I enjoy listening to music a lot while I drive to and from work. However, my commute takes me through a particularly busy part of the city, which means that my speakers always have to compete with road noise.
In addition, my car is relatively noisy too. Both these factors made for a not-so-optimal listening experience until I finally caved and got myself an excellent Class D amplifier earlier this year.
Recently I’ve had a friend ask me what’s the best car amplifier to get this year and so I did my usual run of product testing.
I gathered about 15 different amplifiers from all classes and spent a couple of days with each.
I then managed to pick out a top-five based on my experiences. You can read my review of each below:
- Kenwood KAC-M3004: The Best Overall Car Amplifier
- Car Amplifiers 101
- The Top Five Picks
- Frequently Asked Questions
Kenwood KAC-M3004: The Best Overall Car Amplifier
If I had to choose my absolute favorite amp from the top five choices, I’d have to go with the Kenwood KAC-M3004. Here are my reasons:
- First of all, it’s a Class D amplifier which means it needs to be very efficient and won’t overheat with prolonged use. 50 watts RMS is more than enough to blast my music to and from work every day.
- In addition to this, filters were an extremely nice touch, allowing me to cut off any white noise from the sub-bass and upper-bass regions.
Car Amplifiers 101
Before I get to the rest of the reviews, I want to talk a little bit about car amplifiers, specifically what you need to consider before getting one.
Usually, we skim over the technical specifications but they’re important to know!
Specs such as power output and frequency response will let you know for certain whether a particular amplifier is compatible with your current speaker setup before you waste your money on a hunch.
Other not-so-technical factors can matter too, and in this section, I’m going to be detailing everything you need to know:
The Different Classes
There are four popular car amplifier classes: Class A, B, AB and D. The differentiating factor between these classes is efficiency.
In the context of amplifiers, efficiency is a measure of how much Alternative Current (AC) the unit can deliver while consuming the absolute minimum amount of Direct Current (DC).
The efficiency varies greatly between the classes because of how their circuits are set up:
Class A amplifiers contain the simplest circuit which has them conducting electricity 100% of the time. There are two main drawbacks to this.
First of all, the amplifier can heat up relatively quickly and secondly, efficiency is the lowest among all the amplifiers (just 30%).
Just because there is a lot of electricity available at all times doesn’t mean that all of it is going to be used up. Your speakers will draw what they need and the remainder will be eventually converted to heat energy.
However, Class A amplifiers have the purest signal path, meaning they provide the best audio quality.
Unlike Class A, Class B amplifiers conduct electricity about 50% of the time.
This reduces the amount of wasted electricity, resulting in them being 40% more power efficient when compared to Class A amplifiers.
However, this setup leads to a reduction in signal purity causing a tiny amount of distortion.
Class AB circuits are a sort of hybrid of Class A and Class B circuits. They have biasing diodes in the Class B chain which helps cancel out the aforementioned distortion you can expect from B circuits.
As a result, you get the best of both worlds: the efficiency of Class B amplifiers coupled with the audio quality of Class A units.
Class D amplifiers can reach efficiencies of up to 95%. One of the main reasons for this is that when the amplifier is turned off, the output transistors don’t hold back any electricity.
As a result, none is converted to heat. However, Class D amplifiers offer significantly less signal purity than Class A or Class B amplifiers.
4 Factors To Consider When Purchasing An Amplifier
Here are the most important things you need to look at when shopping for a new car amplifier:
The whole point of buying an amplifier is to make things louder than what your car stereo can achieve on its own.
Hence, this means that an amplifier should be able to supply your speakers with way more power, driving up the amount of decibels (volume) that is being output.
However, the issue is that speakers aren’t able to absorb an infinite amount of power; they have limits.
Cross this limit and the excess electricity will be converted to heat energy which could, in turn, cause the speaker to fry.
Fortunately, there are two technical specs that let you know what a speaker’s limit is: the Maximum RMS and Peak Power.
Maximum RMS tells you the maximum amount of watts a speaker can handle on a regular basis.
Peak power is a measure of the absolute maximum amount of power you can supply at once to the speaker without damaging it.
Think of the latter metric as a ‘point of no return’. It’s sort of like when you go beyond the point of elasticity in a stretchy material and it gets permanently deformed.
Amplifiers also have RMS and peak power ratings but they indicate power output instead of handling. Hence, before buying an amplifier, make sure its power output ratings are compatible with your speaker’s power handling specs.
High-powered amplifiers should only be hooked up to speakers with a high RMS. Otherwise, you may end up damaging the latter each time you try to pump up the volume.
In addition to your speaker’s power handling, you should also pay attention to its sensitivity.
A speaker’s sensitivity rating tells you how loud it can get (in decibels) when just one watt of power supplied to it.
If a speaker has a sensitivity rating of 85dB for example, that means it’ll get moderately loud with one watt. With each additional watt, you increase the volume by 3dB.
Hence, the more sensitive your speaker is the less power you’ll need to get it loud.
This tells you the range of frequencies that an amplifier can handle. In music, frequencies can span between 20 Hz to 20,000 Hz – at least that’s all we can hear.
If you want to be able to hear every detail properly in the amplified signal, make sure your amplifier’s frequency response is capable of handling this range.
Some amplifiers can only handle the bass frequency range, which spans from 20 Hz to 250 Hz.
These units are designed to work with subwoofers only. Therefore you should always pay strict attention to the frequency response before you buy an amplifier.
The number of channels you need in amplifier will depend on the type and number of speakers you’ve got in your set up.
Let’s say you’ve got two stereo-compatible speakers mounted on either side of your car. In that case, a stereo dual-channel amplifier would complement this set up best.
Stereo channels transmit either the left or right signal separately which means that the original panning of the instruments in the music will be more accurately replicated.
On the other hand, mono channels transmit both right and left signals together. If you’ve only got one speaker, then a mono one channel amplifier is the way to go.
Some amplifiers have a dedicated mono channel for a subwoofer which allows you to manage its levels independently.
When you’re buying an amplifier it’s also best to consider what additions you might make to your set up in the future.
If you plan on buying a couple of more speakers, make sure you have the extra amount of channels to accommodate them.
Amplifiers can vary greatly in size from one make or model to the other.
Ideally, you should go for more compact amplifiers since it gives you more flexibility in terms of where to store it.
If the amplifier is quite bulky then the only place for it will be the trunk of your car.
The Top Five Picks
Now that you’re well informed on the different classes of amplifiers and what to consider before you buy one, let’s take a look at my top five picks for this year:
Rockford Fosgate R500x1d (Class D)
- 300 Watts x 1 @ 4-Ohms, 500 Watts x 1 @ 2-Ohms, Frequency 20Hz to...
- Onboard 12dB/octave LP/HP/AP crossover & Infrasonic filter. Power Wire...
- On-board Punch EQ with +18dB boost at 45Hz. Input Sensitivity: 150 mV...
- Cast Aluminum Heatsink with Stealth top mounted control panel
- Includes wired remote (Punch Level Control). High efficiency amplifier...
Made for Subwoofers
The R500X1D has a frequency response of 20Hz to 250Hz which means it’s meant to handle just the bass range.
In addition, since it was made to work with just subwoofers, the R500X1D is appropriately a one-channel mono amplifier.
500 Watts RMS
With the ability to output 500 watts of power on a regular basis, the Rockford Fosgate R500X1D was designed to be paired with subwoofers that have high power-handling ratings.
500 watts is actually pretty overkill for most people but if you like blasting music on a daily basis, then this amplifier might suit you well.
Variable Low-Pass Filter
When you pass an audio signal through a low-pass filter, it sets a cut off frequency. The frequencies higher than the cut-off value are blocked while those below it are allowed to pass.
Low-pass filters are very useful for cutting out distortion or white noise from the upper-bass frequencies.
Rockford Fosgate R500X1D comes with a variable low-pass filter which means you can set the cut off at different frequencies between 50 Hz to 250 Hz.
This allowed me to really hone the output from my subwoofer, cutting out any high-pitched fizzing which would otherwise drown out some of the details in the bass.
The R500X1D also features a bass boost specifically set at the 45 Hz frequency. It allows you to boost up signals at this frequency by up to 12dB.
So whenever you’re listening to electronic songs and you want to have a bigger bass attack, simply crank this up.
The R500X1D sports an aluminium chassis which serves to draw heat away from the amplifier’s internal components by absorbing it. Hence, the amplifier is much less likely to overheat even with prolonged use.
Further, the R500X1D is equipped with sensors that track both the output current and power supply temperature.
These sensors help to ensure that no heat damage is caused by dips in the amplifier’s resistance or any problems with the circuitry.
This amplifier is just 8 and a half inches in width and 2 inches in height so you could definitely fit this under the seat of your car.
- High Maximum RMS
- Comes with a variable low-pass filter for cutting out bass distortion
- Bass-boost gives the low-end more attack
- Designed to only work with subwoofers
Kenwood KAC-M3004 4 Channel (Class D)
- PEAK POWER: Max Power 600 Watts. RMS (50 Watts x 4 @ 4-Ohm or 75W x 4...
- RMS POWER: (50 Watts x 4 @ 4-Ohm or 75W x 4 @ 2-Ohm. High Quality...
- MARINE CERTIFIED: Conformal coated marine grade circuit board is great...
- FEATURES: KENWOOD Triangle Indicator Light, 3-Way Protection...
- COMPACT SIZE: Cutting Edge KENWOOD Amplifier technology allows...
Unlike the Rockford Fosgate R500X1D, the KAC-M3004 can handle all frequencies between 20 Hz to 20 kHz.
This means that it can boost everything from sub-bass to upper-treble signals found in your music.
50 Watts RMS
The KAC-M3004 has an RMS rating of 50 watts per channel. While this is much less than what the R500X1D outputs, it’s still more than enough to get to ear-splitting volumes!
Plus the reduced RMS allows the KAC-M3004 to be compatible with a wider range of car speakers.
Compatible With Subwoofers
While the amplifier doesn’t have dedicated mono channels for connecting to a subwoofer, you can actually switch it to a 2-channel mode and send 150 watts each to a pair of subs.
The conformal coating consists of a thin polymeric film that prevents water and dirt from touching the internal components of the circuit.
Hence, this amplifier is well-suited for off-roading.
Variable High And Low-Pass Filters
The KAC-M3004 comes with both a high-pass and low-pass filter that allows you to set the cut off frequency anywhere between 50-200 Hz.
A high-pass filter is very useful if your speakers aren’t the best at handle sub-bass. You can set the cut-off at around 60Hz and eliminate distortion from the really low beats.
At just around 7 inches in width, 3 inches in depth and an inch in height, this amplifier is compact enough to mount in most places.
- Wide frequency response
- High power output in each channel
- 4 channels
- Compatible with subwoofers
- The circuit is protected from water and dust
- Variable high and low-pass filters
- I really can’t think of any
Planet Audio Ac1500.1m (Class A/B)
- power: max power output of 1500 watts at 2 ohms into one channel....
- high level inputs: speaker level inputs are commonly referred to as...
- low level inputs: line level inputs, also known as rca inputs or...
- low-pass crossover: a low-pass filter is an electronic circuit that...
- variable bass boost: variable bass boost allows you to adjust the low...
Built for Subwoofers
Like the Rockford Fosgate R500X1D, the Planet Audio AC1500.1M can only handle frequencies in the low-end spectrum. Hence it was designed to work with only subwoofers.
As with all subwoofer amplifiers, you can expect a high power output from the AC1500.1M.
With 1500 watts of peak power all focused into a single channel, you’ll be able to crank up the bass to dangerously loud levels while still maintaining every bit of clarity.
High Level And Low-Level Inputs
Speaker level (high level) inputs allow you to easily connect a stereo or radio that doesn’t have RCA (low-level) outputs.
Having both types of inputs allows you to connect pretty much any stereo to this amplifier.
Variable Low-Pass filters
Just like the R500X1D and the KAC-M3004, the Planet Audio AC1500.1M also comes with a variable low-pass filter that lets you eliminate distortion in the upper-bass region.
Variable Bass Boost
The included bass boost allows you to enhance the sub-bass frequencies. This is quite handy if you’re listening to electronic music and feel that the bass could use a little more ‘oomph’.
Subwoofer Level Control
The AC1500.1M conveniently comes with a remote control that lets you manipulate the level of the subwoofer without having to mess with any dials.
This allows you to safely adjust the intensity while you’re driving.
Lastly, the AC1500.1M is designed in such a way that it automatically shuts off if the amplifier gets too hot.
This way, you don’t have to constantly worry whether you’re driving the amp too hard since it will shut off before you have a chance to damage it.
- 1500 watts peak power
- Accepts both high-level and low-level outputs
- Variable low-pass filter and bass boost
- Handy remote control for subwoofer level
- Short protection
- Can only work with subwoofers
Rockford Fosgate R300x4 4 Channel (Class A/B)
- 50 Watts x 4 @ 4-Ohm / 75 Watts x 4 @ 2-Ohm / 150 Watts x 2 @ 4-Ohm...
- Accepts High Level & RCA Level Input
- Cast aluminum heatsink with Top Mount Controls
- 12dB/octave crossover
- Class A/B Circuit Topology
The R300X4 handles all frequencies between 20Hz to 20Khz meaning it can work with any kind of speaker; not just subwoofers.
50 Watts RMS
The Rockford Fosgate R300X4 can output 50 watts RMS on each of its four channels, which is more than enough for blasting your music on a regular basis.
Compatible with Subwoofers
Just like with the Kenwood KAC-M3004, you can actually switch this 4-channel amplifier into a 2-channel mode if you need to connect to a pair of subwoofers.
In the 2-channel mode, you’re able to drive 150 watts through each channel into a subwoofer.
Variable High And Low-Pass Filters
These allowed me to eliminate any distortion from either the sub-bass or upper-bass regions by playing around with the cut-off frequency.
You can set either the high or low-pass filter to any frequency between 50-250 Hz.
Selectable Bass Boost
The bass boost is a great solution if you feel like your speaker could use some extra help with the sub-bass frequencies.
This feature allows you to push all signals at the 45Hz frequency by either 6 or 12 decibels, depending on how prominent you want those low beats to be.
With a width of 13 inches and a depth of 7, this is a relatively bulky amplifier.
Hence, your options will be a little limited when it comes to mounting it inside your car.
- Wide frequency response
- 50 watts RMS with each channel
- Compatible with subwoofers
- High and low-pass filters let you clean up the sub-bass and upper-bass frequencies
- Selectable bass boost for adding more ‘punch’ to the low-end
- It’s a bit bulky
Boss Audio Pt1000 2 Channel (Class A/B)
- POWER: 1500 Watts Max x 2 @2-Ohms, 750 Watts Max x 2 @4-Ohms, 3000...
- CLASS A/B TOPOLOGY: Class ‘A’ amplifiers have enormous amount of...
- FULL RANGE: With a Full Range amplifier you not only have the option...
- MOSFET POWER SUPPLY: A MOSFET is basically an electrical switch that...
- VARIABLE GAIN CONTROL: The gain control is not for adjusting volume....
Wide Frequency Response
The BOSS Audio PT1000’s frequency response covers any frequency from 20 Hz to 20 kHz, so you can pair it up with both speakers and subwoofers.
This Class A/B channel is capable of belting out a maximum of 500 watts through each of its channels, making it the most powerful full-range amplifier on this list.
Hence, before you buy this for your setup, make sure that your speakers can handle this much power.
Variable Gain Control
The gain control allows you to set a limit to the amount of signal that is being sent to your amplifier.
When used properly, it’ll allow you to cut out any unwanted distortion from the signal.
Variable Bass Boost
This boost works similarly to what you’ll find in the other amplifiers on this list.
It allows you to spike up the sub-bass frequencies, making for a bass sound that’s deeper and more ‘in-your-face’.
Compatible With Subwoofers
The BOSS Audio PT1000 allows you to bridge the two channels into one 1000 watt channel which you can then connect to a high-powered subwoofer.
The PT1000 measures 9.5 inches in depth and 10.31 inches in width which means that while it’s not the most compact amplifier, it’s certainly not that bulky either.
It can fit under car seats just fine. However, it does weight quite a bit at 6.62 pounds.
- Wide frequency response
- Very high-powered
- Comes with variable gain control and bass boost
- Compatible with both speakers and subwoofers
- Can’t connect to both a speaker and a subwoofer at the same time
- A bit heavy
Frequently Asked Questions
Do Amplifiers Improve Sound Quality?
Amplifiers boost audio signals so that the sound outputted will be loud enough to drown at any ambient noises.
Some amplifiers also contain additional features such as bass boosts and variable high or low-pass filters that help with tone-shaping.
What Is The Best Car Amplifier For Subwoofers?
I would highly recommend either the Rockford Fosgate R500X1D or the Planet Audio AC1500.1M for anyone with a single subwoofer.
How Do I Choose An Amp For My Subs?
Most importantly, you need to consider the number of channels, the frequency response and power output.
Amplifiers that are designed to work with subwoofers will be able to handle frequencies lower than 60 Hz.
Most subwoofer-specific amplifiers will have a single channel but often you’ll be able to bridge dual or four-channel amplifiers in order to make them work with subs. Subwoofers require more power than regular speakers, so you need to keep that in mind as well.
What Gauge Wire Should I Use For A 1000 Watt Amp?
As a general rule, if your amp’s RMS rating is between 500 to 1000, then you’ll want to use 4 gauge wiring. Anything more and you’ll need to use 2 gauge ones.
What Are Good Amplifier Brands?
Based on my personal experience, brands like Rockford Fosgate, Kenwood, Planet Audio, Pioneer and Boss Audio are among the most reliable brands when it comes to amplifiers.
The products featured on this page were last updated on 2023-05-28 at 16:39 /. Affiliate links / Images from Amazon Product Advertising API.