Searching for the Best Car Amplifier?

Best Car Amplifier

Whether you’re looking for sound quality, high output or budget friendly choices, I will break down the options and show you the best car amplifier for your needs.

Estimated read time: 4 minutes 30 seconds.  Want to read later?

Car amplifiers can generally be broken down into 3 categories:

  • Mono or single channel amplifiers – used for subwoofers
  • 4 channel amplifiers – used for interior speakers
  • 5 channel amplifiers – used for a combination of interior speakers and subwoofers

When shopping for the best car amplifier, it is important to pay attention to the following specifications:

  • RMS power ratings
  • Total Harmonic Distortion level or THD

All the amplifiers I recommend here are excellent quality.  You will see they have relatively low total harmonic distortion level, typically less than or equal to 1%.  They’re also rather efficient and come in a compact size.  I’ve also listed physical dimensions for your reference as well.

Check your specs

Note, all of the amplifiers I recommend follow CEA-2006 Compliance regarding RMS rating guidelines:

  • Number of Watts X Number Channels RMS @ Number of ohms at 14.4 volts

Make it a point to look at an amplifier’s RMS power rating and see at what impedance or ohms it is rated at.  Some less than stellar car amplifier companies out there will advertise an unrealistic power handling rating just to grab your attention.  Oftentimes it’s only when you look at the owner’s manual do you find these ratings are listed at an unrealistic impedance such as .5 or 1 ohms.

For interior speaker amplifiers, generally speaking, you’re always going to be running the amp at 4 ohms.  For subwoofers, you want your final impedance to stay in the range of 2 to 4 ohms.  Anything less than 2 ohms is typically too little resistance for an amplifier to handle effectively.  When you run a car amplifier below the specified impedance capability, you risk both sound quality and damage to your amp.

So pay close attention to those RMS ratings when shopping for an amplifier.  For reference, RMS stands for Root Mean Square.  Simply put, it is an approximation of continuous average power.

Power vs Size vs Sound Quality vs Budget

For this post, I’ve included a basic $ rating system in the amplifier comparison charts to give you an idea of cost against power, overall size and sound quality.  Here is the key for that simple rating system:

  • $ = $75 – $150
  • $$ = $150 – $250
  • $$$ = $250 – $400
  • $$$$ = $400 & up

Best Mono Car Amplifiers

In the mono amp category, the more popular amps are in the 500 watt power handling range.  In our shop we sell both the JL Audio JX 500/1D and the Alpine MRV-M500.  Either amp is a great choice when you need a 500 watt mono car amplifier.  If you are also installing the optional bass knob, JL Audio’s RBC-1 is slightly easier and cleaner to install.  It’s slightly smaller so it’s easier to dismantle and mount in a stealth manner than Alpine’s RUX-KNOB.

If you need something slightly more powerful, like in the 600 watt range, I recommend the JL Audio XD 600/1 v2.  It’s a great compact little amplifier that is very efficient and reliable.  For a 1000 watt RMS mono amplifier, consider the JL Audio JX 1000/1D.  The JL Audio JX 1000/1D puts out 1000 watts RMS at 2 ohms, but only 500 watts RMS at 4 ohms.  Alpine’s PDX-M12 on the other hand has a regulated power supply and will consistently put out 1200 watts RMS whether you have a 2 ohm, 3 ohm or 4 ohm load.  If you need a high output mono amplifier with a small footprint, the Alpine PDX-M12 is the way to go.

 Best Car Amplifier – Mono up to 500 watts RMS

 
Best car amplifier - MRVM500
Alpine MRV-M500
Best Car Amplifier - JX 500/1D
JL Audio - JX 500/1D
RMS @ 2 ohms at 14.4 Volts500 watts500 watts
RMS @ 4 ohms at 14.4 Volts300 watts300 watts
Bass Knob ReadyYes - RUX-KNOBYes - RBC-1
THD<1%<1%
Physical Size L x W x H7-7/8'' x 7-7/8'' x 2-3/16''7-11/16" x 7-13/16" x 2-1/8"
Gauge Power Wire RecommendedMinimum 8 GaugeMinimum 8 Gauge
Price$$$

Best Car Amplifier – Mono up to 1200 watts RMS

 
Best Car Amplifier - JL Audio XD600/1v2
JL Audio XD600/1v2
Best Car Amplifier - JL Audio JX 1000/1D
JL Audio JX 1000/1D
Best Car Amplifier - PDX-M12
Alpine PDX-M12
RMS @ 2 ohms at 14.4 Volts600 watts1000 watts1200 watts
RMS @ 4 ohms at 14.4 Volts400 watts500 watts1200 watts
Bass Knob ReadyYes - HD-RLCYes - RBC-1Yes - RUX-KNOB
THD<1%<1%<1%
Physical Size L x W x H8-1/2'' x 7-1/8'' x 2-1/16''10-15/16" x 7-11/16" x 2-1/16" 10-1/8'' x 7-9/16'' x 2''
Gauge Power Wire RecommendedMinimum 4 GaugeMinimum 4 GaugeMinimum 4 Gauge
Price$$$$$$$$$

4 Channel Amplifiers

When shopping for a 4 channel amp, keep in mind, there is actually a sound quality difference between amplifiers.  Take these three amps for example:

All of these amps are great options with various power handling ranges.  They’re all compact and efficient.  The KTP-445U is the most compact and efficient of all.  Aside from power output and physical size, there is also an audible sound quality difference between all of these amps.

If you were to compare the KTP-445U to the built in amplifier of an Alpine head unit (about 18 watts x 4 RMS) you would notice a considerable difference in output, clarity and vibrancy.  Yet, when compared to the JL XD 400/4 v2 amplifier, the Alpine KTP-445U sounds rather flat.  If you had the opportunity to listen to these car amplifiers on a sound board (like I do) you would notice the XD 400/4 v2 sounds more lively and vibrant.  If you then compared the JL XD 400/4 v2 amplifier to the Alpine PDX-F4 amplifier you would find the PDX-F4 is even more vibrant and has greater detail and subtle nuance.

Best Car Amplifier – 4 Channel

 
Best Car Amplifier - KTP-445U
Alpine KTP-445U
Best Car Amplifier - JL Audio XD400/4 v2
JL Audio XD400/4 v2
Best Car Amplifier - Alpine PDX-F4
Alpine PDX-F4
RMS @ 2 ohms at 14.4 Volts90 x 2 (bridged to 4 ohm load per channel)200 x 2 (bridged to 4 ohm load per channel)200 x 2 (bridged to 4 ohm load per channel)
RMS @ 4 ohms at 14.4 Volts45 Watts x 475 Watts x 4100 Watts X 4
Sound Quality Rating6/108/109/10
THD<.03%<1%<1%
Physical Size L x W x H7-7/16'' x 1-1/2'' x 2-1/12''8-9/16" x 7-1/8" x 2-1/16" 10-1/8'' x 7-9/16'' x 2''
Gauge Power Wire RecommendedMinimum 18 GaugeMinimum 8 GaugeMinimum 4 Gauge
Price$$$$$$$$

5 Channel Car Amplifiers

5 Channel car amplifiers are a convenient option for anyone looking for a space saving, total system amplifier.  In my shop, we sell both Kenwood and Alpine 5 channel amplifiers.  The major differences between these 5 channel car amplifiers is their power capabilities and overall size.  They all have great sound quality and provide warm, rich and natural tonal qualities.  The Kenwood has a very small footprint along with pretty impressive power output – note there is no optional plug in bass knob for the Kenwood.  If you purchased this amplifier, you could always install a universal bass knob, like the PAC Audio LC1.  That’s what we do in our shop when we sell and install this amplifier.

Best Car Amplifier – 5 Channel

 
Best Car Amplifier - Alpine MRX-V70
Alpine MRX-V70
Best Car Amplifier - Kenwood Excelon XR900/5
Kenwood Excelon XR900/5
Best Car Amplifier - Alpine PDX-V9
Alpine PDX-V9
RMS @ 2 ohms at 14.4 Volts90 watts x 4 + 350 watts x 1 into 2 Ohms75 watts x 4 + 600 watts x 1100 watts X 4 plus 500 watts x 1
RMS @ 4 ohms at 14.4 Volts60 watts x 4 + 250 watts x 1 into 4 Ohms60 watts x 4 + 400 watts x 1100 Watts X 4 plus 500 watts x 1
Bass Knob ReadyYes - RUX-KNOBNoYes - RUX-KNOB
Sound Quality Rating7/108/109/10
THD<1%<1%<1%
Physical Size L x W x H10-5/8'' x 9'' x 2-1/4"10-1/4" x 6-5/8" x 2"10-1/8'' x 7-1/2'' x 2"
Gauge Power Wire RecommendedMinimum 8 GaugeMinimum 4 GaugeMinimum 4 Gauge
Price$$$$$$$$$$

Conclusion

As you can see, there are a variety of choices and options out there when shopping for the best car amplifier.  Space constraints, desired RMS power output, sound quality and budget can all factor into your decision making process when selecting the best car amplifier.  I hope this post has made it a little easier to select the best car amplifier for your unique needs and vehicle application.

Still confused about the best car amplifier for your needs?  Feel free to post a question in the comments and I’d be happy to clarify any details and answer any questions.  Thanks for reading!

What it means to bridge a car stereo amp

What happens to a 2 channel amp when you bridge it?  Does it change the impedance?

Estimated read time: 6 minutes 42 seconds.  Want to read later?

Yes and no.  It doesn’t change the impedance of the speakers you are using, but it does change the impedance that the amplifier itself sees.  That’s why you will find multiple ratings on 2 channel amps as there are a few different ways you can run them and one of the more popular ways to run them is bridged.  Bridged is a way of mixing both left and right stereo signals from a 2 channel amp.  It allows you to run a mono signal.  This is great if you plan on using your two channel amp for a sub or subs.  How do you make sense of the ratings?  Here’s a run down of the typical types of ratings you will see:

X amount RMS power x 2 @ 4 ohms defines using a 2 channel amp to run a pair of full range car audio speakers

Higher X amount of RMS power x 2 @ 2 ohms is the other rating you will see.  This is like running two subs that have an impedance of 2 ohms each with one sub on the left channel and one on the right channel.

The last rating you will often see is the combined total of the last rating or Higher X amount of RMS power (combined) x 1 @ 4 ohms.

I’ve been inspired to write this post after receiving an unsettling email from a fellow reader.  He has a high powered 2 channel amp that puts out either:

150 x 2 @ 4 ohms
300 x 2 @ 2 ohms
600 x 1 @ 4 ohms

His understanding, as well as my understanding, is this:  The last rating is obviously a bridged rating.  To bridge a 2 channel amp, you typically  use the left positive terminal on the amp and right negative terminal on the amp.  See picture below:

To bridge a 2 channel amp you usually need to use the left positive and right negative on the amp terminals.

Some manufacturers do it a little differently so pay attention to the installation manual.  Note this Audison amp doesn’t use the outside terminals, but it is still using left positive and right negative for bridging:

Audison 2 channel amp show bridged.

The trick with bridging a 2 channel amp is to remember that the amp will always split and share that impedance between the two channels.  In other words, if you bridge a 2 channel amp to a 4 ohm load, the amp sees 1/2 that load or a 2 ohm load per channel.  You never want to bridge an amp with an impedance less than 4 ohms.  Given this information, it’s safe to assume that the reader’s amp will put out 600 watts RMS when bridged to a 4 ohm load.  These two ratings are essentially telling us the same thing:

300 x 2 @ 2 ohms

600 x 1 @ 4 ohms

In this particular instance, the reader is looking at purchasing two subwoofers.  The subs are offered in either single voice coil 4 ohm or single voice coil 2 ohm.  Well, we know that when we parallel two 4 ohm subs we get a 2 ohm load and if we series two 4 ohm subs we get an 8 ohm load.  So we can conclude the single voice coil 4 ohm subs would not be the right impedance to buy.

We know that if we parallel two 2 ohm subs we would get a 1 ohm load and if we series two 2 ohm subs we would get a 4 ohm load.  1 ohm isn’t going to work, but 4 ohm will.  So in this situation, the correct answer would be to buy two of the single voice coil 2 ohm subs, wire them in series, then bridge the amp.  The amp would put out 600 watts RMS when bridged to the 4 ohm load.

After contacting the manufacturer of the subs, the reader received the wrong information.  The manufacturer’s tech support disagreed and adamantly argued that he should buy the two single voice coil 4 ohm subs and series those to an 8 ohm load.  He feverishly argued that whenever you bridge an amp it sees half the impedance.

This is true.  The amp would technically see 4 ohms.  But at 4 ohms, the amp only puts out 300 watts RMS, do you agree?

Here are those ratings again:

  • 150 x 2 @ 4 ohms    – What we would get if we were to run two 4 ohm subs to each channel of the amp
  • 300 x 2 @ 2 ohms –  What we would get if we were to run two 2 ohm subs to each channel of the amp
  • 600 x 1 @ 4 ohms –  What we would get if we were to bridge the amp and give it a 4 ohm load

I consulted with another technician at the manufacturer as I was distraught that such a reputable, long time standing company was giving out such misguided direction.  I began to think I was losing my mind when the second technician sided with both of us saying we were both right.  How could we both be right?  The amp cannot produce the same 600 watts RMS when bridged to either a 4 ohm or an 8 ohm load.  If we understand anything about resistance and amplifiers we know that output varies with resistance.

Unless, of course, your company primarily produces amplifiers with regulated power supply’s.  An amplifier with a regulated power supply will put out the same amount of power regardless of whether you give it 2 ohms, 3 ohms or 4 ohms.  But this, my friends, is not a regulated power supply amp.  It’s not a class D mono amp.  It’s an old school, class A, high powered, two channel amp and that beast needs a 4 ohm load when bridged to supply you with 600 watts of raw power, damn it.

Even though I’ve been doing this for more than 10 years and have sold more than my fair share of bridged amp setups, I actually started to doubt my understanding when I encountered two manufacturer technicians that believed otherwise.  I consulted with my hubby on this one (who has more than 30 years experience in this industry).  So here is our conclusion to help YOU, the almighty consumer, navigate the numerous power ratings on amplifiers.

  • When you bridge a 2 channel amp (or the rear channels of a 4 channel amp) the amp sees 1/2 that impedance
  • Amplifier company’s will provide several different power ratings to help you understand the various capabilities of the amp
  • X amount of power RMS x 2 @ 4 ohms means this is what the amp will put out if you hook up two 4 ohm speakers or subs, one speaker or sub to the left channel and one speaker or sub to the right channel.  The amp will play a stereo signal in this scenario.
  • X amount of power RMS x 2 @ 2 ohms means this is what the amp will put out if you hook up two 2 ohm speakers or subs, one speaker or sub to the left channel and one speaker or sub to the right channel.  The amp will play a stereo signal in this scenario.
  • X amount of power RMS x 1 @ 4 ohms means this is what the amp will put out if you bridge the amp to a final 4 ohm load.  It doesn’t matter if it’s one speaker or two speakers as long as the final impedance at the speaker wire going into the amp is 4 ohms.  The amp will play a mixed stereo or mono signal in this scenario.

Let’s take a look at this screen shot from JL Audio:

Various different ratings on a 2 channel as described by the manufacturer.

We can conclude from these ratings that this amp will do the following:

  • If you hook up two full range 4 ohm car audio speakers to each channel (left and right), the amp would supply you with 110 watts RMS from each channel.
  • If you were to hook up two 2 ohm subwoofers (or two full range 2 ohm car audio speakers) to each channel (left and right), the amp would supply you with 180 watts RMS from each channel.
  • If you were to hook up one single voice coil 4 ohm subwoofer and bridge the amp, the amp would supply you with 360 watts RMS total to the one subwoofer.

This last rating demonstrates bridging the amp.  The amp is essentially seeing half that final load when bridged.  We are mixing left and right stereo and combining both channels to basically create a mono amp.  You can see by the ratings that the amp is obviously seeing 2 ohms per channel as the total RMS output at 4 ohms bridged equals that of the two channels run separately with a 2 ohm load on each.

I sincerely hope that helps to clear up confusion regarding what happens to an amp when bridged and what kind of impedance you can give an amp that is being bridged.  As a rule of thumb, never bridge an amp with anything less than a 4 ohm load.  It will be unstable and heat up and shut down on you.

This experience has taught me there’s even more misinformation out there than I otherwise thought. Do you guys agree with me?  Disagree with me?  I’d love to know.  I really hope this helps everyone out there who plans on bridging their 2 channel or 4 channel amp.

What is HP Filter, LP Filter? What do crossovers do?


Hey guys! I decided to do another video for you to explain what crossovers are and how they should be set in your car audio system. I also decided to clean off the dresser behind me in the video, because I think I looked like such a slob in the last one! Anyways, chores aside, let’s talk about crossovers. On many of the newer head units these days, if you scan through the audio settings you will see things like HP filter, LP filter and when you select them a few options for frequencies to select from. You may also see these settings on your amp and not really know what they do.

In the simplest way to describe this, crossovers are frequency filters. They allow us to filter out certain frequencies to certain speakers. So on your interior speakers, that would be your HP or High Pass Filter. High Pass means we’re only allowing the higher frequencies to play through, so this is what you want to adjust for your interior speakers. LP or Low Pass means we’re only allowing lower frequencies to play through. So ideally you want your interior speakers playing what they’re best designed to play, about 60-80 hertz and up and we have our subs playing about 60-80 hertz and down. The important thing to remember is you don’t want any gaps between these frequency settings as then you’ve cut them out of your stereo system all together. So make sure the cut off is about the same on both your low pass and your high pass filter.


The other important thing to remember is you never want to use both the crossover setting built into your head unit AND the crossover setting on your amp. Use one or the other. So never use the LP filter on your head unit and the LP filter on your subwoofer amp, that can cause weird phasing issues. Same thing on the interiors, if you’re using a 4 channel amp, either use the HP filter on the amp or the HP filter on the head unit, but don’t use both.

I hope this helps clarify what crossovers are, how they work and what they can do for your car audio system. If you have questions about where you should have your crossovers set at, just please comment and I’ll respond and help you out. Also, if you guys like what you see here, please submit this site to one of the social networking links, I would really appreciate the support. Thanks for stopping by and checking out the site!