Hands-On Review & Test: Pioneer GM-D9605/GM-D9705 5 Channel Amplifiers

Pioneer GM-D9605 5 channel amplifier review featured image

Looking for a 5 channel car amp to drive your whole system? You’re in luck: while you’ll run across a lot of bad buys out there, there are a few that are worth the money!

In my detailed review of the Pioneer GM-D9605/GM-D9705 5 channel amplifier, I’ll show you what I found from hands-on, real-world testing and why they’re good values and great-sounding amps you’ll love.

I’m really going to dig deep so read on to learn more!

UPDATE: The GM-D9605 has been discontinued and has been replaced by the nearly identical GM-D9705, so I’ve updated my review. I’ll report my hands-on review of the GM-D9605 model as it applies to both but I’ll be sure to cover the 9705 as well where needed.

Basics first – The GM-D9605 / GM-D9705 5 channel amp explained

Pioneer GM series class D car amplifiers with GM-D9605 and GM-D9705 comparisons

The Pioneer GM line of amplifiers consists of several different power levels and channel configurations. All are class D-type amplifiers and competitively priced. (Note that the GM-Dx6xx models are now renamed the GM-Dx7xx models). The GM-D9705 is the newer version of the GM-D9605, although they’re functionally the same (aside from different looks).

The GM-D9605/GM-D9705 is one of the company’s line of midrange priced amplifiers in the Classic GM series. GM amplifiers are all class D amps, meaning they using a modern high-efficiency design based on high-speed switching amplifier technology.

Note that the 9605 and 9705 models do have some slight internal differences, however, they’re functionally the same amp and use many of the same components.

The Pioneer GM series class D car amp family

Class D amplifiers are a relatively modern approach to car audio and offer several benefits.

The biggest advantages are reduced size and cost, higher power efficiency (less power wasted as heat), and running cooler during high power output.

Much like other 5 channel amps, the GM-D9605/9705 offers flexible use that’s installation-friendly. You can run an entire great-sounding system from a single amp that can fit under a car or truck seat.

GM-D9605/9705 Amp System Options

Several configurations are possible:

  • 4 main channels (full-range front & rear) + 1 subwoofer output (bass only)
  • 3 main channels (2 standard + 1 bridged) + 1 subwoofer
  • 2 main channels (2 bridged for more power) + 1 subwoofer

In all cases, you can drive rear speakers even if you only have 1 pair of RCA outputs as a 2/4 channel input switch is provided.

It’s a great feature and saves you the cost of Y adapters and really expands your options.

Until fairly recently 5 channel amps (especially at the power level of the GM-D9605/9705) were some of the largest amps sold. They were fairly tough at times to fit into a vehicle.

Thankfully the class D design makes it possible to get the same power and flexibility in a smaller size and with less power draw, too.

Signal input options

The great news is that it’s very flexible not only in the number of channels available but it’s great for factory stereos as well.  There’s a handy 4-channel speaker level connection provided (wiring harness included).

When using a stereo without subwoofer outputs, you can use the subwoofer input switch set to “A/B” to derive low-pass bass from them instead.

Either way, it’s great for nearly any system you can dream up for your vehicle in my opinion.

Unboxing and first impressions

Pioneer GM-D9605 review unboxing front image

My Pioneer 5 channel amp (GM-D9605) arrived safe and sound. The amp is well-packaged with great foam inserts everything is nicely bagged and tucked inside. I was expecting good things from Pioneer and I’m happy to say I wasn’t disappointed!

Finally, it came! As a Pioneer car audio owner & product installer in the past, I had high expectations for the Pioneer 5 channel amp. This was a wonderful opportunity to test their modern car amp design.

My amp arrived well-packaged with a smart, professional design just like you’d expect from a leader in the car stereo industry. Right away I got a good feeling.

Everything was put together nicely and the included accessories were tucked away neatly inside.

What’s in the box?

Pioneer GM-D9605 image of included items

Pictured: Everything included with the Pioneer GM-D9605. Aside from an amp wiring kit and installation-specific accessories, you’ll have everything you need to install the amp itself and mount it. Note: I do recommend some double-sided tape for the bass remote if you’d like to avoid screw holes when mounting.

After opening up the box and removing the amp here’s what you’ll find inside:

  • Owner’s manual and warranty info
  • Bass remote knob assembly and cable (16 ft long) + mounting screws
  • Amp mounting screws, black, 1/2″
  • Speaker and power terminal Allen (hex) wrenches
  • Front/rear speaker level input harness

Note that you’ll need a good amp wiring kit like in my amp kit buying guide to make your installation easier & with great results.

It’s especially important to have good quality wire and the little bits and pieces that make the work much less of a hassle!

Pioneer GM series car amplifier high level input harness image

For factory stereos or aftermarket stereos with no RCA jacks, you’re covered! The included speaker-level (“high level”) wiring harness connects to the speaker wiring from your stereo and plugs into the amp. Industry-standard color codes are used to make wiring clear.

The included speaker level input harness is very compact and easy to understand. Not only clearly spelled out in the owner’s manual (which is very nice, by the way) but also it uses industry standard colors.

Positive and negative wiring is marked by the use of 1 striped wire for each pair of input wires for a total of 8 wires (4 inputs for both front and rear options).

For my test setup, the included hardware (screws, hex wrenches, and remote cable) worked great and I had no complaints at all.

Build quality and close-up evaluation

Pioneer GM-D9605 top view closeup image

The GM-D9605 is a great-looking amp that has a nice glossy finish on top. The sides, edges, and surrounding areas feature a lovely matte black style. Overall, it’s a great design and everything is put together nicely.

As I like to do, I gave the amp a close-up and thorough inspection to check build quality, fit and finish, and to find any defects in assembly.

I’m happy to say the build quality is great, the cosmetic looks are excellent, and I found no defects to be aware of.

I especially like how it looks on top: somewhat resembling a carbon fiber material. There’s a glossy coating over a metal pattern designed into the single-piece heavy-duty metal shell.

The amp feels great in the hand and is definitely not a lightweight by any means! When you pick up the GM-D9605, at about 7lbs in weight, you can quickly tell it’s well-made and designed for handling some big power output.

Front and rear panel details

Pioneer GM-D9605 closeup image of front and rear

Front and rear view of the amp’s controls and wiring terminals. A very compact amp for its power class at only 12.4 x 2 x 7.87″ in size, the company had to fit a lot into a small area. Controls are well laid-out and work well in my experience. The wiring terminals are interesting (I’ll cover that later) but very high-quality, too.

The front and rear panels, like other class D amplifiers, have to fit in a smaller size than the amps of days gone by. Because of this, you’ll often find similar amps have controls and labels very close together.

However, no complaints here. The crossover controls, bass remote jack, RCA input jacks, and much more are nicely done. The lithography (label printing) is nice and clear, although the topmost labels are harder to see at times.

I checked the switches and dial controls and everything felt nice and tight – no signs of cheap, low-quality parts being used.

Wiring terminals (and my thoughts on them)

Pioneer GM-D9605 wiring terminals close up image

Close up: the wiring terminals where you’ll connect power, ground, remote, and speaker wiring. They’re very high quality and offer an excellent, reliable connection as I discovered during installation. Note, however, that the openings are angled downward slightly.

Similarly, I can say the same for the wiring terminals. Unlike cheaper amps, Pioneer uses a high-quality machined metal wiring block in the design.

Within each wire terminal is a single machine screw that uses one of the 2 included hex wrenches. You’ll use the included metal wrenches to tighten down the screws and secure wiring.

Don’t sweat it, though – you can tighten them down firmly but there’s no need to get them super tight. Once tightened down firmly by hand the wire isn’t going anywhere!

A note on the terminals

There is one little detail that caught my attention, however. The wiring terminal openings are angled downward and not perfectly horizontal.

In practice, it wasn’t a problem for me, but I can see how some people might find it a bit harder to insert wiring during installation.

After installation using proper lighting (yes, I installed it outside at night!) the job went fine and I can’t really complain much.

The GM-D9605/9705 amp guts revealed! Checking out the electronics

Pioneer GM-D9605 internal components and circuit board images

To be 100% sure about the build and design quality I opened up the amp. Inside is a smartly designed, well laid-out printed circuit board (PCB) with miniaturized components and good build quality. There’s a very beefy power transformer. Components are high-quality and the assembly is well done. The 9705’s internal components are very similar as well (not shown)

I wasn’t kidding earlier when I mentioned I’d be digging deep into the details! One great way to really find out about the quality of an amp is to open it up and give it a more thorough look.

As you can see above in the images, Pioneer uses miniaturized surface mount technology (SMT) components to keep circuit space to a minimum and optimize sound quality.

Additionally, I noticed the capacitors and transformers that make up the power supply are into place for added durability and vibration resistance. That’s something you don’t always see, sadly.

It’s important to remember that the GM-D9605 & D9705 sit in a “sweet spot” in terms of cost vs quality & performance: not cheap, but not too expensive, either.

What I found inside reflects that as well: a well-made, well laid-out circuit board with good fit and great assembly quality.


Pioneer GM-D9605/D9705 Specifications
  • Channels: 5 (4 full-range + 1 subwoofer channel)
  • Amp class type: class FD (custom class D design)
  • Signal inputs: 6 RCA inputs (4 front/rear “A/B” + 2 subwoofer) + 4 ch. high-level inputs
  • 2/4 RCA input switch
  • Subwoofer: Dedicated inputs or derived from main channels
  • Bass boost level: 0 – 18dB, adjustable
  • High-level input sensing auto-on feature
  • Crossovers:
    A/B ch.: High/low pass, -12dB/Oct, 40-500Hz adjustable
    Subw.: Low pass, -12dB/-24dB/Oct selectable, 40-500Hz adjustable
    Bass boost center freq.: 50Hz
  • CEA-2006 continuous RMS power ratings:
    75W x 4 + 350W x 1 @ 4 ohms
    100W x 4 + 600W x 1 @ 2 ohms
    Bridged: 200W x 2 @ 4 ohms (Front/rear ch.)
  • Speaker terminals: Channels A, B (front, rear) stereo + single subwoofer out
  • Freq. response (A/B): 10Hz ~ 50kHz (+0dB, -3dB)
  • Freq. response (sub): 10Hz ~ 500Hz (+0dB, -3dB)
  • Total Harmonic Distortion (THD): A/B CH: <0.05% (1kHz) / SUB CH: <0.05% (100Hz)
  • Signal-to-Noise (SNR): > 94dB
  • Fuse Rating: 30A x 3
  • Includes bass remote knob + 6 wire, 6 position telephone cable
  • Includes mounting screws for amp, remote, and hex wrenches for terminals
  • Wiring terminal type: insulated high current hex screw solid block machined
  • Owner’s manual with detailed instructions
  • Protection circuit for shorts, thermal overload, low voltage
  • Warranty: 1 year
  • Size: 12.4 x 2 x 7.87 ” (31.5 x 5 x 20 cm)
  • Weight: 7lbs 2 oz (3.2kgs)

If you’re not familiar with car amplifier ratings, it’s important to understand that power ratings in the mobile electronics industry are a huge source of confusion and are often used to mislead buyers.

CEA-2006 Compliant logo

Fortunately, the industry established a good (although, voluntary) set of standards in the 2000s which reputable manufacturers use to assure you of what you’re getting. Amplifiers sold today that provide Consumer Electronics Association 2006 (CEA-2006) power specs guarantee the amp will perform as advertised.

Like several other top car audio companies, Pioneer’s GM line of amps is no different.

The GM-D9605/D9705’s CEA-2006 compliant power ratings are guaranteed correct. In fact, the GM line of amps has actually be proven to exceed their ratings by a small margin!

My hands-on experience reflects this as well. I can definitely tell you that there’s NO shortage of power with this guy!

My test setup and installation

Pioneer GM-D9605 review test setup diagram

A diagram showing the general setup used for testing the Pioneer 5 channel amplifier. I replaced my high-spec reference amplifiers and tuned my system to correct any problematic frequency response behavior in order to best test the amp’s sound performance.

Now comes the part where things get real! How would the Pioneer stand up against my class A/B reference amps that are 40% bigger in size?

And is the GM-D9605 really a great value like I thought, or a just another average, mid-tier amp?

It’s time to find out!

Installing the GM-D9605

Pioneer GM-D9605 review test amp rack image

For my test setup I at times enjoy real-world use of an amp using an amp rack and everyday listening. Here’s the Pioneer amplifier mounted on an amp rack for a reliable, neat installation.

Using the same method found in my guide on how to make your own car amp rack, I set up my test installation and installed the amp in my test car.

One thing’s for sure – if I’m going to give an amp a fair test the installation quality is definitely important. Professional installation with neat wiring and everything secured in place isn’t just good-looking but is a requirement for reliability.

Setup and wiring connections

Pioneer GM-D9605 gain setup during installation example

Getting the amp gain and crossover settings ready during installation. The controls work well and are easy to use. Additionally, what helps set the amp apart from others is how the gain level control is labeled with “Normal”, “0.5V”, and “6V”, giving you a better idea of the general range & position the dial should be at.

I set up the baseline gain, crossover, and other controls adjustments (like for the subwoofer) when mounting the amp rack into place. In my cases, the high-pass crossovers weren’t needed so I left them set to flat (off).

This allows an unrestricted audio range as my Alpine digital signal processor (DSP)/EQ already provides filtering.

For the subwoofer control, I started with an initial gain setting somewhat bit higher as from experience in my setup it’s needed. Normally I’ll fine-tailor them later once the system is powered and working ok.

Pioneer GM-D9605 wiring connection installation example

Connecting power & speaker wiring to the amp. All went well as planned, even though the downward-angled terminal openings are a bit new to me. In the end, the terminals work very well and you’ll get a nice, tight, and great-conducting connection!

Finishing it up, I wired up the amp, carefully inserting the power and speaker wiring as these types of terminals are a bit new to me. The slightly down angled openings turned out to not really be an issue at all.

They worked well, and despite the wiring openings being less visible immediately, the design is actually quite good. Using the hand wrenches supplied in the box I carefully tightened the connections to avoid stripping or any other issues.

Note: strongly recommend against using a cordless drill or screwdriver when working with terminals like this. It’s ease to overpower the screw and strip out the inset shape, leaving them rounded out and much hard to work with.

My advice is to always do delicate or fine fasteners by hand.

I also sometimes do things by hand to check the “feel” of parts – poorly designed or manufactured connections sometimes show themselves when they feel cheap or loose. That wasn’t the case here.

The connections were excellent and it only took a few moments for each connection point to get a highly secure & tight clamp.

System EQ setup

Alpine PXA-H800 DSP/EQ in-car test setup and adjustment example images

To keep things “fair” during test evaluation I made sure to remove any nasty sound peaks or dips that would give my ears a false impression about the Pioneer amp. Using my calibrated microphone and real-time analyzer (RTA) software I smoothed out any problem areas. This lets me test the amp on a “level playing field.”

Of course, it’s never a good idea to compare apples to oranges, so to speak. After installation, I used my real time analyzer (RTA) software and calibrated microphone for equalization adjustments.

This lets me do critical listening of the amp’s sound reproduction by removing any nasty peaks or dips in the sound system’s response that might influence what my ears hear.

Firing up the laptop I got to work taming any areas by adjusting my Alpine DSP/equalizer processor’s 31 bands as needed for the main channels and the subwoofer output.

More about the bass remote

Pioneer GM-D9605 bass remote installation example

The bass remote installed using double-sided tape for avoiding drill screw holes for test purposes. I do recommend the screws if you’re ok with permanent holes, but for many people using an alcohol prep pad and then sticking on adhesive tape is a great option.

The bass remote is pretty easy to install and works great, although the knob is a bit small. However, it lets you easily dial in as much slamming bass as you like with the 0-18dB boost provided.

Basically, it’s a very small assembly with a 6 pin, 6 conductor jack on the rear that installs by connecting the provided black telephone cable. At 16 ft 5″ (5m) in length, it works well in most vehicles.

Alternatively, you can also pick up a longer cable of the same type if the original isn’t long enough for you.

Close up images of Pioneer GM series car amp bass remote details

Closeup of the bass remote, a small dial control that uses a 6 pin phone cable to allow you to boost the subwoofer output’s level any time. It works great and is a really handy (and fun) way to get more enjoyment out of your music.

I especially like that it’s included at no extra charge, as some competitors charge up to $25-$30 for theirs when sold separately.

How does it sound? Real music and test tracks

Car amp test tracks playing snapshot

Some reference car audio test tracks I used for testing the amp and verifying sound quality. Top: Autosound 2000 Test CD #102. Bottom: A high-fidelity album from Mapleshade Music featuring unprocessed, excellent sound quality used in some high-end car audio demos.

Using my reference test CDs (as well as music I enjoy and I’m familiar with very well) I ran the amp through a series of tests to check some important characteristics:

  • Sound quality & clarity
  • Stereo imaging
  • Bass sound quality
  • Power output with real music

The result? The GM-D9605 had spot-on imaging in my test setup as with my class A/B reference amps. No problems there! The left, center, and right placement of the instruments was exactly spot-on.

Example of Spotify music tracks playing screenshot

Listening to everyday music like your favorite tracks on Spotify (or whatever music source you like!) is enjoyable and fun with the Pioneer. Music is crisp, clear, and can really jam hard when you crank the volume. Clear, well-recorded songs like Ne-Yo’s Miss Independent come through great and have an excellent low-end bass sound!

The music sound quality was great, with crisp, dynamic highs and punchy bass. While there is a tiny bit less detail than my original (and much less efficient) reference amplifiers, that’s to be expected of a midrange class D amp.

It’s important to understand that unless you’re spending absolute top-dollar money for a higher-end amp like the JL Audio XD700/5v2 it’s a compromise that comes with an amp in this price range.

I have to say, however, that unless you’re one of the pickiest audiophile listeners, you’ll enjoy it. It’s a very clear, musical amp that has a ton of power just waiting to perform.

Cranking up the bass anytime you like thanks to the bass remote is fun! It’s a great little feature to have and I definitely recommend installing it. The knob is a bit small so I would have liked a slightly larger size to make it even more convenient to use.

I have to say, however, that unless you’re one of the pickiest audiophile listeners, you’ll enjoy it. It’s a very clear, musical amp that has a ton of power just waiting to perform.

Should you choose not to install the bass remote, however, be aware that there’s no bass boost feature on the control panel. In that case, you’ll have to live without a boost adjustment on the amp.

Fun music, mucho bass!

All in all, I enjoyed the sparkling, crisp highs, and especially the subwoofer output. This is an amp that can really put out some serious power when you’re jamming hard.

It’s hard to believe how much power you get from such a little size: 350W x 1 at 4 ohms and 600W at 2 ohms (the minimum Ohms/subwoofer rating supported).

Never was there a problem with running out of power – this little amp is excellent for systems using subs and I got bass that hits hard any time I wanted it.

GM-D9065 vs GM-D9705: Are there any differences?

Pioneer GM-D9605 vs GM-D9705 5 channel car amp comparison image

While you might be a bit nervous about the possible differences, you’re in luck – there aren’t any. The 2 models are different only in the outside of the amplifier. The internal design, connectors, inputs & controls, and all specs are the same.

There are only 2 very small differences between the two models. They’re functionally the same amp inside.

As often happens in the industry both models are almost identical aside from a new look:

  • Internal components, power, sound quality, and specs are the same
  • The same bass remote is included with the D9705 as pictured with the D9605
  • Both the input connectors, controls, and wiring terminals are exactly the same

Some minor differences I found are the following:

  • The GM-D9605 has a glossy finish over a simulated carbon fiber pattern; the GM-D9705 has a slightly shorter top with a machined metal finish
  • The GM-D9605’s screw mount feet are a bit easier to access than the GM-D9705, giving a slight advantage at installation time
  • The 9705 has the same general internal electronics and many of the same components, but a slightly different circuit board (same power & performance specifications)

Other than that, there’s nothing worth mentioning.

Review summary – Should you get one?

After testing for some time and putting it through its paces, I have to say I’m very happy with the quality, sound, and power I got for the money. It’s a definite YES!

There are a lot of choices out there when it comes to 5 channel amps but the Pioneer GM-D9605/D9705 delivers some of the best all-around performance and value you’ll find anywhere. It’s an excellent choice for all but the most discriminating listener.

As an installer and audio fanatic, I really like how flexible it is, too. The features really let you tailor your sound a lot. The included bass remote adds that extra bit of fun when it comes time to crank up the bass.

While they’re almost the same aside from minor differences, I prefer the more modern style of the GM-D9705 over the 9605 model. I wouldn’t hesitate to recommend the 9605 if you like carbon fiber accents though.
Pioneer GM-D9605 GM-D9705 Editor's Choice product review image

These are affordable, solid amps that have all the power most people could want – with the sound quality that you usually expect from more expensive amps. Even better, they can fit under a seat since they’re so compact.

Head over now to find out why the GM-D9065 and GM-D9705 are some of the best-rated car amps sold today at Amazon.

  • Overall quality - 9.5/10
  • Sound quality - 8.8/10
  • Power & performance - 9.2/10
  • Installation ease - 8.9/10
  • Features - 9/10

Mid-priced 5 channel amps that really deliver, the Pioneer GM-D9605 & GM-D9705 offer an excellent - and affordable - way to power a whole system

While competitively priced, the GM-D9605/D9705 delivers serious power at 2 and 4 ohms. Bass fans won’t be disappointed, and neither will you if you want dynamic, crisp sound with plenty of power. Full-range sound is excellent, although it can’t match the detail level of competitors at twice the price. Bass is powerful, punchy, and enjoyable.

As a full-range system amp, it’s great for music and offers nice flexibility from an efficient & compact class D package. Quality is excellent, and the bass remote makes jamming hard even more fun. Try one on for size and you’ll love it too!


  • Good sound quality and clarity
  • Excellent power/CEA-2006 proven ratings
  • Bass remote & cable included
  • Bass boost feature works well
  • Great crossover flexibility
  • 2/4 ch front/rear input switch
  • High-level inputs w/ harness
  • Auto-sensing remote feature for high-level inputs
  • Bass signal input from RCA or derived from main chs.
  • Solid machined wiring terminals work well
  • Great looks
  • 0-18dB bass boost range
  • 12/24dB/Oct. sub crossover switch
  • Protection circuitry
  • Runs cool during use
  • Clear, detailed owner’s manual


  • No accent lighting on logo or body
  • Bass boost feature only works with remote
  • No separate protection indicator lights
  • Speaker and power terminals angled down slightly
  • Sound quality can’t match higher priced amps
  • 16′ 5″ (5m) remote cable may be short for some vehicles
  • Bass remote knob is small
  • No double-sided tape included
  • Top adjustment labels are harder to see

The Only Alpine KTP-445U Review You’ll Need: A Tiny But Amazing 4 Channel Mini Amp

Alpine KTP-445U review featured image

Sometimes getting good sound can be really tough – most especially if you have limited space. And it’s a shame, too, because often that means you’ll have to do without.

My, how things have changed!

This little power pack of sound is a modern-day solution to a decades old problem – getting great sound in a tight space. In my Alpine KTP-445U review I’ll provide a detailed an honest review of this fantastic like amp.


Alpine KTP-445U basics

Image of Alpine KPA-445U amplifier angle viewIn case you haven’t noticed yet, I’m a big fan of this little guy – and very happy with what Alpine has come up with! I don’t normally expect much from miniaturized amplifiers, but in this case I can honestly say I’m impressed.

First off, we need to set the stage by understanding what this little amplifier is and isn’t. It is not an end-all solution for the best audio quality money can buy. Let’s be realistic – you cannot get “perfect sound” in an incredibly tiny package for less than $150.

When it comes to sound, there are always compromises that must be made. It’s important to have reasonable expectations. Any good engineer will tell you the same.

What to bear in mind…

Also, it’s important to remember that as I’ll be explaining below, this is a class D type of amplifier. Class D amps have several pros and cons to be aware of (which I cover in detail). It’s important to remember this when you compare it to other amplifiers you may be thinking about buying.

I’ll be reviewing it based on my extensive knowledge of the technology and the amp both as an engineer and an installer. Also, I’ll be very fair – and very detailed – when I make comparisons to bigger and more expensive amplifiers.

Behind the technology: understanding the KTP-445U amplifier design

In only the last several years class D audio amplifiers have become one of the hottest audio technologies in the audio world. This modern technology has improved greatly since the first class D amplifiers hit the market years ago. I’ve found that despite this many brands still leave a LOT to be desired. Unlike the KTP-445U I have been very disappointed by some I’ve tried.

What is a class D car amp?

Simply put, audio amplifiers are all based off on one or more basic “classes”, or categories that classify the type of design they use. Despite what you might see thanks to advertising, a car amplifier class always fits into one of 3.

These range from Class A (fantastic clarity and ultra-low noise specs, but expensive and a power hog) to Class A/B and now class D. For the most part, any other kind you might run across is just a variation of one of those. (For a “class T” amp is still a class D – that’s just marketing).

Class D amps were once only used for subs but now are mainstream

Until recent years, Class A/B amplifiers were the most common because they’re cost-effective, relatively simple in design, and don’t waste as much power as Class A designs do. Also A/B amps provide low distortion and high power levels for a good watt-per-dollar value.

Despite their good points, conventional (A/B) amplifiers waste a lot of electrical power which is turned into heat rather than power to drive speakers. Today’s amps are still somewhat bulky and heavy due to the large metal body needed to dissipate the heat created.

A class D car amp is a newer type of amplifier technology used to produce audio power more efficiently.

How do class D amps work?

Diagram how a class D switching amplifier worksA Class D amplifier works by “modulating” (chopping up) the incoming audio signal and switching the transistors used to amplify it on and off incredibly quickly. This results in a fantastically efficient design without huge amounts of power being turned into heat like designs from the old days!

Class D amplifiers are based on a switching circuit design approach. This means the design modulates – or transforms – the incoming audio signal by chopping it up into a series of on-and-off waveforms as the input signal is received.

This is used to switch power-conducting transistors on and off thousands or hundreds of thousands of times per second. Older audio amplifiers (like class A or class A/B) conduct electricity nearly all the time they’re on.

While A/B type amplifiers are about 50-65% efficient, Class D amplifiers can achieve an incredible 85-90% efficiency!

Because of this the amount of power being consumed by a Class D amp is greatly reduced – resulting in no need for a huge, heavy amplifier body or lots of heat being produced. This was a huge step forward in technology.

Fun fact: Some bare-bones miniature class D amps are smaller than a pack of cigarettes!

Additionally, electronic component sizes have evolved to make these amps smaller and smaller. The decades-old problem of “How can I fit an amplifier into a tiny space in my vehicle?” is now just a bad memory.

No longer do you just have to settle for a weak 15W per channel stereo head unit. You’re now able to get many times the sound in a package that’s far smaller than anything imagined possible only 10 years ago.

Alpine vs the competitors

Something you might not be aware of is that there’s a lot of junk out there. Many of today’s car amp brands are no longer selling unique designs of their own. Sadly, many amplifiers on the market today, including compact Class D designs, are rebadged models that share the same internal components and mediocre design and only have minor cosmetic differences on the outside.

Over the years, lower-end brands were bought out by larger companies and exist only for marketing purposes, not for quality.

I’ve even bought one of these competing amps for test purposes (perhaps one day I’ll do a write-up) and was very disappointed with the design & sound quality. Noise levels were unacceptable and upon examining it I realized quickly it was another low-end version of an “amp on a chip” design.

In the audio engineering world, this means shortcuts were taken at the expense of sound quality and performance.

Alpine has relied on its great engineering resources and the KTP-445U is different from the competition because it’s an original and fresh design. I was not disappointed to find it has the trademark Alpine quality and innovation that became my personal favorite over the years.

Also, Alpine doesn’t use misleading power ratings and specifications, unlike other brands. The power ratings and sound quality specifications I’ll go into below are realistic and honest.

This is important to me not just as an installer and an engineer, but because I need to be confident in anything I review and recommend. I know how it feels to spend your hard-earned money on products that disappoint.

KTP-445U features and specifications


One of the biggest selling points is its size. The amp measures an amazingly compact 7 7/16″ x 1.5″ x 2.5″ (189 x 38.2 x 64.5 mm) in size. That’s smaller than pretty much any comparable amplifier available anywhere in the world today! I’m not kidding – I was expecting it to be much bigger. Basically all other high-quality Class D amplifiers below $200 today are at least 4 x the size of the Alpine.

mage of Alpine KPA-445U mini amplifier in my hand

Hard to believe how small it is. An amp with comparable power only a handful of years ago would have been 5 x times bigger. This one is small enough to hold in your hand!

Built-in high-pass crossovers

Originally I had expected the amp to be a “plain Jane” amp with NO features whatsoever, but it turned out I was wrong.

The amp actually, to my surprise, includes optional high-pass filters with selectable frequencies for the high-pass feature ( 60Hz, 80Hz, or 120Hz) to allow you to cut off speaker-distorting subwoofer bass if you like. Of course, you can always switch if off and run your speakers in “full range” mode if you like, but I normally prefer to block the lower bass frequencies.

My custom-installed 6.5″ speakers can’t handle the lower bass frequencies (they don’t do well below 50 Hz or so, so 60Hz is pretty close) so that’s very important to me.

High and low level inputs

Of course, I didn’t expect the Alpine to disappoint, but again they’ve done a great job in the design. The amp can work with both aftermarket head units via the or RCA inputs OR  speaker-level inputs from a factory stereo! In other words, you can use the KTP-445U to get a more powerful and better sound even if you have a factory-installed stereo in your vehicle.

The included color-coded wiring harness makes it easy and it’s a feature I’m sure a lot of buyers just like you will appreciate.

Quick tip: When adding an aftermarket amplifier to a factory system and connecting to speaker-level outputs, be sure to plan for getting some small-gauge speaker wire. Plan ahead for enough length to go from the speaker wiring connections to the amp (and back again, if powering factory speakers).

One thing I’ve learned in my years of car stereo installation experience is that the ability to connect to factory-installed stereos is a huge plus. The Alpine can be connected directly to factory speaker wiring in order to “tap off” and get a good audio signal to feed into the amp.

While not as good as being fed from an aftermarket head unit via the RCA inputs, it’s still a great option and in my experience, when done correctly, still sounds clean and there’s very little distortion or breaking up at higher volumes.

You can also disconnect the factory speakers once the KTP-445U is connected to avoid any distortion issues if that’s a concern for you.
Image of Alpine KPA-445U mini amplifier input harnessThe included signal input harness allows connecting both RCA (low-level) inputs or speaker-level inputs to the amplifier easily. Inputs are color-coded and explained clearly in the owner’s manual. A similar harness is used to connect to the output (to connect to speakers you’d like to use)

There are switches for audio controls on the bottom of the amp if you need to choose speaker level inputs or change crossover functions. As an added bonus, even if you’re using 4 speakers and only have a 2-channel input, the amp can provide a signal to all 4 outputs. You won’t have to buy a pair of RCA Y-adapters.

In order to bridge the amp, you’ll also need to set the 2/4 ch. input switch to 2 channel as well.

Image of Alpine KPA-445U mini amplifier control switches

Selectable option switches on the bottom of the amp allow you to adjust the crossover functions or split a stereo input into 4 channels. Also, this is where you must select the audio source before powering up the amp.

Front and rear gain controls

Image of Alpine KPA-445U mini amplifier controlsSeparate front and rear gain controls allow adjusting the amplification level depending upon the input signal strength you have. Speaker-level inputs, for example, might require turning it down, while RCA-level inputs may require boosting it a bit. It’s highly dependent upon what kind of stereo you have. In either case, it’s easy to adjust. The KTP-444U can accept up to 4V RCA inputs which are considered a “higher end” signal strength for aftermarket units.

Not too much I have to say here – the front and rear controls are easy to use and easy to adjust. Also, the gain controls “feel” good because good quality components (potentiometers, which are just adjustable resistors) are used on the circuit board. This means that when you adjust the gain levels it won’t change over time and will have a good “feel” when you turn them.


The amp can deliver up to 45 watts per channel into both 4 or 2-Ohm speakers, which is surprising because most miniature amps in my experience cannot handle 2 Ohm speakers. This means you could add extra speakers in parallel (to a degree) if desired.

It’s important to understand that 45 watts isn’t enough for extreme sound levels or to drive large woofers if that’s your goal. This amp isn’t designed for that.

I’d estimated with a good set of efficient speakers, however, you can get close to around 100dB of clear sound before it begins to give out due to its limits. For most people with normal listening habits, it’s plenty of power and you need not worry.

For reference, it may be helpful to know that most in-dash car stereos can provide only around 15W-18W RMS or so per channel of usable power.

Sound quality

For me, sound quality is extremely important.

It seems like every little bit of irritating distortion or poor musical reproduction I’ve heard really grates my nerves.

I’m happy to report the KPT-445U has great good sound quality and is very impressive for a tiny amp! If you recall what I mentioned earlier, this is a Class D amplifier. The benefits of Class D amplifiers are a fantastic size, great efficiency, and a lower weight, but one of the drawbacks is reduced sound quality.

I can say with certainty (and don’t just trust me on this – check the multitudes of other happy reviews) that the sound quality is very good. Remember when I mentioned earlier about how I bought another brand of car amplifier and was disappointed?

It was because the noise levels (the noise I heard when no music was playing) was far too high compared to the many amplifiers I’ve installed and listened to over the years. Not so with Alpine – they’ve done a great job in minimizing noise.

I can say I was pleasantly surprised. I came into my review of the KTP-445U expecting an “ok” experience but was honestly very impressed with what Alpine has done.

Here’s an excerpt from the company themselves:

In order to ensure that Alpine sound quality is heard at your ears, we’ve created a platform that offers an unbelievably low noise floor, taking extra care to ensure a clean signal path, with no extraneous interference. The end result: The Power Pack boasts 1 Watt Signal-to-Noise Ratio of 82dB or better.Alpine Electronics

In my opinion, this says a lot. Why? Because it takes additional engineering time and manpower – in addition to planning – to make the effort to make better sound quality a design goal rather than a forgotten number on a spec sheet somewhere.

I’d much rather pay a bit more for something I know is designed right from the beginning and I know sounds great rather than just made to be “ok” and barely passable.

Quick tip: If you have to increase the gain level greatly it also increases your chance of hearing the base noise level in any amplifier, including this one. For best results, the amp should have a good, strong signal so that the gain can be turned down, resulting in the cleanest output possible.

And by the way, for you spec nerds like me, the specs on this little amp are great. According to the company, the Power Pack distortion actually decreases at higher frequencies, resulting in a clean and clear signal where your ear is most sensitive to distortion (less than 0.03% THD+N @ 1W, 1% THD+N at rated power).

Here are some of the most basic specifications you need to know:

Image of Alpine KTP-445U technical specifications

Note: the KTP-445U mini amp – despite its tiny size and simple design can drive 2 ohm speakers up to 45 watts each. I was honestly impressed and didn’t expect that.


Alpine KTP-445U under seat installation

Great for installation under seats and just about any small space you can think of.

The great thing about the size is that you can fit it in incredibly small spaces which were unheard of years ago. A great example is some of today’s vehicles in which there’s extremely tight space inside the dashboard, perhaps beside or behind the current stereo.

It’s a great solution to the most difficult installation problems which years ago would have required either a ton more money to be spent by customers or unfortunately cause some people to just “give up’ as there weren’t any other options.

It’s also a great fit for boats as well but you’d need to ensure it is protected against corrosion and exposure to the air and saltwater since it’s not marine rated. You can mount the tiny powerhouse by using the included zip cable ties to attach it to the nearest available wiring or mount it permanently using the included brackets and self-tapping screws.

Don’t forget that because of its light weight you could also use double-sided adhesive tape or Velcro if desired for convenience.

Note: Because it is so efficient and draws less electrical current than traditional amps, you won’t need to get a heavy-gauge wire installation kit and run extra wire. It’s possible to connect it to a nearby 12V supply from your car stereo, for example.

Accessories included with the KTP-445U

Image of Alpine KPA-445U included items

  • Mounting brackets (2)
  • Self-tapping screws (4)
  • Cable ties (2)
  • Required wiring harnesses

I would definitely suggest getting a few inexpensive items to make sure you’re better prepared for installation, such as:

  • A roll of speaker wire
  • 14 or 16 gauge power and negative wire for installations placed further way
  • Wire crimp connectors (“butt connectors”) and a crimp tool
  • A small bag of 6″ or 8″ zip wire tie

Bridging the amp

Need more power? Amazingly – and to my surprise – it’s not a problem with this amp.

Just switch the 2/4 channel input switch to the 2 ch. input mode. Then connect the output speaker wiring in bridged mode and you’re done!

You’ll have 90W RMS per channel of high-quality sound at your disposal. Honestly, I didn’t expect that for an amp so small, but once again the engineering quality made all the difference.

Just one more reason I’m impressed with it.

KTP-445U vs KTP-445A

Alpine KTP-445A image

The KTP-445A looks very similar to the KTP-445U. However, it’s designed specifically for Alpine head units 2005 and later, not for RCA or high-level inputs from others.

When shopping it’s important to be aware of the KTP-445A model as it can cause a bit of confusion and comes up in search results.

The KTP-445A is a model of the KTP-445U (where “U” stands for universal; “A” stands for Alpine head units) designed only to work with Alpine model car stereos. The wiring harnesses included don’t allow using RCA connectors and the standard speaker-level inputs.

Aside from that, both share the same basic design and performance.

There are a few drawbacks to know…

I would have liked to have an optional low-pass crossover feature in addition to the high pass design. Perhaps it was a cost-cutting or design compromise decision that had them remove it. I’m not sure.

I have somewhat mixed feelings regarding the location of the switches used to control sound options. They’re located on the bottom, whereas ideally, they’d be accessible from the side or top. But ultimately that’s a minor complaint.

Review score & summary

All in all, in my opinion, the KTP-445U is a wonderful little 4-channel amplifier with great sound quality. It’s truly a dream come true if you want great sound but have especially limited space.

It’s not for those who need extreme power and volume levels. You can’t drive subwoofers or very high-volume speaker systems with this amp, but what it does it does well!

Alpine KTP-445U review featured imageHead over to check out the current price and see the fantastic buyer reviews at Amazon.

  • Quality - 9.5/10
  • Sound quality - 8.7/10
  • Installation ease - 9.5/10
  • Features - 7.5/10

A well-designed and great sounding miniature car amplifier. One of the best compact amps I've seen.

Alpine has done it again with their approach to getting the most power and sound out of a tiny package. It’s a great upgrade for weak aftermarket or factory stereos. Thanks to its design it’s a great general-purpose 4-channel amp that can fit a wide variety of installation and audio system needs. You’re paying a few extra dollars for better sound and better design – and that’s exactly what you’ll get. You won’t be disappointed.


  • Amazingly small size!
  • Great sound, low distortion, and low noise design
  • Can handle 2 ohm speakers (4 channel mode)
  • 4 channel outputs
  • Bridgeable to 90W RMS x 2 channels
  • Selectable 2/4 channel input switch (no Y adapters required)
  • Speaker level inputs
  • Installation accessories included
  • Great power: 45W/channel
  • Built-in optional high-pass crossovers
  • Simple installation / no large wire required


  • No low-pass crossovers
  • Option switches are located on the bottom as opposed to top or sides
  • Could use more zip ties in package

Alpine MRV-F300 Full Review And Details: A Great Sounding 4 Channel Amp You Can Afford

Alpine MRV-F300 amp on top of its package

I’ve been a huge fan of Alpine products and have been for years. I love my 4 channel amps and I’ve been enjoying fantastic sound for many years now.

Having the flexibility that a 4 channel amp gives is great when it comes time to upgrade your system later.

When it comes down to it, you don’t need a super-expensive amplifier to enjoy great sound quality. However, you do need to pick one that’s a well-rounded great choice.

I’ll tell you all you might want to know about the MRV-F300 before buying. Read on to learn more.


Alpine MRV-F300 review – First impressions

It’s a great looking amp, very compact, and housed in a well-designed dark brushed metal chassis. It feels solid in the hand, but it’s still relatively lightweight compared to conventional older amps of the same power rating.

I have owned other amps in the past with the same power rating and they easily weighed 3 times as much as the MRV-F300 does! It measures just under 5 lbs (around 10 kgs).

Build quality is great, and I notice there aren’t huge gaps or misaligned parts like on cheaper amps of the same Class D technology. I’ve tested other type D amps before, and easily noticed they weren’t put together well or felt a bit flimsy and just didn’t feel solid. That’s not the case here.

Holding Alpine MRV-F300 amp in my hand

The amp looks great and the connectors are high-quality. You can make more reliable connection unlike lesser amps with standard screw terminals. Fit and finish are excellent, with no big gaps or sloppy assembly. The blue light on top glows when it is turned on (but not TOO bright, it’s not annoying). My opinion so far? NICE!

Connectors are very high quality and use hex-keyed screws to securely hold wiring connections. Connectors are clearly labeled, and take the guesswork out of bridging the amp if you choose to do so for more power.

The power connectors are circular inside and 8 gauge power wire will fit and is recommended for installation.

I really like what Alpine has done with the protective end caps it comes with – unlike amps in the past, they’re easy to get on and off.

They snap on and off! If you choose to mount it under a seat in your car or truck they’re great for protecting the wiring from shorts if you happen to have tools or coins lying around in your interior like I do at times.

Also, it just plain looks nice with them on!

By the way – upon opening the box you’ll find an Alpine Verification Certificate detailing the operation and performance of the amp you bought! Very nice.

MRV-F300 amplifier design and performance details

A huge advantage – compact size

Image of MRV-F300 amplifier top

The MRV-F300 has a cool glowing light on the top when powered to indicate it’s on. I love the compact size and honestly, I’m impressed with what they’ve fit into such a small package (Shown with end caps installed)

There’s a huge range of Class D car amps on the market today and most are pretty compact. The problem is that a well-designed car amp with decent power and GOOD quality sound requires a bigger circuit board and more parts – and that means a bigger size.

Alpine, for several decades, has been several steps ahead of the lesser brands. They use surface-mount component technology (SMT) to reduce the size required in order to make a smaller and better-sounding amplifier.

Measuring only 7 7/8″ W x 6.5″ D x 2 3/16″ H (200 x 165 x 55 mm) it’s crazy small and can fit in creative places that older amps could never even come close to fitting in!

That’s a huge advantage! You could even fit one amp under each seat in some cases for a great way to have a multi-amp system that thieves won’t see.

Class D amp technology

Class D amplifiers are one of the most recent developments in the audio world. Unlike conventional Class A/B designs (which most car audio amps still use to this day) that are around 50% efficient, a Class D amplifier uses ultra-fast switching technology to bring efficiency to near 90%!

This means since you are no longer wasting huge amounts of power (which turn into heat, by the way) the amp can be reduced greatly in size and doesn’t need a huge power supply internally.

However, as I mentioned at the beginning of my review, there’s something you need to know: Class D amps have higher “noise floors”, another name for the baseline noise or “hiss” level you hear when the gain is turned up.

Also, these types of amplifiers must be well-designed to ensure the technology use doesn’t modify your music signal (distortion) when amplified.

That’s what they’ve done, as Alpine uses their own engineering rather than repackage and relabel a lower-end audio amp as some competitors do.

The end result is the ability to provide up to:

  • 50W RMS per channel into a 4 ohm speaker x 4
  • 75W RMS per channel into a 2 ohm speaker x 4
  • 150 watts RMS x 2 bridged output at 4 ohms (4-ohm stable in bridged mode)

Performance and sound quality

Sound quality is just great as you’d expect from Alpine: music is full and clear, highs are bright and crisp, and bass is solid and easily drives speakers without giving out. It’s an excellent sounding amplifier and a winner! In the past, I had my doubts about Class D car amps (after having a few bad experiences) but the MRV-F300 has changed my mind. It’s that good.

Bass hits hard and has a great impact, just as you’ve come to enjoy from conventionally larger amplifiers.

If you’re planning to drive subwoofers with moderate power and volume (up to 150W each) you won’t be disappointed. If you need slamming bass, however, I’d consider the sibling MRV-M500, a mono amp with much more power available in the same size.

I have excellent hearing and based on my audio design & listening experience, I can definitely recommend this little powerhouse.

Alpine MRV-F300 4 channel amp end viewThe MRV-F300 features full range, low pass, or high pass crossover settings including 50-400Hz adjustable cutoff. A bass EQ (boost) feature is built-in too.

Audio controls

The crossover functions are easy to use. Controls and switches have a good, solid “feel” to them. One thing I’ve always noticed about Alpine Electronics is their products use good components that don’t feel sloppy when making adjustments. They also don’t change due to vibration over time after I’ve spent time & effort setting them up.

This amp is no different.

Note: the bass EQ boost is works only for the 3/4 channel pair when turned on. I’ve taken off points in my review score at the bottom as this feature in my opinion should be on 1/2 also.

One thing you need to know is that because it’s a Class D amp, by nature the noise level can be heard more when the gain is turned up higher. I definitely recommend adjusting the gain to a lower level that will still give adequate volume when the stereo is turned up high.

Alpine has done a great job in designing the amp, but it’s one of the trade-offs of this type of amp. Still though, it sounds wonderful and noise levels are basically imperceptible in most cases.

Additional features and installation

The great news is that it’s still easy to install – just like any other car amp as screw mounting is used to mount on tabs on each end of the amp (one pair of tabs on the control end and one pair on the power & speaker connection side.

It also works with speaker level inputs so it’s great for factory stereos too!

Alpine MRV-F300 installed under seat

The amp fits great under seats and can still leave room for speaker crossovers! Here’s an example of a custom install using the amp when space is limited.

Actually if needed, because of its light weight, in more difficult installations you could even use industrial strength Velcro or some type of reliable double-sided tape to mount it if necessary. The amp won’t heat up and cause the adhesive to lose strength, unlike amps in the past.

As I mentioned earlier it looks more professional to use it with the end caps snapped on, but I’ll leave that up to you to decide.

Quick tip: Because the amplifier’s mounting tabs face inward, it may be a bit hard to install under a seat. Be prepared to use a short screwdriver or even remove the seat to make your job easier when installing.

Accessories included

You’ll get the following inside the box:

  • 7.5″ Speaker-level input harness
  • 2 snap-on terminal covers
  • Four 3/4″ Self-tapping hex-head screws
  • Owner’s manual (English/ French/ Spanish)
  • Alpine Verification Certificate

…so you’ll need to remember to pick up whatever else you need before you start your installation, along with an amp wiring kit. I recommend picking up a good quality but great-priced 8 gauge wire kit like this one I found at Amazon.

It’s a lot less hassle to be prepared, and you sure don’t want to end up paying too much or having to run out for supplies while in the middle of your install work!


For your convenience I’m including the specifications directly from the owner’s manual as well as details I’ve found myself.

Alpine MRV-F300 Specifications
  • 75W RMS x 4 (2Ω, 14.4V, ≤1% THD+N)
  • 50W RMS x 4 (4Ω, 14.4V, ≤1% THD+N)
  • 150W x 2 @ 4Ω
  • S/N ratio: >81dB @ 1W, >98dB @ rated power
  • Damping factor: >90
  • Front/rear adj. crossovers: Hi/low-pass, 50-500Hz, 12dB/oct.
  • 3/4 channel bass EQ feature (50Hz, +12dB)
  • High-level speaker inputs
  • Blue accent power-on light
  • Same power in a 40% smaller chassis
  • Evolution to Class D digital platform
  • Snap-on terminal covers for easy installation
  • Fuse: 40A
  • 1 year warranty
  • Compact size fits under seats
  • Dimensions: 8-1/4″W x 2-3/16″H x 7-15/16″D
  • Weight: 3.75 lbs (1.7kg)

You may have noticed that the signal-to-ratio ratio specified at 1W is lower than typical amplifiers. As I mentioned earlier, that’s an inherent design trait of Class D amps, but in practice with good speakers and the amp being sent a good signal level, it’s not really an issue.

I’m still pleased with the sound quality and wouldn’t recommend it if I didn’t feel you would be too.

Also note that the EQ boos is +12dB, in case you weren’t aware. That’s a very noticeable amount of bass increase.

Review score, pros & cons, and my final thoughts

I love this amp. For the money (it sells for a very reasonable price, usually somewhere close to $150 dollars or so) it’s a great buy.

As both an installer and a music lover I’d recommend it to nearly everyone except those who want extremely high signal-to-noise specs.

The MRV-F300 doesn’t disappoint as it’s a great performer – and definitely a great value, too!

Alpine MRV-F300 amplifier Editor's Choice image

Head over now to find out more and see why its one of the highest rated compact amps at Amazon.

  • Overall quality - 9/10
  • Sound quality & performance - 8.7/10
  • Installation ease - 9.2/10
  • Features - 8/10

A fantastic, great sounding 4 channel amp you'll be proud to own and can fit into small spaces

Is it small? It sure is! However, thanks to the superior Alpine design quality both music reproduction and power output are impressive for such a compact size. It’s a great performer musically and I love it. While many similarly priced class D amps by nature have a higher noise level than conventional Class A/B amps, Alpine has done a great job in minimizing noise.

Music is crisp, loud, and most of all enjoyable. This is an excellent amplifier for both aftermarket or factory stereos – with its small size it can fit safely away under seats or in storage areas. Factory systems gain the additional benefit of an auto-on sensing feature when the speaker level inputs are used. Not only that, but the included snap-on end caps round off a great-looking appearance nicely…and it’s priced close to the same as lower-quality competition models. Don’t pass this one up!


  • Excellent sound for a Class D amp
  • High efficiency – runs cool
  • 8 gauge wire terminals
  • Flexible crossovers built in
  • Bass boost switch
  • Small size fits in many small areas
  • Great looking finish & nice power-on light
  • End caps provided for clean install
  • Bridgeable for 150W RMS each channel pair
  • Speaker level inputs


  • Bass EQ boost only on channels 3/4
  • Normal Class D lower signal-to-noise ratio (improves as power output goes up)
  • Closed power terminals mean its difficult to fit 4 gauge wire
  • Mounting tabs face inward rather than outward – no option to change them
  • No remote knob available unlike the sibling MRV-M500
  • No 2/4 channel input switch

Rockford Fosgate P300-12 & P300-10 Full Review: A Powered Car Subwoofer Done Right

ockford Fosgate P300-12 review image

Powered subwoofer enclosures are a great option for too many reasons to list here. I’ve installed many over the years, too. However, it’s critical to buy one that actually delivers the bass you’re looking for.

The P300-12 (and its sibling the P300-10) is a subwoofer enclosure that stands out from others in many ways. But how does it rate? How does it sound? And most importantly, will you be happy with it?

In my review, I’ll cover everything you need to know in detail before buying.


First impressions and evaluating the quality

Rockford Fosgate P300-12 first image

The P300-12 is solid and well-made and definitely comes across as such. The black material covering it is an industrial heat-activated vinyl. It’s scratch and ding resistant. Nice!

Note: as it’s the sibling to the P300-10 which features a 10″ subwoofer, many features and performance points are the same. I’ll try to point out differences where they exist.

First impressions

When I got my hands on it and pulled it out of the box I thought to myself right away Man, this one’s solid!” and I’m sure you will too. It even has that “new speaker box smell” too, the one always gets you excited when you first get your hands on some awesome new car stereo subwoofer stuff.

The whole thing is very solid, being made from 5/8″ medium density fiberboard (MDF), a material popular for speaker enclosures as it’s cost-effective but also has high density. This is a necessity for high-powered subwoofers as a dense material is needed to resist flexing during air & cone motion, and to trap sound for producing the bass you love.

The Rockford Fosgate design uses a sealed enclosure rather than a vented one as many car powered subwoofers do, so it’s helpful to bear that in mind when buying.

At just under 30 lbs (13.4 kgs) it’s kind of heavy – this thing is not flimsy! This is a “real” speaker enclosure and not a watered-down pipsqueak of a speaker enclosure like some others I’ve seen.

Parts & assembly line up well and it looks well done. No sloppy construction or “cheap-looking” production methods appear to be used. I’m really curious about the connection & wire terminal section, one of the biggest advantages the P300-10 & -12 subwoofers have over others sold today.

It measures about 15″ (h) x 19.8″ (w) x 11″ (d, at the bottom) so you’ll need to measure and make sure you’ve got room in your vehicle. The 10″ version measures nearly the same, at 13.3″ x 17.9″ x 8.8″ in size. Ideally, you’ll be able to fit but I know from experience that sometimes even an inch can make all the difference!

Power connections and audio inputs

ockford Fosgate P300-12 connection block

The connection & input plate brings everything to one place and makes installation (and removable) pretty simple. It’s much more well-thought-out than other products I’ve seen and used. Here you can make all connections for the power & and audio input signals, as well as adjusting bass using the bass boost feature (Punch EQ), low-pass crossover, and 0/180 degree phase control.

Rockford Fosgate has apparently put some good engineering design though into the connection “plate”, a square assembly on the left-hand side of the enclosure (it’s on the left-hand side when you’re facing the front of the speaker).

What really sets it apart (from the cool features that provide some big advantages I’ll get into below) is that the power connector allows for quick connections and disconnection of the positive, negative, and remote-on wiring.  After that, you can simply unplug the audio input connector and bass remote plug and you’re done!

That’s a huge advantage as with most similar products you have to disconnect each wire individually every time you remove it.

That’s fantastic for those individual instances in which you’re running out of cargo space and need to remove it temporarily. Or maybe you’ll be out of town for a few days and don’t want to leave it inside for thieves to steal it while your vehicle is at airport parking. I can think of many more examples of why this is a great feature to have, especially for leased vehicle owners who know they’ll have to take it out one day.

Connecting audio sources

The P300-12 can connect to both speaker level or aftermarket stereo system using the supplied harness which provides RCA jacks to connect. However, for speaker-level inputs, you’ll need to cut the harness and attach the wiring with crimp connectors or some similar method.

That’s one thing I don’t like – I would have preferred a slightly simpler option like having the speaker-level inputs wired next to the RCA jacks to allow the buyer to connect to them.

That would avoid the need for cutting the wire and reattaching it later if you needed the RCA connections when your system changes.

Turning on the built-in amp – extra features you’ll like

Fortunately, there are 3 ways, not just one (unlike other products) to turn the amp on & off:

  1. Auto-on using audio sensing
  2. DC OFFSET – this features needs only 6V to switch it on
  3. +12V remote on wire (standard way)

The first 2 are great because normally an amplifier remote-on wire uses a +12V signal to control it for on or off purposes. This keeps an amp from draining the vehicle battery when not in use. However, some vehicles today are harder to work with and an accessory-switched +12V wire can be hard to find.

The P300-12 provides 2 great ways to work around that! And I personally really can appreciate that. However, note that the DC offset feature only works for high-level inputs. Audio sensing works for both.

Amp wiring connectivity

The removable connector which firmly slides in or out of the connector plate accepts 4 gauge wire with set-screws to keep the wire secure and from loosening. I like it.

Audio controls

Gain, in case you’re not already familiar with it, adjusts the amplification factor of the system based on how strong of an input signal is available. Ideally gain is set low, when possible.

The low-pass only crossover is easy to use and is adjustable from 50 to 200Hz, with a 12dB/octave Butterworth filter cutoff. You can’t bypass it as the system is designed only for low bass response.

As bass sound waves are very large in size and the subwoofer is most likely located in the rear, in many installations bass sound slightly out of tune with the front speakers. In that case, changing the phase switch to 180 degrees, which inverts the speaker movement, may improve it.

Power/Protect LED

A bi-color LED is used to indicate power-on a green power-on condition or show red when a short circuit or overload condition is detected. In that case, the amp will shut down automatically. It’s a good feature I like. Simple, but effective.

Of course, you’ll have to remove the subwoofer to begin troubleshooting if a problem puts the amp in that state.

Remote Punch feature

ockford Fosgate P300-12 remote Punch control

The remote Punch control is an easy to use add-on (included) with a long cable and 3.5mm headphone-style plug which plugs easily into the connector panel on the subwoofer assembly. With it you can adjust the bass level from the front of your vehicle.

It’s a nice touch, and the control is easy to use. I don’t particularly like the “ovalish” shape of the assembly for the remote, but that’s a minor complaint. It has a good “feel” and is a nice touch.

The owner’s manual

The owner’s manual is great and one of the best I’ve ever seen! It’s relatively brief but has measurements, thorough installation details, and clear, detailed information. I really like it, and I’m confident it will be helpful to people who aren’t very experienced with car audio installations.

(click to enlarge)

ockford Fosgate P300-12 manual example

The instruction manual is clear, detailed, and explains the amp features and connections very well. I think it’s a great example of an owner’s manual done right. So, don’t sweat the instructions! That’s one more great thing about the P300-12 and -10.

10″ vs 12″ version comparison

To summarize everything, the P300-12 and P300-10 are very similar. Check out this comparison:

P300-10 Specifications
  • Woofer size: 10″
  • RMS power: 300W
  • Crossover slope: 12dB/octave
  • Cross. freq.: 50-200Hz
  • Punch Bass: Var. 0-+12dB @ 45Hz
  • Freq. response: 35Hz – 200Hz
  • Input sens.: 100mV – 3V
  • Fuse: 30A
  • Size: 13.3” x 18.0” x 8.9”/5.9”
    (33.7cm x 45.7cm x 22.6/15cm)
P300-12 Specifications
  • Woofer size: 12″
  • RMS power: 300W
  • Crossover slope: 12dB/octave
  • Cross. freq.: 50-200Hz
  • Punch Bass: Var. 0-+12dB @ 45Hz
  • Freq. response: 35Hz – 200Hz
  • Input sens.: 100mV – 3V
  • Fuse: 30A
  • Size: 15.0” x 19.8” x 11.0”/7.0”
    (38.1cm x 50.3cm x 28/17.8cm)

Ultimately it won’t make a huge difference which one you pick, but like I always recommend, if you can fit the 12″ in your vehicle, buy that one. The reason why is that there’s no substitute for cone size. A bigger subwoofer can move more air and hence produce a bit more bass sound and volume, sometimes with more impact.

Interestingly enough, there doesn’t seem to be much difference, if any, in costs between the 2 models depending on where you shop. However, as I’m reviewing (mainly) the P300-12 I’ll refer to that here. Expect to pay close to $200 if you shop smart. Otherwise you could end up spending an extra $50 dollars elsewhere.

One note about Rockford Fosgate and the specifications

Rockford Fosgate provides industry-standard Consumer Electronics Association (CEA) ratings for the performance of their amplifiers and speakers. What this means to you is that they’re not inflated (or made up!) numbers like you’ll find with many other brands – they’re reliable and accurate.

Rockford Fosgate Klippel image logCEA logo

Klippel is a speaker certification program Rockford Fosgate uses to deliver some of the best subwoofers on the market. The CEA-2006 standard was established to assist consumers with the misleading power ratings that have plagued the industry for decades and mislead consumers. A handful of industry-leading car audio companies support these reliable means of rating their products.

Fitting the subwoofer enclosure in your vehicle

You probably already have a few great ideas about where you’d locate the powered subwoofer, but since it’s so convenient it can work really well in so many applications:

  • In car trunks
  • In the rear of Jeep Wranglers and other sport vehicles
  • In cars with limited space like sports cars or 2-seat coupes (behind the seats)
  • Underneath rear fold-up seats in truck cabs or in the rear floorboard
  • In SUV cargo spaces

ockford Fosgate P300-12 truck

ockford Fosgate P300-12 in car trunk

ockford Fosgate P300-12 in SUV cargo space

The RF P300-12 looks great and fits in a wide variety of spaces in vehicles. I like the modular design and it looks professional and not at all cheap in just about any installation.

Honestly, you’re really only limited by your imagination if you have (small) room to fit it.

The one “real” (well, ok, it’s still pretty minor) issue is that you really do need to strap down or mount the subwoofer box to keep the whole thing from sliding around or falling if it’s standing upwards. At close to 30 lbs weight, I’m sure you can understand why I saw that.

ockford Fosgate P300-12 manual example

You’ll probably need to plan for how you’re going to keep it in place and figure out something. A great idea would be some inexpensive elastic bungee cords, for example. Or perhaps a factory cargo strap like in the back of this SUV.

Plan on having to pick up a few as there aren’t any type of straps included with it as I would have preferred to have seen. That’s another minor complaint I have. The subwoofer doesn’t include any kind of straps of any sort to help with installation.

Evaluating the speaker grill

The speaker grill is made of a nice mesh metal and is well-secured to the box. It looks great and doesn’t obstruct sound at all. I can’t understand why some competing products have no grill or have one that can allow objects to touch and potentially damage the speaker cone. That’s not a concern here, and it’s a nice touch.

How good does it sound?

The sound? Ah yeah! Bass is smooth, punchy, and sounds very nice. I really like it.

Music tests

Fergie Glamorous subwoofer track image

Playing some familiar test tracks with bass that helps to notice any flaws in performance, the P300-12 responded well and really sounded satisfying. How can you do the same? 1) Buy it, 2) install, and 3) enjoy!

Pop music like Fergie’s 2007 Glamorous or Outcast’s So Fresh, So Clean, great tracks with a hearty bass beat, produced responsive, beefy bass that really juiced up the low end.

The P300-12 puts out that great bass sound that makes music so much livelier and fun than a system without it. I really like how it made my music change from just sound to, well…music!

Adjusting the Punch Boost (centered at 45Hz, by the way) adds just the right level of extra emphasis on low-end bass that “hits” and sounds great!

While at high volumes the P300 didn’t produce the same bass as two equally-rated 12″ woofers in a larger or vented box, but honestly, that’s to be expected. I didn’t mind as it does it’s job and does it well – without the extra hassle or having to give up valuable cargo space like a huge speaker box normally would.

Bass is clear and filtered very well – no noticeable vocals or upper-end noise with the low-pass filter set to around 80Hz.

Ultimately, the P300 produces excellent low-end sound with great volume – it doesn’t sound “thin” or shallow like a tiny car powered subwoofer that has to compromise a lot.

Final thoughts and review score

What do I think? I like it, and it’s a good choice. The bass is satisfying and is “real” bass, not some weak version you’ll get from cheaper and poorly-designed models.

You’re not going wake the whole neighborhood up and rattle all the windows, but you’ll definitely get great sound and a lot of high-quality bass with good volume that you’ll enjoy.

Head over and have a look at the fantastic P300-12 powered subwoofer at Amazon.

  • Quality - 9.7/10
  • Sound quality - 8.8/10
  • Installation ease - 9.3/10
  • Features - 8.7/10

A high-quality powered subwoofer that really delivers - but in less space. Great sound you'll enjoy!

The P300-12 (and slightly smaller P300-10) is an all-in-one powered subwoofer that performs well for its size. Features and quality are excellent. I’m impressed by both the appearance and performance for the price. Sound quality is great: detailed, clear bass with good volume and punch.

Excellent owner’s manual. Good engineering went into the quality power connector which makes removal easy. You won’t beat more costly (and larger) subwoofer systems in a sound off, but for what you pay it’s very satisfying. Cheaper alternatives exist but most can’t match the performance and quality. A great choice for factory or aftermarket stereos.


  • Set-screw power terminals accept 4 gauge wire
  • 3 on/off remote switching methods provided
  • Accepts RCA and speaker-level inputs
  • Easy connect/disconnect and removal
  • Good size for the sound
  • Quality material, very solid (5/8″ MDF)
  • Recessed connector plate doesn’t stick out
  • Industrial vinyl material protects the enclosure, looks nice
  • Great speaker grill
  • Controls are simple to adjust and well-documented
  • Provides thermal overload and short-circuit protection
  • Vertical wedge shape allows the system to fit many vehicles
  • 300W amp provides plenty of power
  • Subwoofer itself is good quality, not high-end but performs well
  • Punch bass remote is included & works well
  • Rockford specs are CEA-2006 compliant/reliable
  • Owner’s manual is well-done, clear, and helpful


  • No straps included which are helpful for many installations
  • No installation brackets for permanent mounting
  • May tip over when moving if not secured
  • Audio signal harness must be cut if speaker inputs used – odd design
  • Heavy – almost 30lbs
  • Sealed enclosure can’t quite match the volume of vented box
  • No daisy chain option for connecting two P300-12s easily

Kenwood KAC-M1824BT Review – A 4 Channel Bluetooth Marine / Motorcyle Amp That Makes Music Fun

Kenwood KAC-M1824BT review featured image

Shopping for an amplifier for a boat or even a motorcycle is especially challenging.

What some people don’t know is that electronics installed in vehicles exposed to the elements and air moisture (especially boats and other marine vehicles) are subject to additional problems like corrosion.

In my Kenwood KAC-M1824BT review, I’ll go into great detail about how the marine amplifier measures up and if it’s right for you or not.

Is it just hype, or is it a great way to enjoy easier music while you enjoy the outdoors? Read on to find out more.


Kenwood KAC-M1824BT – First impressions

Kenwood KAC-M1824BT Bluetooth amplifier front imageWhat really strikes me at first is the small size and the great-looking finish.

The amp measures a tiny 6-11/16″ W x 1-13/16 H x 3-7/8″ D. The first thing that strikes me (besides the amazingly small size) is the build quality and how good it looks.

The connectors (including the RCA jacks, too) are protected from moisture and salt or dirt by plastic covers you can remove as needed. It’s a great touch I like considering where the amp may end up installed.

The fit and finish are great: parts line up correctly, indicating great that Kenwood quality which the brand is known for.

Kenwood isn’t reselling another brand’s electronics with some small cosmetic changes and putting their logo on it as some cheaper brands are doing nowadays.

I’m glad. I wanted to be impressed by this little amp – and I was not disappointed.

I absolutely love how Kenwood is bringing new technology into play in a miniature package that can be installed nearly anywhere!

Image of Kenwood KAC-M1824BT amplifier end

Build quality is great! The product is assembled professionally and compactly – no signs of the sloppy handiwork prominent in cheaper amps. The wiring harness connector (shown on the right) provides wiring outputs for the speakers, power, and remote on lead (if used, see notes below). To the left is the USB charging jack that allows you to charge your phone while you play music!

More about the amp and what it can offer you

Audio amplifiers haven’t changed much over the years. They’re powered by a +12V supply and connect to speaker level wiring or RCA cables on a head unit for an audio signal.  Additionally, they’ve always been somewhat large and heavy.

At least that’s how it used to be – the Kenwood KAC-M1824BT is actually significantly different in a way that really gets me excited for all the installation possibilities and great ways it can be used.

Bluetooth is a fantastic way to play music, too.

Image of Kenwood KAC-M1824BT amplifier end with caps

The amplifier is neat and compact, with RCA jacks, the wired remote connector, and audio controls on one end. The other end features the wiring harness for speaker level inputs, power connections, and speaker outputs. End caps are included to protect the unused connectors from allowing debris or water inside.

Marine amplifiers are basically the same as car audio amps with a few additional changes to make them durable when exposed to harsher environments like those in a boat or outdoor vehicles.

A unique way to enjoy music – directly via Bluetooth!

Unlike other amplifiers, Kenwood has created a cool new design that makes installation and enjoying music much easier for you.

You’re no longer forced to install a head unit in addition to installing an amp when you need more powerful and clear sound. And you won’t have to deal with an old, low-quality (or broken!) stereo you’ve already got.

Not only that, if you’re reading this there’s a great chance you’re just like me – I’m constantly listening to streaming music or music files on my phone.

I love the amazing choices I can enjoy from Pandora, Spotify, and yes, even YouTube! The possibilities are fantastic because I’m only limited to what my smartphone can play – which is pretty much anything!

The amp basically allows you to enjoy music in 3 ways, depending on your installation and usage needs:

  • Connect to an aftermarket stereo using RCA cables
  • Connect to a factory or aftermarket stereo that doesn’t have RCA jacks by using speaker-level inputs
  • Connect to Bluetooth

Note that it’s not mandatory to connect to a stereo at all. That’s what I like so much about it – you can have a completely hidden sound system installed away from thieves who are just looking for an easy opportunity to steal a nice stereo.

By using only your smartphone as a music source it’s possible to use no stereo or completely remove the existing one!

Bluetooth connectivity

The KAC-M1824BT features a wired remote which acts as a remote control for your phone’s music app and for pairing. Pairing itself is easy as long as you follow the instructions outlined in the owner’s manual:

  1. Press the SRC button on the controller to enter Bluetooth mode
  2. Press and hold the “>||” button
  3. Use your Bluetooth on your phone to connect to the amp

Image of Kenwood KAC-M1824BT Bluetooth controllerThe wired controller is easy to install using the flush-mounted holder or double-sided tape (both are included). Using the remote, you can switch between songs in the blink of an eye! Even better, if you activate Bluetooth mode you can control tracks, volume, play/pause features, and so on without even touching your smartphone! Very nice!

When paired, the controller’s backlight illumination will light up in blue and you’re ready to go!

From there on out you won’t need to use the same pairing process anymore – just turn on Bluetooth on your smartphone it will connect automatically. Up to 3 devices can be paired/stored in the amp.

The remote works just like any remote control: for many music apps on your phone, you can control playback/pause, skip forward and backward, and even adjust the volume!

I love the feature as it’s extremely convenient. You can store your phone and won’t have to touch it – just use the wired remote!

Bluetooth sound quality

Audio quality over Bluetooth is great and it supports the A2DP and APT-X protocols for high-quality, higher-bitrate audio sound reproduction.

If you’re not already familiar with those, they’re more updated versions of protocols used in Bluetooth software to enhance how much of a music signal can be reproduced. Basically, they’re currently one of the best protocols available.

I personally use APT-X as my Sony Xperia phone supports it, and I love how great it sounds when used with a receiver that supports this feature.

I wasn’t expecting APT-X support, as it’s not that common – so this is a nice surprise for sound quality enthusiasts.

Bluetooth connectivity is reliable, by the way, and I don’t have any complaints about that itself – so nothing to worry about there.

Amplification technology used

The Kenwood KAC-M1824BT uses class D technology which is a modern super-high-speed switching approach used to increase efficiency. That’s what makes the amazingly small amp size possible.

Because of this (efficiency levels near 90%!) a class D audio amplifier uses far less electrical current and generates much less heat. Consequently, you can use smaller power wire during installation.

It’s important to understand that a poorly designed class D amp is noisy and suffers from lower sound quality. Kenwood’s design features a well-engineered approach and I’m very happy with what they’ve done.

Sound quality is very good and I definitely recommend it for all but the most demanding of listeners. But then again, if you’re installing the amp in a boat or motorcycle sound quality is something that is compromised already as listening to speakers in an open-air environment means having to deal with a lot of quality and volume loss anyway.

Overall sound quality

Kenwood’s specifications state a signal-to-noise ratio (SNR) of 90dB although the industry-certified CEA-2006 specs are rated at 74dBA. Although that may sound low, in practice the SNR ratio is measured at 1 watt/14.4V and actually greatly improves as more power is delivered.

So when you’re actually driving speakers with moderate or high volume the actual noise level will be very low – well within the 90dB SNR range.

Overall, during testing the amplifier sounds very good, I’m happy to report. Using my reference test tracks I could hear great dynamic transients and crisp, responsive sound.

I’m a big Spotify and Tidal music fan and normally listen using a higher fidelity music quality option. When used with the Kenwood amp I wasn’t disappointed and the sound I’ve become accustomed to came through loud and clear.

Image of Kenwood KAC-M1824BT amplifier in package

The amplifier is actually quite small and well-packaged. Quality is great throughout and doesn’t disappoint. I was pleased with nearly everything about it, aside from a few audio control features that I thought should have been provided (see below).

Installation and audio source functions

Switching audio sources

I like how simple it is to switch between the stereo inputs or your smart phone’s music – just push the SRC button and it switches between them.

The backlight changes to red when the RCA or speaker level inputs are in use and blue when Bluetooth is selected.


Installation is very straightforward like any standard car stereo amplifier. You’ll need to connect the +12V supply wire, remote on lead, ground wire, and RCA cables if using an aftermarket stereo.

When using speaker level inputs, there’s an added bonus: the amp features a nice auto-sensing option which means it will turn on automatically when a music signal is sensed and it won’t require you to use the remote-on wire.

The outward mounting tabs mean the amp is pretty easy to mount on a board or other suitable location (4 mounting screws are provided). Two 13.5″ wire ties also help with installation.

The wiring harness is actually fairly long, measuring about 59″ so unless you’ve got a longer reach to make that’s pretty helpful.

Kenwood KAC-M1824BT included items

Included are 2 wire ties, the wiring harness, 4 mounting screws, and a mounting base for the controller. Double-sided adhesive for surface mounting of the remote controller holder is included too.

Since it’s so small in size you can mount it in far more locations than conventional amplifiers. This is a definite plus, and for that reason, I think it’s a great choice for many.

The average person who lacks installation experience can face some hard – and discouraging – obstacles when trying to install a larger amp in tight spaces.

Why fight a battle you don’t have to?

Sound controls (and what I don’t like)

Ok, this is the one area in which I have a few complaints. Although the amp sounds great and I love the Bluetooth controller’s simplicity, you’re limited to a front/rear fader in the form of a small dial on the front of the amp.

The fader control only applies to the Bluetooth source. It doesn’t apply to the RCA input signals & speaker-level inputs.

There are no high or low-pass filters available unlike many amps available today, and that’s a shame. By eliminating this option Kenwood has restricted it to more basic setups in which full-range speakers are used.

I also noticed the amp doesn’t feature any kind of bass boost or equalization options like others, unfortunately.

Because of this, if you’re driving tweeters on are using speakers which need a high-pass filter to block low-end and distorting bass they can’t handle, you’ll have to rely on traditional passive crossovers to do so.

However, if you’re the average person just trying to get good sound to full-range speakers it’s not an issue.

Marine / environmental qualifications

The amplifier is manufactured with a conformal-coated circuit board and is suitable for not just marine applications but in any environment that may introduce dirt, moisture, salt, or other potentially corrosive substances.

But don’t worry, it’s just as home in any car or truck, too!

Note: the amp is resistant to moisture but it’s not waterproof.

USB charger port feature

The amp cannot transfer audio with the cable, but you can charge your smartphone through it as you enjoy music. Just use the 1A 5V charging jack at the end of the amp.

It’s a convenient feature that works well, but you’ll have to purchase the USB extension cord yourself.

Power ratings

Kenwood’s power ratings are accurate and confirmed, as the company is CEA-2006 amplifier compliant.

Rated power delivered is:

  • 45 watts RMS x 4 at 4 or 2 ohms
  • 90 watts RMS x 2 bridged at 4 ohms (4-ohm stable in bridged mode)

This is sufficient for average coaxial (2-way) speakers that most boats or motorcycles can use. You could use it with component speakers as well if necessary, although if you need higher performance you might want a more powerful amplifier.

Review score & summary

This is a fantastic amp and a great way to build a small system that’s affordable gives you great-sounding audio in nearly any installation.

It’s a great choice and one of the best in its class for the money. Head over now to find out why it's a best seller over at Amazon.

  • Overall quality - 9/10
  • Sound quality & performance - 8.5/10
  • Installation ease - 9/10
  • Features - 7.9/10

A compact, well-performing amp with pleasing sound quality and Bluetooth music connectivity. A great basic amplifier for boats, motorcycles, cars, or trucks.

The Kenwood KAC-1824BT is a very compact amp that is well worth the money. At only 6-11/16 x 1-13/16 x 3-7/8″ in size installation in tight spaces a breeze. Sound and performance are great, with both 45W x 4 or 90W x 2 power options. Bluetooth pairing is simple and reliable. Construction and design are good with no quality issues. Unused connectors are protected by covers included in the box.

Because of the unique design, you’re able to use the amp with only your smartphone and no stereo if desired. The intuitive remote makes controlling music apps and volume really convenient. Unfortunately, there are no crossovers or bass boost features, so the amp is best suited for full-range speaker systems – you won’t be able to drive woofers with it. Overall, it sounds wonderful and is really worth the price – a great choice for boats, outdoor vehicles, or just about any application where you want a quality basic amplifier with Bluetooth connectivity.


  • Remote is easy to use and well-labeled
  • Speaker level inputs
  • Auto-sensing if speaker inputs are used requires no remote-on wire
  • Can control music apps via Bluetooth
  • A2DP, APT-X audio quality support
  • Great overall sound!
  • Very small size
  • Supports up to 3 paired devices for Bluetooth
  • Bridgeable to 2 channels (90W x 2)
  • Quality design
  • Good signal-to-noise ratio at typical volumes
  • Conformal coating on circuit board
  • Protective covers for unused connectors to block exposure
  • Clear instructions with diagrams
  • Reliable Bluetooth connectivity
  • No apps required to use
  • Built-in USB phone charger port
  • Wired remote is simple to use & install
  • Remote has nice backlighting and good “feel” to buttons
  • Conformal coated circuit board


  • Fader dial is only applicable to Bluetooth
  • No 2/4 way “Y” switch to run all 4 channels from 2 RCA inputs
  • No high or low pass crossovers
  • No bass boost available
  • Auto-sensing for turn-on only works for speaker level inputs
  • USB charger port requires extension cable (not included)

Alpine CDE-HD149BT Full Review – A Bluetooth Car Stereo With Amazing Value And Sound

Alpine CDE-149BT front image

I’ve been an Alpine car stereo fan for years and I love using Bluetooth with my Android phone to enjoy great-sounding music and videos.

However, for many people, that require an adapter and dealing with poor sound quality.

In my full review of the Alpine CDE-HD149BT Bluetooth and HD radio head unit, I’ll show you why it’s a great buy for your money, as well as any little things you need to know.

Seriously, this thing is great!


Alpine CDE-HD149BT – basics and first impression

Over the years Alpine has produced more and more car stereos with Bluetooth, iPod, and even Pandora features built-in. However, you’re able to now enjoy all of those features and iPhone and Android smartphone capability, advanced audio controls, and superb flexibility for far less than ever before.

In the past, comparable products cost as much as several hundred dollars while the CDE-HD149BT sells for between $225 and $260 typically (prices vary widely, so see my recommendations at the end).

Alpine CDE-149BT front imageThe CDE-HD149BT is a great looking single-DIN (standard sized stereo) unit with both a tilting faceplate for loading a CD and a removable faceplate for discouraging theft of your audio investment. It’s a fun and exciting unit to use! The dot matrix display lists channels, audio source, song titles, the time and date, and so much more.

Music source features

This is a very cool head unit! Just being in front of it you feel a sense of excitement knowing how much audio control and listening advantages you have. These include:

  • Bluetooth with A2DP audio quality support and AVRCP for controlling music from the control panel
  • HD radio tuner built-in (years ago these required a separate purchase)
  • CD player
  • USB music storage support: MP3, WMA, and M4A audio files supported
  • AM/FM tuner with presets
  • SiriusXM tuner controls (add-on tuner purchase is required)
  • Pandora streaming music app remote control over your phone’s Bluetooth connection
  • Rear AUX input for all other music sources

And yes! It will charge your smartphone, too.

Don’t worry about having to manually stop the music or fumble with your phone someone call – the stereo will automatically switch over to hands-free calling when necessary and you can use the included microphone to talk. Call waiting even works, too.

Speech volume can be adjusted if you like and there are 5 sound settings to choose from to improve audio for calls.

Alpine CDE-HD149BT included hands free microphone

A microphone is included for the hands-free calling feature of the head unit. It is easy to install, and I find the mic and plug-in cord to be a pretty easy task as far as installation goes. Most of the work is simply hiding the cable once it’s connected. The clip allows good positioning on your sun visor for the best results.

Alpine’s proprietary MX setting can be enabled to improve the sound of audio depending on the audio source you’re currently listening too, including Bluetooth audio. Think of it as a “boost” feature, although I personally recommend getting much more familiar with the excellent audio controls at your service, as they allow you to tailor the sound exactly as you’d prefer rather than the fixed changes that the MX function applies.

First impressions

The unit is well-built and the rotary knob for volume and other settings feels great in the hand. The center can be pushed for additional select/menu features when applicable.

CDE-HD149BT up close image

The CDE-HD149BT is a great looking and pretty easy to use model. They’ve squeezed so much into the design that the majority of settings and initial features you’ll use (until you’re set up) are accessed through software menus.

Push the open button to release the faceplate in order to insert a CD. Pushing it back up snaps it into position again firmly and without issue. The 256 x 64 dot LCD display is clear and works great.

Text and graphics are well thought out. But in heavy sunlight, the glare can make it a little hard to see the images and readout.

Menus are fairly easy to use but you’ll definitely need to break out the instructions (I used the .pdf version from Alpine) and I recommend save the .pdf to your smartphone later use – that’s a lot easier than having to hunt for it and download on the road.

Firmware update ability

Firmware can be updated by USB easily, which is a feature I always look for. Cheaper brands don’t provide this at all. But at this level of engineering expertise, I kind of knew Alpine would provide a way to do so.

Note: I did not need to perform a firmware update before this review so I can’t report on the experience.

Audio quality features and advanced controls

Here’s one area where it really outshines the rest. The built-in audio controls and equalizer features are worlds above many others and weren’t available in car stereos of this price range in years gone by. I’m truly impressed with the level of control you have for the price. 

It’s largely thanks to the digital signal processing (DSP) design the company used to give a whole list of possibilities and 24-bit digital audio quality.

The most notable ones are:

  • Individual time correction (TCR) controls for each audio channel to adjust stereo imaging
  • High and low pass crossover filters with 0, 6, 12, and 24 dB/octave slopes and 20-200Hz frequencies
  • 6 available audio user presets so you can make and compare changes without having to worry about losing any
  • SPATIAL feature: an Alpine-only option to expand the audio listening sound space for a more realistic experience
  • Selectable volume level for each audio source (like CD, Bluetooth, and so on)

I’ve owned advanced car audio equipment for years including digital signal processors and equalizers by Alpine.

Those are units costing hundreds of dollars, some close to $800 and this is the first time I’ve seen an in-dash car stereo that nearly everyone can afford contain so much processing and adjustment power.

It’s pretty astounding and I’m sure you’ll come to appreciate as much as I have.

For decades you were stuck with some “bass and treble” level controls and little more, perhaps with a bass boost button control as well. The great news is those days are gone! The design includes 10 equalizer presets available for selection including “flat” (no effect, default setting) and works great.

Alpine CDE-HD149BT rear view
6 rear RCA jacks are available for connecting to external amplifiers for even better sound. An AUX input jack is available there as well, along with the USB cable for USB music access.

If you’re like me you don’t like being restricted to presets in order to get the best sound possible you need a true equalize to do so. You’re in luck there, too, as Alpine includes a 9-band parametric equalizer with user storage preset. And let me tell you, it’s very easy to use and works great.

If you’re not familiar with how an EQ works, it’s pretty simple so don’t worry. The parametric equalizer basically allows you to adjust a range of audio frequencies to boost or cut the level of sound in that range.

Adjustable frequency bands: (20 Hz to 20 kHz)

Band 1: 20 Hz ~ 100 Hz (63 Hz)
Band 2: 63 Hz ~ 315 Hz (125 Hz)
Band 3: 125 Hz ~ 500Hz (250 Hz)
Band 4: 250 Hz ~ 1 kHz (500 Hz)
Band 5: 500 Hz ~ 2 kHz (1 kHz)
Band 6: 1 kHz ~ 4 kHz (2 kHz)
Band 7: 2 kHz ~ 7.2 kHz (4 kHz)
Band 8: 5.8 kHz ~ 12 kHz (8 kHz)
Band 9: 9 kHz ~ 20 kHz (16 kHz)

And it even has an adjustable bandwidth (called “Q”) too!

Subwoofer controls

As the unit has 6 available RCA outputs to connect to external amplifiers (front, rear, and subwoofer) it’s helpful to know that the subwoofer output is independently adjustable (including on/off) so you won’t need any additional components to do so if adding a subwoofer to your system.

AMAZING smartphone audio control

One thing that really blew me away was being able to control the stereo from my Android phone after installing the Alpine TuneIt app which is also available for iPhone too.

Alpine CDE-HD149BT phone app screenshots

With the app, you have the ability to wirelessly control the equalizer, time correction, EQ presets, and all major built-in advanced audio controls. Unfortunately, while the app generally works well it seems like it’s a bit “quirky” at times and still leaves room for improvement.

With the level of quality you get in the head unit itself, I would have expected better from Alpine, but it’s a relatively minor complaint.

I imagine it is likely due to them using a 3rd party app developer without sufficient testing and debugging before release (just my guess).

Quick note: My observations seem to reflect reviews on the Google App Store: some users have posted complaint reviews describing issues with the app during use. The app is convenient and not at all necessary for the features, so while it would be great to be better it’s not a big issue.

Pandora controls

Connected via USB or over Bluetooth, you may control your Pandora music app using the faceplate controls for added convenience instead of having to pick up and touch your phone while driving. You can even use the Thumbs Up & Down buttons!

Alpine Pandora badge

One really cool feature I like (as I’m a Pandora user, too) is being able to add a Pandora station and bookmark it for calling back later.

Faceplate color customization

Another great feature is the ability to change the faceplate’s button backlighting. Selectable colors are blue, green, red, and amber to match most vehicle interiors at night.

Steering wheel interface capable

Not surprisingly the stereo can also be controlled with your car’s factory steering wheel controls. That requires an aftermarket adapter and there may be some limitations to which buttons will work with the control interface, so be aware of that ahead of time.

Normally the basic controls will work but a few may be lost when changing from the factory to an aftermarket stereo when installing the steering wheel interface adapter. (This isn’t the fault of Alpine – companies like PAC who make these specialty adapters have to work around limitations of the vehicle)

iPod controls

Nearly all major iPods and iPhones are supported via the USB connection, but a USB adapter is required for that (KUC-445i) so you’ll have to spring for more money if not using Bluetooth and want to use the built-in iPod controls.

The KCU-445i must be purchased separately if you’d like to use a plug-in iPod or iPhone control. It sells for close to $25 or so. But it’s not necessary if you’re using a Bluetooth iPhone.

Note: I do not own an iPhone or iPod so unfortunately I couldn’t test those as well. However, I’ve heard good things, aside from minor complaints.

iTunes tagging feature

When you hear a song you like, simply press and hold down the CDE-HD149BT’s Volume button for two seconds. The tagging feature lets you tag songs you hear on SiriusXM and stores the info on your iPhone. The next time you connect your iPhone to iTunes, you can be able to preview your selections and then buy/download them directly from iTunes.

GameAlert for sports fans

Want to know if your favorite sports team is playing live but want to keep enjoying other music in the meantime? The CDE-HD149BT has GameAlert that will display an on-screen message if your favorite teams’ games are being broadcast.

You can then jump to that station with the push of a button so you can listen to the game. It’s a cool feature even though I’m not a sports fan, personally.

Sound quality

Alpine CDE-HD149BT installed in dash

I’m sure your next question is “But how’s the sound?” The answer is…great!

The audio is crisp and clear thanks to the digital signal processing when using the internal amplifiers, although just like other head units you’re limited to 18 watts per channel at 4 ohms.

I would have liked some type of higher power Class D amplifier but perhaps there’s simply not room after packing so much into it already.

Like most stereos, the CDE-HD149BT is good for casual everyday listening and some high-volume listening, but as expected it can’t drive woofers or components speakers (especially with heavy bass music) too hard without beginning to distort from a lack of sufficient amplifier power.

For a great, low noise output signal the RCA connections can provide up to 4V of line-level audio.

If you need higher power I definitely recommend taking advantage of the RCA outputs, and you’ll actually be able to get even cleaner sound! A great amplifier I can suggest is the MRV-F300 that I wrote about here.

Anti-theft features

Alpine CDE-HD149BT anti-theft faceplate imageThe detachable faceplate actually swings down when released for inserting a CD. But it also easily detaches and can be re-inserted when you leave your vehicle unattended and is stored safely in the included protective case.

What’s included?

Alpine CDE-HD149BT box and accessories included imageThe box includes the standard basic items for a single DIN size Alpine car stereo, plus a few additional items you can use right away.

These include:

  • Plastic protective case for the detachable faceplate
  • Removal keys for the locking installation sleeve
  • Hands free microphone with visor clip, double-sided tape, and cable
  • Power and speaker output wiring harness
  • USB female extension cable (for using a flash drive)

I definitely recommend planning before installing it in case you’ll need additional cable extensions or speaker wire. You may also need the right vehicle harness adapter and installation kit. (My advice is to check out Amazon because small car stereo shops make a lot of money off of items like this, plus you won’t have to spend a whole day searching this way).

Final thoughts & review score

All in all, this is hands down one the best car stereos under $300 you’ll find anywhere, and it’s a great value for what you get.

Bluetooth connects and stays connected reliably and quickly, too. It’s capable of remembering the last device it paired with (your phone) which means it won’t attempt to connect to nearby devices while you’re trying to do the same already.

If you’re looking for great features and excellent sound from your phone via Bluetooth (or many other sources!) don’t hesitate to check it out!

Head over to see the latest low price and get free shipping from Amazon.

  • Overall quality - 9.5/10
  • Performance/Sound Quality - 8.5/10
  • Installation ease - 9/10
  • Features - 9.5/10
  • Value - 9.8/10

An amazing amount of technology and control for its price. Wonderful Bluetooth sound quality and surprising audio controls

The Alpine CDE-HD149BT is a VERY impressive car stereo with some of the best features money can buy. Featuring digital processing technology, A2DP Bluetooth audio support, and both iPhone and Android compatibility it has something for everyone. With an advanced audio equalizer, crossover, and time correction controls it can satisfy even the most advanced music listener. If you love a good value and want great Bluetooth performance you’d have to be crazy to pass up such a great choice.


  • Great sound and clear audio
  • A2DP Bluetooth support for great sound quality
  • Pandora control functionality
  • Facebook notification support
  • 9-band EQ with user presets
  • 10 selectable factory audio EQ settings
  • Detachable faceplate and storage case
  • AUX input
  • USB flash drive support
  • iPod support (with required cable)
  • 4 selectable illum. colors
  • 6 RCA outputs: 4 front/rear, 2 dedicated subwoofer
  • Can connect to steering wheel control adapter
  • iPhone & Android app wireless audio adjustment
  • Hands free call feature
  • Auto-answer & phone book features
  • iPod & iPhone plug-in control possible
  • CD/FM/AM/HD radio built in
  • SiriusXM ready (requires tuner)
  • Subwoofer output level/phase/type controls
  • Rotary control knob
  • Firmware update cable via USB
  • USB supports MP3/WMA/M4A
  • Time and date
  • 6 presets for storing user custom audio adjustments


  • Limited internal amp power (18W channel/4 ohm stable)
  • Push-button remote is separate
  • AUX input is located on the rear-requires extension cable
  • iPod plug-in support cable is separate
  • Music app control is limited to Pandora
  • No digital audio output (TOSLINK)