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Power for your speakers

Kicker's CX300.4 4-channel amplifier delivers 40 watts RMS to each of your front and rear speakers, or you can drive a couple of subs with up to 150 watts RMS each in 2-channel mode. And they don't cut any corners building this amp, using oversized transistors, special transformers, and a heavy-duty heat sink to bring you reliable power that won't fade when you push your system hard. Built-in high- and low-pass filters help you sculpt the sound to get the most out of your system, while variable bass boosts allow you to add some low-end punch to your front and rear channels separately.

Vertical mounting

Kicker includes hardware for vertical mounting.

Hooks in almost anywhere in almost any position

Kicker uses their Fail-Safe Integration Technology (FIT™) to keep this amp's input free from noise or interference, so you'll get a clean signal from almost any system, even a factory radio. Rugged metal end panels provide even more shielding from radiated interference. The CX300.4 also comes with hardware that lets you you mount it vertically, so you can put it in a location that takes up very little floor space and looks ultra-cool.

Product Highlights:

  • 4-channel car amplifier
  • 40 watts RMS x 4 at 4 ohms (75 watts RMS x 4 at 2 ohms)
  • 150 watts RMS x 2 at 4 ohms (4-ohm stable in bridged mode)
  • CEA-2006 compliant
  • Class AB amp technology
  • separate variable high- and low-pass filters (50-200 Hz, 12 dB/octave) for front and rear channels
  • separate variable bass boosts (0-12 dB at 40 Hz) for front and rear channels
  • frequency response: 10-20K Hz
  • preamp and speaker-level inputs (optional wire adapter required for speaker-level inputs)
  • balanced differential inputs and Fail-Safe Integration Technology eliminate noise from your vehicle's electrical system
  • 8-gauge power and ground leads and a 60-amp fuse recommended — wiring and hardware not included with amplifier
  • no onboard fuses — when installing multiple amps in a system, an additional 60-amp in-line fuse between the distribution block and the amplifier is recommended
  • includes hardware for vertical mounting
  • 13-1/4"W x 2-3/8"H x 7-1/8"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 12CX300.4 Reviews

Average Customer Review:

4 Reviews


Written by: MICHAEL C. from WASHINGTON on December 7, 2015

Crutchfield Customer Review (What's this?)



Cons: NONE

Kicker 12CX300.4 Amp

Written by: Travis from Illinois on October 14, 2015

Crutchfield Customer Review (What's this?)

This amp was a breeze to install and I am all about doing it myself. I had been running stock speakers on a aftermarket deck for a while and just couldn't get the sound out f them to match up with my subs. After purchasing 4 new kicker 6x9 speakers and this amp all I can say is WOW, have I been missing out! Honestly I really didn't think it would be that big of a difference but boy did it ever. This amp has plenty of power and sounds excellent!

Pros: Easy to mount and easy to hook up and install!

Cons: Positive power terminal and Negative Power terminal could be larger.

great sound

Written by: south texas tuning from corpus christi, tx on August 12, 2013

Crutchfield Customer Review (What's this?)

Easy installation great product


Cons: Big

Kicker amp

Written by: Dennis from Holtsville ny on July 14, 2013

Crutchfield Customer Review (What's this?)

I had this kicker amp installed in my 71 Camaro and it sounds great. With dual exhausts it hard to hear the radio but with this amp it really makes the speakers roar.

Pros: Easy to install

Cons: None

Hands-on research

What's in the box?

Download owner's manual

  • 4-Channel amplifier
  • 2 Vertical mounting brackets
  • Four 3/4" Self-tapping screws
  • Owner's manual (English/ Spanish/ German/ French)
  • Power certification sheet

Product Research



CEA 2006 Compliant: The Kicker CX300.4's power ratings are measured under conditions approved by the Consumer Electronics Association (CEA). These standards allow you to accurately compare the rated power output of all CEA 2006-compliant amplifiers, even from different brands. Manufacturers who adhere to the standards can display the CEA 2006 logo on their products and packaging.

Kicker Livin' Loud Certified Power: The amplifier comes with a certificate that indicates the total maximum wattage 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 amp offers two automatic turn-on modes:

  • +12V: connect a wire from the remote turn-on lead from your source unit to the REM terminal on the amplifier; this is the preferred turn-on method
  • DC Offset: turns the amp on when a 6-volt DC offset is detected at the high-level speaker inputs when the source unit is turned on

Vertical Mounting: The amp can be mounted vertically using the included brackets. The vertical dimensions are approximately:

  • Width: 13-1/4"
  • Height: 7-1/4"
  • Depth: 2-3/8"

Signal to Noise Ratio: The S/N under CEA-2006 compliant conditions (1 watt output) is 75 dBA. The S/N at rated power is 95 dB.


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

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.

Gain: The front and rear sections of the amplifier (Amp1 and Amp2) have independent rotary gain controls, continuously variable from 125 mV to 5 V when the Input Level switch is set to Low and 250 mV to 10 V when the Input Level switch is set to High.

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

  • Mode: three position switch; Off (crossover bypassed), Hi (high-pass), an Lo (low-pass)
  • Frequency: continuously variable from 50 to 200 Hz; the slope is 12 dB per octave

Bass Boost: The bass boost circuit is continuously variable from 0 to +12 dB and centered at 40 Hz. The front and rear amps have separate bass boost controls.


Left Side of Amplifier:

  • +12V (power): terminal strip; accepts spade connectors up to 0.5" wide
  • REM (remote turn-on): terminal strip; accepts spade connectors up to 0.325" wide
  • GND (ground): terminal strip; accepts spade connectors up to 0.5" wide
  • Speaker Outputs: terminal strip with four pair of outputs; accepts spade connectors up to 0.325" wide
Note: The Amplifier is not equipped with an internal fuse. An external 60-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 60-amps, the original should be replaced with a 60-amp fuse.

Right Side of Amplifier:

  • RCA Inputs: two pair of stereo RCA inputs (Amp1 and Amp2); also used for speaker level input (up to two of item number 206KiSL needed, sold separately)

Amp Wiring Kit: Kicker recommends using an 8-gauge wiring kit with this 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

8 questions already asked

I have one of these driving just the component speakers in my rig. I don't know if it would make you super happy to run a 12 off of half of this amp; I mean it would definitely produce something, but wouldn't rattle license plates or anything. If you have a very small space to fill with sound (i.e. a standard cab truck) it would probably work, but I would be a bit reticent to use it alone for everything. I drive my subs off of a separate amp. Just my opinion though. [ Brian  Nov 10, 2015 ]
For details on fit or installation please contact an Advisor by phone (1-800-324-9695) or online chat. They will be able to pull up your vehicle and give you the details on if this will fit and what you will need for an installation in your vehicle. [ Krissy  Aug 10, 2015 ]  Staff
You will want to contact an Advisor by phone (1-800-324-9695) or online chat to discuss compatibility with your factory system. They will be able to pull up your vehicle and see if this will integrate. If it does not, then they will also be able to discuss other options with you. [ Krissy  Jun 09, 2015 ]  Staff
For details on fit or installation please contact an Advisor by phone (1-800-324-9695) or online chat. They will be able to pull up your vehicle and give you the details on if this will fit and what you will need for an installation in your vehicle. [ Krissy  Jun 08, 2015 ]  Staff
First of all, nice set up. That is exactly the set up that I have right now, except I am running of the stock HU. You should set the amp to the Hi I believe. That is what mine are at. The cross over you will need to play with a little bit. A good starting point would be to start in the middle and then adjust up and or down to get the sound that you want. For the x-over on each speaker, again you will prob have to try it and see what sounds best for you. I would imagine on this you would want it on Hi as well. [ Bryan  May 12, 2015 ]
Low on input and Off on Crossover Don [ Donald  May 11, 2015 ]
You will want to use the LO input on the amp and set the x-over on each channel to lpf at around 50 to 60hz. The speakers might be able to play lower but that doesn't mean they will sound good doing it. Why amplify weak sounding frequencies, good luck [ THOMAS W  May 11, 2015 ]
There is a switch on the amp that says something like input-hi-lo on it And there is one for each channel, amp 1 and 2. That functions as the crossover. I've set mine two different ways worth similar speakers. Setup 1: amp 1 low pass with the band set to approx 1/3 up from low going to the rear. Amp 2 hi pass set at the midpoint going to the front. This pushes all you bass to the rear and treble to the front. Setup 2: both amps on hi pass with the same points for band. This takes the low bass freq out of your front and rear, with lower mid in the rear. I am using setup 2 now that I got a bigger amp on my sub. [ Erik  May 11, 2015 ]
Thanks for your question. For information on selecting the best amp 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  Jun 05, 2014 ]  Staff
Thanks for your question. For information on selecting the best amp 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  Jun 05, 2014 ]  Staff