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

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)

About the author

Marty is an experienced electrical, electronics, and embedded firmware design engineer passionate about audio and DIY. He worked professionally as an MECP-certified mobile installer for years before moving into the engineering field. Read more »

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