer (-) terminal each.
For a series circuit, instead of dividing the Impedance by 2 you multiply it by two, to match the Impedance of your amp and subwoofers. So, if you have a 2 Ohm Monoblock, you would have to run 2 x 1 Ohm subwoofers.
To wire a series circuit, one length of black wire will run from the (-) output terminal in the amplifier to the (-) terminal in the subwoofer. Another speaker wire will connect the 2 subwoofers from (-) to (+).
Then run a red wire from the other (=) terminal on the subwoofer to the Mono Amplifier (-) terminal.series vs parallel wiring for impedance in a monoblock to 2 subwoofers

What gauge wire should I use for a Subwoofer?

16-gauge wire works good enough most of the time, but if your subwoofer has an RMS of more than 1000W then you should maybe go as big as 12 gauge. For more information on speaker wire sizes check this article out: Car Audio Speaker Wire Gauge Guide

Is a subwoofer amp better than a 2-Channel Amp?

It’s a common question, but it’s all down to personal preference, and what you need. 2-Channel amps are better at 2 Ohms per channel, whereas a mono amplifier performs better at 1 Ohm. You really have to decide how much power you need, especially if you’re running two subwoofers.

Do you need an Amp for a Subwoofer?

Subwoofers do work without an amplifier, because a sub already has amplifiers installed in it. However, anyone who wants a subwoofer tends to like their bass loud and clear, and the in-built amps in a subwoofer aren’t good enough to get the potential out.

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