Amplifiers are the heart of your boat's stereo. They obviously pump power to ever corner of your boat, but they also are typically the bottleneck if you don't align them well with your system and your personal goals for your stereo. You could have the absolute best speakers, subwoofers and head unit on the market with the latest tech and best reviews but without proper amplification that all goes to waste. And quality doesn't just mean clarity in a marine application, it means dependability and longevity too. Something that is a consideration when you're building a stereo for your vehicle, but not necessarily a pivotal factor like it is when you're looking for an amplifier for your boat.

Typically, boat amplifiers are tucked in tight quarters. They're in lockers or compartments under your dash. Combined with a hot summer day, extended periods of music playing at high volume, moisture (and maybe even some splashes of water) – repeat. It used to be a recipe for disaster. Amplifiers would sabotage themselves in the confined quarters where heat was excessive. They'd overheat or worse if there wasn't any failsafe features. And there's never a good time for an amplifier to fail when you're out on the water. This is exactly why amplifiers were designed for marine applications. They're more efficient today, they run cooler and for longer and are made with anti corrosive materials like stainless steel and gold plating. They may have a higher price tag than some of their automotive cousins but it's the marine-specific features that'll bring you long-term and dependable stereos on your boat, season after season.

The KXM amplifier has been around for a good while now. In 2018, they updated the platform to the most current version of the KXM series amps with a ton of great features that make music great on the water, and also tuning easy for the DIYer. They look great too – the current amps are blacked out now (prior to 2018 they had a stainless/silver finish. And they're compact for tight quarters.

We recently installed a pair of KXMA8005s in a 25ft lighting speedboat (full installation here) to power 8 speakers and two subwoofers. In this review we'll walk you through our experience with the amps and review the features we liked.

Unboxing the KXM Amplifier

We were pretty excited to check out our amplifiers when we received them. The packaging looked great and felt super solid. And when we opened up the box they didn't spare any expense on an enormous, shiny Livin' Loud Performance certificate.

First impressions were good overall. What stood out to us immediately was really the size of the amp. They're pretty compact and they're light weight (but not too light weight). The amp itself was sealed in a separate wrapping and the kicker emblem protected with a transparent removable film. The black look with stainless hardware – screws, terminals, etc – really pop and in general it passes the look and feel test. In the box, we found:

  • KXM amplifier (obviously)
  • KXARC wireless remote control
    • Surface mount cup
    • Bezel
    • 2 Mounting brackets
  • 2 Self-tapping screws (length 1″)
  • 4 Self-tapping screws (length 2″)
  • 4 Flat washers
  • 3mm Allen wrench
  • Owner's Manual
  • Kicker Livin' Loud Performance certificate

KXM Amplifier Series Feature Overview

Let's dig into some of the core features of the KXM Series Marine Amplifiers, and some of the things that we thought make it stand out.

Marine grade

Right from the get-go, you can tell these amps aren't just another automotive amp with stainless steel screws. Kicker incorporates a number of features that make them marine worthy – both visible from the outside and deep within.

Starting with the inside, they've conformal-coated the entire circuit board. Conformal coating is basically a thin polymeric film that conforms to the contours of a circuit board to protect it from water, dust and corrosion in general. The cover is sealed with a gasket too to prevent as much moisture and water from penetrating the inside as possible. On the outside, they've used corrosive-resistant power connections and terminals and of course stainless steel hardware – both to hold the amplifier together and separate stainless hardware to mount it to your surface in your boat to prevent rust. Like their KM speakers and KMF subwoofers, the KXM amps just look and feel pretty well ‘sealed' from the elements which will help to keep your music loud for seasons to come.

Unique Bluetooth Wireless Remote – KXARC

One of the cool, stand out features that we were excited to tinker with on these amplifiers were the wireless remotes. They're really cool! They're bluetooth wireless – long gone are the days where you had to wire a volume knob via an eithernet-looking cable to the back of your amplifier to control the gain. From the cockpit of your boat, you can adjust the sub level, the sub's phase, and even get some warning when your subs are clipping.

And since they're Bluetooth, if you have more than one amplifier you can hook multiple amps up to one remote. In our setup, we had two of the KXMA800.5s with one sub hooked up to each. It works perfectly to control the gains for both subwoofers with one remote even though they were hooked up to separate amps. The connection is SUPER easy too. You simply click a small pairing button on the amplifier to put the amplifier in pairing mode and the pairing light will begin to blink. Then, click the pairing button on the remote and they'll sync within seconds and the amplifier pairing light will go solid. To add other amplifiers, simply click the pairing button on the next amplifier immediately after you paired your first amplifier and they'll all sync to one control.

The only thing that we noticed about them, not necessarily a bad thing though, was the size of them. But they're stylish enough to feature as a part of your dash so you may actually like the size. They come with a mounting bracket and a bezel to fit snug into a cutout in your dash. Or, if you want to throw it into a cubby or compartment you can do that too since it's wireless!

Tuning Made Easy

This was honestly the first amplifier that we've personally tested with a built-in illuminating gain feature that actually helps you set your gains. It's really easy, and really effective. It makes our quick guide to tuning an amplifier even quicker. You simply turn up your head unit volume to about 3/4 and begin turning up the amplifier gains until the translucent red gain control until they start blinking red. Then you back them off a little until it goes off. Done.

KXMA8005 control panel
Closeup of the KXMA800.5 control panel with lightup gains

Kicker also posted a good walkthrough of how to tune their KXMA amps which also applies to the KXM amps as well. It walks through the illuminating gain lights and how to match your gains to your head unit.

In addition to the useful gain illumination feature, the KXM amps have all of the rest of the normal tuning features built into the tuning panel – HP/LP/Full with frequency range tuning, etc. Couple cool things to call out though that make these amps a little more flexible than most amplifiers:

Fader Switch: If you're running only one set of inputs for the whole amplifier you can switch this to ON and it will take the signal and apply it for all channels. When we installed two of the 800.5 amps, we had one for the front four speakers on our boat and one for the rear four speakers and only had one input for each amplifier. We used this feature. But for those who are going to run front and rear signal wire, it wouldn't be used.

Sub Input: If you're only running front and rear signal wire (or only one or the other), and won't be running a separate sub input, you can use this input button switched to OFF and your amplifier will run the subwoofers from the other inputs. Combine this with the Fader switch and you really only need to run one RCA signal wire to power all channels of this amplifier. We also used this feature in our installation, as we only ran one RCA to each of our two amps.

Adjustable Subsonic Filter: If you want to protect your subs from damage, you can set the subsonic filter to cut out the lowest frequencies and prevent your speakers from over-excursion. It'll also reduce the amount of wasted power your amplifiers are sending to your subs.

KickEQ Bass Boost Control: Many subwoofer amplifiers have bass boost. But what's different about Kicker's bass boost is that it can be used in combination with the illuminating gain feature to further tune your subwoofers. You can fully optimize your sub output between the gain control, subsonic filter and this bass boost control.

Radio Detect: Some head units may not detect the system and as a result won't play audio out of one or more of the speakers in the system. With Radio Detect, the amplifier will always tell the head unit that the speakers are present.

Amplifier Specs

Because what would a review be without them?

 ChannelsRMS Power HandlingFrequency Response ± 1dBInput SensitivitySignal to Noise Ratio (dB)
KXMA 400.22@ 14.4V, 4Ω stereo, ≤ 1% THD+N : 100 x 2
@ 14.4V, 2Ω stereo, ≤ 1% THD+N : 200 x 2
@ 14.4V, 4Ω bridged mono, ≤ 1% THD+N: 400 x 1
10Hz–20kHz250mV-10V95
KXMA 400.44@ 14.4V, 4Ω stereo, ≤ 1% THD+N: 50 x 4
@ 14.4V, 2Ω stereo, ≤ 1% THD+N: 100 x 4
@ 14.4V, 4Ω bridged mono, ≤ 1% THD+N: 200 x 2
10Hz–20kHz250mV-10V95
KXMA 800.55@ 14.4V, 4Ω stereo, ≤ 1% THD+N: 50 x 4
@ 14.4V, 2Ω stereo, ≤ 1% THD+N: 100 x 4
@ 14.4V, 4Ω bridged mono, ≤ 1% THD+N: 200 x 2

SUB:
@ 14.4V, 4Ω mono, ≤ 1.5% THD+N: 200 x 1
@ 14.4V, 2Ω mono, ≤ 1.5% THD+N: 400 x 1
@ 14.4V, 1Ω mono, ≤ 1% THD+N : +/- 10%
AMPS 1 - 2: 10Hz–20kHz
SUB: 10Hz-160Hz
250mV-10V95
KXMA 800.88@ 14.4V, 4Ω stereo, ≤ 1% THD+N: 50 x 8
@ 14.4V, 2Ω stereo, ≤ 1% THD+N: 100 x 8
@ 14.4V, 4Ω bridged mono, ≤ 1% THD+N: 200 x 4
10Hz–20kHz250mV-10V95
KXMA 1200.11@ 14.4V, 4Ω mono, ≤ 1% THD+N : 600 x 1
@ 14.4V, 2Ω mono, ≤ 1% THD+N : 1200 x 1
@ 14.4V, 1Ω mono, ≤ 1% THD+N : +/- 10%
10Hz–160Hz250mV-10V95
KXMA 1200.22@ 14.4V, 4Ω stereo, ≤ 1% THD+N : 300 x 2
@ 14.4V, 2Ω stereo, ≤ 1% THD+N : 600 x 2
10Hz–20kHz250mV-10V95

Summary & Final Thoughts

Like much of their other marine products, we really loved these amplifiers. They're perfectly matched with their speakers and subs and have all of the features that you want and need in an amp. Their blacked out and compact design looks great, and allows them fit in tight spaces too.

When you combine the Fader Switch and Sub Input with the many bridging options, their amps (like the KXMA800.5) are also incredibly versatile and flexible for almost any application and combination of speakers. They really thought through things like:

  1. Replacing or upgrading amplifiers with existing wiring. Thus the fader and sub inputs.
  2. Tuning for first timers. Yes there's still a lot of knobs and buttons on the amplifiers, and there should be. But for first-timers, I don't think it gets better than this. It's a great amplifier to learn how to tune on and figure out where you cross the line with gains.
  3. Marine application. Obviously they took many steps to prevent failure due to the elements with features like the conformal coating.

What Makes Them Different

In terms of some of the features that we really liked and thought made these amplifiers stand out from others:

  • Illuminating Gain control. We've never actually tuned an amplifier with this feature before, but loved it. It's as simple as it sounds – too much gain, the light turns on. Back it off until the light goes off again.
  • Bluetooth KXARC Remote. This was awesome too. Pair one controller to multiple amplifiers wirelessly and mount it wherever you want. It allows you to set the gain, change the subwoofer phase, check for clipping and more all from one Bluetooth remote.