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Kicker 40KX800.5

5-channel car amplifier — 50 watts RMS x 4 at 4 ohms + 400 watts RMS x 1 at 2 ohms

Item #: 2064KX8K5

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4 Reviews | 3 questions - 3 answers

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Delivers dependable power to your whole system with style

Kicker designed the KX800.5 5-channel amplifier to run your entire system, powering four speakers with 50 watts RMS each while driving a sub with up to 400 watts RMS. This reliable and compact KX Series rocker remains cool even when pushed hard, thanks to its high-mass heatsink, high-tech internal components, and efficient full-range Class-D amp technology. Not worried about rear speakers? You could also use this amp in 3-channel mode to send 200 watts RMS each to some high-performance components up front, and still run your sub with 400 watts.

Connects to virtually any system

Kicker employs their Fail-Safe Integration Technology (FIT™) to reject noise and stop any interference generated by your car's electronics, so you'll enjoy your music clean and pure. Speaker-level inputs make it possible to hook this amp up to almost any stereo, even a factory system. Kicker even thought to build in a 3-second turn-on delay, eliminating any annoying and potentially damaging turn-on pops.

Versatile controls behind the folding door

A folding door with magnetic latches gives you quick and easy access to your amp's controls. You can tune for almost any kind of speaker, as the steeply-sloped high- and low-pass filters offer a wide range of adjustment. The filter section for the rear channels can be set up for bandpass operation — where both the high- and low-pass filters are engaged to allow only the frequencies between them to play — for optimizing the signal for midbass drivers or other component speakers. The subwoofer channel includes a bass boost for adding some kick to your music, along with a subsonic filter that eliminates the extra-low, inaudible frequencies that only waste your sub's energy.

Kicker KX800.5 control panel

                                                                             KX800.5 control panel

Product Highlights:

  • 5-channel car amplifier
  • 50 watts RMS x 4 + 200 watts RMS x 1 at 4 ohms
  • 100 watts RMS x 4 + 400 watts RMS x 1 at 2 ohms
  • 200 watts RMS x 2 bridged at 4 ohms + 400 watts RMS x 1 at 2 ohms
  • CEA-2006 compliant
  • variable high- and low-pass filters (10-5000 Hz, 24 dB/octave) on front channels
  • variable high-pass (10-500 Hz, 24 dB/octave), low-pass (10-5000 Hz, 24 dB/octave), and bandpass (10-5000 Hz, 24 dB/octave) filters on rear channels
  • variable low-pass (40-160 Hz, 24 dB/octave) and subsonic (10-80 Hz, 24 dB/octave) filters on subwoofer channel
  • variable bass boost (0-18 dB at 40 Hz) on subwoofer channel
  • front-mounted controls protected behind fold-down door with magnetic latches
  • wired remote bass level included
  • Class D amp technology
  • Fail-Safe Integration Technology eliminates noise from your vehicle's electrical system
  • preamp and speaker-level inputs (speaker wire to RCA adapter required for speaker-level input)
  • 4-gauge power and ground leads and a 100-amp fuse recommended — wiring and hardware not included with amplifier
  • no onboard fuses — when installing multiple amplifiers in a system, an additional 100-amp in-line fuse between the distribution block and this amplifier is recommended
  • 12-3/4"W x 2-3/16"H x 8-3/4"D
  • warranty: 2 years (extends to 3 years when purchased with either a Kicker single amp wiring kit or a Kicker multi-amp kit)
  • Our 60-day money-back guarantee

My system has plenty of power. Who needs an amp?

You might think you don't need an amp because you have a 400-watt system in your car, or because your new stereo puts out 50 watts a channel. But those are peak wattage ratings, which may boil down to 15 or 20 watts per channel, using the more realistic RMS rating. An amp sends your speakers the power they need to deliver your music with clarity and impact, whether you're using factory speakers or high-performance components. And low-frequency reproduction requires lots of power, so an amp is an absolute must if you're adding a sub to your system.

Kicker 40KX800.5 Reviews

Average Customer Review:

4 Reviews

All I can say is, WOW

Written by: Toughsox from New Jersey on January 8, 2016

Crutchfield Customer Review (What's this?)

I outfitted my new Z71 Colorado with this is the anchor point. My product advisor at Crutchfield made the recommendation and he hit the nail right on the head.

Pros: The sound before and after is more than I thought was possible.....simply amazing. I have a 4 door with minimal room behind the rear folding seats but, this fit behind them like a glove.

Cons: None


Written by: Darrin M from Tallahassee fl on December 20, 2015

Crutchfield Customer Review (What's this?)

Just the perfect size.this amp does it all.and it really KICKS out the jams.very underrated.worth every dollar.

Pros: Size Wattage

Cons: Can see the fold down door getting loose after years.

good amp for those seeking BASE

Written by: Alex from Coral Springs, FL on October 27, 2014

Crutchfield Customer Review (What's this?)

A nice amp that delivers great value for the money.

Pros: Compact Lid allows for easy access to controls Great power delivery (if that's what you're looking for) Allows for one amp to drive both speakers and Sub

Cons: Still too large to fit under the seat of a small car (e.g., Mini Cooper) Dynamic range is still not as good as it's competition (e.g., Alpine PDR-V75 75W x 4 + 250W x 1)

Awesome amp

Written by: Anonymous from Redding, Ca on July 5, 2014

Crutchfield Customer Review (What's this?)

This amp works great and actually puts out more wattage than stated. Nice clean sound.



Hands-on research

What's in the box?

Download owner's manual

  • 5-Channel amplifier
  • Remote bass-level control knob
  • 20' Remote cable (with an RJ-25 phone plug on each end)
  • Four 2" Self-tapping screws
  • 4 Flat washers
  • 3mm Allen wrench
  • Owner's Manual (English/ French/ Spanish/ German)
  • Power certificate

Product Research



Class D Amplifier Design: The Kicker KX800.5 is a Class D amplifier with four full range channels and a single subwoofer channel. It uses a digital switching power supply, resulting in high efficiency and less heat. The Class D design also allows the KX800.5 to have a small footprint for increased cargo space.

CEA-2006 Compliant: CEA-2006 is a system of testing and measurement methods for mobile audio amplifiers. This voluntary standard advocates a uniform method for measuring an amplifier's RMS power output and signal-to-noise ratio. The criteria for measuring power uses a DC input voltage of 14.4 volts and the RMS power output is measured into a 4Ω load, with 1% or less Total Harmonic Distortion plus noise (THD+N), and over a frequency range of 20 Hz to 20 kHz (for full range amplifiers). Signal-to-Noise ratio is measured in weighted absolute decibels (dBA) at a reference of 1 watt into 4Ω. CEA-2006 allows consumers to compare car amplifiers and receivers on an equal basis. Using CEA-2006 criteria, the Kicker KX800.5 is rated at 50 Watts RMS x 4 channels plus 200 Watts RMS x 1 channel with a 75 dBA signal to noise ratio.

Specifications: The manual also lists these non CEA-2006 compliant specifications:

  • Power (full range):
    • 2Ω: 100 watts x 4 channels (no more than 1% THD+N, 14.4 volts)
    • Bridged: 200 watts x 2 channels (into 4Ω with no more than 1% THD, 14.4 volts)
  • Power (subwoofer): 400 watts x 1 channel (into 2Ω with no more than 1% THD, 14.4 volts)
  • Signal to Noise Ratio: 95 dB (at rated power)

Kicker Livin' Loud Certified Power: The amplifier comes with a certificate that indicates the total maximum RMS power output of the particular amplifier, along with the model number, serial number, and whether the amplifier passed the total harmonic distortion, signal-to-noise ratio, and protection circuit tests.

Auto Turn-On: The Auto Turn-On switch offers three options:

  • +12 V: The amp turns on when +12 volts is applied to the remote terminal.
  • DC Offset: The amp turns on when a 6 volt offset is detected on the signal inputs (from a speaker-level source); in this mode the amp's remote terminal acts as a +12 volt output to turn on another component.
  • Audio: The amp turns on when an incoming audio signal is detected; in this mode the amp's remote terminal acts as a +12 volt output to turn on another component.

Subsonic Filter: The subwoofer amp also features a 24 dB/octave subsonic filter, continuously variable from 10 Hz to 80 Hz. Ultra-low frequencies that cannot be reproduced by a subwoofer do not become sound, but unnecessary oscillations, which affect sound by causing distortion. These frequencies also waste amplifier power and can cause damage to speakers. The built-in subsonic filter removes the signal below the set frequency to improve the performance of the speakers by eliminating harmful distortion. The subsonic filter crossover cannot by bypassed.

Protection Circuitry: The KX800.5 has protection circuitry that will turn the amp off in the event of overheating, over voltage (power input), under voltage (power input), short circuit (speaker output), and over current (speaker output). If the Protection LED on the front side of the amp illuminates red, the protection circuit has engaged and the amp will not play until the problem is resolved.


Gain: To accommodate the varying range of signal levels coming from today's factory and aftermarket radios, the Kicker KX800.5 features adjustable gain controls (low level: 125mV-5V, high level: 250mV-10V). The front, rear, and subwoofer sections of the amplifier (Amp 1, Amp 2, and Sub) have independent rotary gain controls, labeled from 0 to 11.

Input Level Switch: Set the input level switch to low when using preamp level input signals and high when using speaker level input signals.

Crossover: The front, rear, and Subwoofer sections of the amplifier also have independent crossover circuits:

  • Amp 1:
    • Mode: three position switch; Off (crossover bypassed), HP (high-pass), or LP (low-pass)
    • Range: two position switch; sets the frequency adjustment range for the crossover point dial; 1x (10-500 Hz) or 10x (100-5,000 Hz)
    • Frequency: continuously variable from 10 to 500 Hz (with Range switch in the 1x position) or 100-5,000 Hz (with Range switch in the 10x position)
  • Amp 2:
    • Mode: four position switch; Off (crossover bypassed), HP (high-pass), LP (low-pass), or BP (band-pass, both high-pass and low-pass circuits engaged)
    • Range: two position switch; sets the frequency adjustment range for the low-pass crossover point dial; 1x or 10x
    • High-Pass Frequency: continuously variable from 10 to 500 Hz
    • Low-Pass Frequency: continuously variable from 40 to 500 Hz (with Range switch in the 1x position) or 400-5,000 Hz (with Range switch in the 10x position)
  • Sub:
    • Subsonic: high-pass; rotary control, continuously variable from 10 Hz to 80 Hz
    • Low-Pass Frequency: continuously variable from 40 to 160 Hz

KickEQ: The subwoofer section's KickEQ bass boost circuit is continuously variable from 0 to +18 dB and centered at 40 Hz. The front and rear amps do not have bass boost circuits.

Fader: When your source unit has discrete front and rear outputs, set the fader switch to on. Turn the fader switch off to send a single stereo input to both the front and rear amps.

Sub Input: If your source unit has a discrete subwoofer output, set this switch to Sub. Otherwise set to Amp 2, and the subwoofer amp will receive its signal from the same source as Amp 2.

KXRC Remote Bass Control: The KX800.5 comes with the KXRC Remote Bass Control, which allows you to control the output level of the subwoofer amplifier from the front of your vehicle. The wired remote can be mounted under your dash. The supplied 20' cable, with RJ-25 phone plugs at each end, connects the wired remote to the amplifier.

Note: The KXRC Remote Bass Control measures approximately 1-5/8" wide x 1" high x 1-1/4" deep (2-1/8" including knob and cable).


Power Connections: The power and ground connections are set-screw terminals that will accommodate up to 4-gauge wire. The remote turn-on set-screw terminal will accept up to 8-gauge wire. The included Allen-wrench is required to loosen/tighten the terminals.

Note: The Amplifier is not equipped with an internal fuse. An external 100-amp fuse (not included) must be installed on the power wire. If the system has only this amp and a wiring kit is used that includes a fuse with a value other than 100-amps, the original should be replaced with a 100-amp fuse.

Speaker Outputs: The Kicker KX800.5 is equipped with five pair of set-screw terminals (left and right for Amp 1 and Amp 2, and a single subwoofer output). The terminals will accommodate up to 8-gauge wire and are loosened/tightened with the included Allen-wrench.

Dual Sensitivity Inputs: The KX800.5 has three sets of dual sensitivity differential RCA inputs (Amp 1, Amp 2, and Sub). They will accept either speaker-level (high) or RCA (low) signals from your car's head unit. A high-level signal can be run from the head unit's speaker outputs to the stereo RCA inputs of the amplifier using Speaker Wire to RCA adapters (206KiSL, sold separately). The Input Level Switch on the amp should be set to high when using a speaker-level input, and low when using an RCA line-level input.

Remote Bass: Connect the included wired remote bass control to the RJ-25 port on the amplifier.

Our Product Research Team

At Crutchfield, you'll get detailed, accurate information that's hard to find elsewhere. That's because we have our own in-house Product Research team. They verify what’s in the box, check the owner's manual, and record dimensions, features and specs. We stay on top of new products and technologies to help people make informed choices.

Customer Q&A

Crutchfield asked  
Why did you buy this?

I love kicker amps [ DARRIN L  Dec 07, 2015 ]

3 questions already asked

The Kicker KX800.5 is a Class D amplifier that uses a digital switching power supply, resulting in high efficiency and less heat than traditional Class AB amps. However, to ensure optimal performance from the amplifier, it'd be ideal if it received some air flow when installing it into a tight/enclosed space. [ Larry  Nov 30, 2015 ]  Staff
I believe so but not sure I think you have to bridge you sub port. I have all 4ohm speakers. I also re wired all my speakers not using and of the factory. If looking to buy also buy a compassitor [ DEREK R  Feb 06, 2015 ]
Thanks for your question. For information on selecting the best amp for your subs I would recommend reaching out to an Advisor by phone (1-800-324-9695) or online chat. They will be able to help determine the differences between the amp models and help you make the best choice for your system. [ Krissy  Dec 30, 2014 ]  Staff