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Kicker KEY180.4

Compact 4-channel car amplifier with automatic tuning DSP — 45 watts RMS x 4

Item # 206KEY1804

Now you can get fantastic, high-quality sound without breaking the bank.

Read more from Crutchfield writer, Buck P.

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About the Kicker KEY180.4

Musical boost and tune-up

Now you can get fantastic, high-quality sound without breaking the bank. Kicker's KEY180.4 compact car amplifier features automatic signal processing that tailors the audio for your specific vehicle. This 4-channel little power pack will send 45 watts RMS to each of your front and rear speakers — more than twice the power of a typical aftermarket receiver, three or four times the power of a factory radio.

Musical boost and tune-up

Now you can get fantastic, high-quality sound without breaking the bank. Kicker's KEY180.4 compact car amplifier features automatic signal processing that tailors the audio for your specific vehicle. This 4-channel little power pack will send 45 watts RMS to each of your front and rear speakers — more than twice the power of a typical aftermarket receiver, three or four times the power of a factory radio.

KEY Auto Setup tunes in minutes, not hours

After installation, you set up the included calibration mic, start the test noise (downloaded from Kicker), hit the activation button, and the KEY Auto Setup software automatically sets the crossovers, 40-band EQ, and time-aligns the sound for the front seat driver. Then later, with the button, you can A/B the before- and after-processing sound, to amaze your friends and family.

Advanced features

You can manually enable Auto Compression, for a more consistent and safer power output. A limiter kicks in and lights up when it detects clipping, letting you know that something's too loud. A Bi-Amp mode lets you actively run tweeters and woofers without a passive crossover, by applying customized active crossover settings during the KEY Auto Setup process.

Start-Stop problem solved

Some eco-friendly cars actually turn off their engines when stopped, and then start up again when the brakes are released. The voltage dip during starting could shut down an amplifier or allow it to pass a dangerous clipped signal to the speakers. The KEY180.4 prevents these issues by automatically engaging its limiter in these circumstances.

Integrates well

This amp's so tiny, it'll fit almost anywhere in almost any vehicle. Kicker's FIT2™ technology, using speaker-level inputs with DC offset sensing turn-on, ensures this amp will work in almost any system, even one with a factory radio. The Radio-Detect switch makes sure you never get a "No Speakers Detected" message on your receiver's display when you install this amp.

Kicker KEY180.4

KEY180.4 with activation button and calibration mic


Product highlights:

  • 4-channel car amplifier/sound processor
  • 45 watts RMS x 4 at 4 ohms
  • CTA-2006 compliant
  • non-bridgeable — minimum impedance of 4 ohms per channel
  • Class D amp technology
  • KEY Auto Setup customizes the signal for your vehicle
    • calibration mic and activation button included
    • pink noise test tones available from
    • automatic adjustments include 40-band EQ, 24 dB/octave crossover filters, time alignment
  • Bi-Amp mode applies tweeter/woofer crossover settings during KEY Auto Setup
  • switchable auto compression
  • selectable high-pass filters (off, 60, 80, 120 Hz; 24 dB/octave)
Other Features:
  • automatic limiter with clip lights
  • preamp and speaker-level inputs
    • DC offset sensing turn-on with speaker-level inputs
  • Radio-Detect circuit supplies speaker load for receiver to sense
  • wiring and hardware not included with amplifier
    • 14- or 12-gauge power and ground leads recommended
  • fuse rating: 20A x 1
  • dimensions: 7-3/8"W x 1-3/4"H x 2-13/16"D
  • warranty: 1 year
  • Our 60-day money-back guarantee
  • MFR # Kicker KEY180.4

What's in the box:

  • 4-Channel amplifier
  • 12" Harness (power / ground / turn-on / speaker output)
  • 12" Input harness (4-channel RCAs)
  • 16" Loop of 14-gauge red power wire with in-line fuse holder
  • 20A ATO fuse (installed in holder)
  • Microphone with attached 11.5' cable (3.5mm plug)
  • Rubber microphone holder
  • 4 Self-tapping screws (length 1")
  • Two 12" wire ties
  • Owner's Manual
  • Quick Start Guide

Featured video:

Customer reviews

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Kicker KEY180.4 Reviews

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Overview: The Kicker KEY smart amplifier is designed to dramatically improve the sound quality of your vehicle's sound system automatically. The KEY 180.4 delivers clarity and solid power to your speakers. With the included microphone, you can run the Auto Setup process to optimize the audio for your particular vehicle. The amplifier can run four full-range speakers, or you can bi-amp a pair of component speakers. The amplifier is less than 8" long and 1-3/4" high, allowing you to mount is nearly anywhere.

Power Output: The KEY180.4 is a 4-channel amplifier designed to power up to two pairs of speakers, or one pair of component speakers. The amplifier is essentially divided into two 2-channel amplifier sections: Amp 1 and Amp 2. The amplifier provides the following power output: 45 watts x 4 RMS at 4Ω stereo (≤1% THD+N, 14.4V). The KEY180.4 must be run at 4-ohms minimum impedance per channel. The amplifier is not bridgable.

KEY Auto Setup: The KEY Auto Setup procedure helps the amplifier set individual speaker equalization, Kicker EQ, time delay, and speaker sensitivity matching. The included microphone should be placed on top of the driver's seat headrest to optimize the settings for that seating position. The Auto Setup begins when you press the activation button on the microphone cable. During the test, you will need to play uncompressed pink noise from the head unit through the speakers connected to the amplifier. Any speakers or subwoofers in the vehicle that are not connected to the amp should be turned off. Once the procedure is complete, the amplifier will play "happy" music to indicate successful completion, or "sad" music and beeps to indicate an error code. 

Gain Matching: The Kicker KEY180.4 makes it easy to set the input gain through a procedure called Gain Matching. The goal is to match the output of the source unit to the input level of the amplifier. The amp features a Limiter LED that lights up when the amplifier is clipping, allowing you to properly set the gain. Kicker recommends setting the gain using test tones for best results.

Limiter: The amp features a built-in limiter to protect your speakers and to assure continuous playback. The limiter is designed to engage in the following situations:

  • Engine Start: The amplifier is compatible with Start-Stop vehicles, and will not turn off during engine start. The limiter engages during engine start to prevent a clipped output signal from reaching your speakers.
  • Low Voltage: If the voltage on the power wire goes below +10.8V, the limiter will engage during moderate or high music volume levels.
  • Input Signal Overdrive: When the input signal causes the output to exceed the maximum rated power, the limiter will engage to prevent clipping. This is typically caused by the gain setting and/or the input signal being set too high. If this occurs, you should lower the input signal or the gain setting.

Controls: The controls are located on one end of the amplifier. A set of 8 DIP switches lets you configure the amplifier to your desired settings. There are two rotary gain controls for setting the input gain for Amp 1 and Amp 2. The DIP switches control the following settings:

  • Time Delay: Set to enable (EN) for all speakers' output to reach the driver (or the microphone location) at the same time. Set to defeat (DF) to turn off time delay.
  • Kicker EQ: The Kicker EQ is a 40-band equalizer that is automatically set during Auto Setup. You can set to enable (EN) to turn it on, or to defeat (DF) to turn it off. When off, the frequency response curve will be flat.
  • Bi-Amp Mode: You can bi-amplify component speakers, or door woofer/dash speakers. When the Bi-Amp switch is on, the amplifier will automatically detect and apply bi-amplification settings:
    • Woofers/Tweeters: 3.2kHz high pass for the tweeters (24dB/oct); 3.2kHz low pass for the woofers
    • Door Woofer/Dash Speakers: 320Hz high pass for the dash speakers (24dB/oct); 640Hz low pass for the door woofers
  • Compression: Auto Compression reduces high amplitude signals above a certain threshold to protect your audio system and provide more consistent sound. Set to enable (EN) to turn on compression, or set to defeat (DF) to turn Auto Compression off.
  • Fader: The fader switch lets you indicate the number of inputs you are running to the amplifier. Set to On if you are running two sets (front and rear, for example), or set to Off if you are driving all four channels with a single stereo input.
  • Auto Turn-on: You can use two different methods of automatic turn-on: run a dedicated +12V remote turn on lead (set DIP switch to 12V), or 3V DC offset on the speaker input wires (set to DC). Using DC offset puts +12V on the Remote Turn on wire for turning on additional amplifiers, if desired.
  • Hi-Pass Filter Options: The last two DIP switches can be configured to set the crossover frequency for the high-pass filter on the speaker outputs. The frequency can be set to 120Hz, 80Hz, or 60Hz. This Linkwitz-Riley High Pass filter has a 24dB per octave slope. The Hi-Pass filter can also be turned off, if desired.

Radio Detect: If you are using Hi-Level inputs, but the source unit cannot detect the presence of an audio system, or refuses to play audio from one or more speakers, you should set the Radio Detect switch to On. This activates a load resistor at the amp's input to indicate to the source unit that speakers are connected. Radio Detect should be set to Off if using Low-Level input signals. The amplifier's input sensitivity is 250mV to 10V.

Connections: The KEY180.4 has harnesses for the input signal, as well as for the power and output signals. The 4-channel Input Harness has two pairs of female RCA jacks for connecting a line-level signal from an aftermarket source unit. If you are using a factory head unit, or an aftermarket one without preamp outputs, you can cut off the RCA connections and splice the unit's speaker wires to the harness. The other harness has connections for +12V power, ground, and Remote turn-on, plus four speaker outputs. A short length of 14-gauge power wire with a 20A ATO fuse is provided for placement at the battery. Kicker recommends using 14-gauge wire (minimum) for the power wire from the battery to the amplifier. If you're bi-amping front component speakers or door woofer/dash speaker combinations, you should connect the tweeters to Amp 1 (front) and the woofers to Amp 2 (rear), and turn the Bi-Amp DIP switch to the On position. The passive crossover that typically comes with component speakers is not used when bi-amping.

Protection Circuitry: The KEY180.4 is equipped with a 3-way protection circuit that turns off the amplifier in the following situations:

  • Thermal: If the amplifier becomes very hot, its thermal protection is engaged. Overheating can be a sign of improper impedance on the speaker terminals or insufficient airflow around the amp.
  • Short Circuit: If the amplifier only plays at low volume levels, the short circuit protection is engaged. You should check for speaker wires that are shorted to each other or to the vehicle chassis.
  • Over/Under Voltage: If the amp shuts down only while the vehicle is running, the voltage protection circuitry is engaged. The amplifier is designed to operate at an input voltage between 6 and 16 volts. If voltage to the amplifier is not within this range, you should have the vehicle's  charging and electrical system inspected.

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Customer Q&A

Crutchfield asked: Why did you buy this?
I choose this to amplify the sound from my factory head unit so the new Kicker speakers I purchased will rock my truck. Jill was a big help with amp selection. Thanks Jill. [ John  Feb 07, 2019 ]
Couldn't get it locally and you have good warranty. [ Randy  Feb 03, 2019 ]
Sold on the Auto EQ feature. [ Anthony  Dec 31, 2018 ]
This is the second one I've purchased. I had such a great result with the first one, this is going in the other car. [ Jeffrey  Dec 12, 2018 ]
experimental I can't decide on an amp for my 2018 Mustang GT. I want a power amp and subwoofer for the trunk. [ Kevin  Dec 11, 2018 ]
Looks easy to install. Built in clipping indicator for clean sound. Should be much better than Pioneer deck power. Built in dsp with auto install has good reviews. [ Matt  Nov 24, 2018 ]
Love this amp with the DSP. [ Gregory  Nov 14, 2018 ]
like that it will tune for me. [ Nathan  Oct 04, 2018 ]
Seeing a review online made me curious [ JOSH  Oct 04, 2018 ]
Dsp auto programming [ michael  Oct 01, 2018 ]
Add power to new speakers since stock head unit cancels out bass at certain levels [ Karen  Sep 28, 2018 ]
I like the size of it so I can mount it under my front seat and not have to wire all the way to the trunk and just want a little more punch from my factory head unit [ Bogey  Sep 22, 2018 ]
Auto EQ [ Deborah  Jun 28, 2018 ]
Great way to get an amp with DSP for a factory head unit [ J  Jun 27, 2018 ]
I ordered this fix the crappy sound coming from the factory head unit. [ Jeffrey  May 29, 2018 ]
I like Kicker products and this new design will fit seamlessly with my particular vehicle. [ Rhett  Apr 11, 2018 ]

14 questions already asked

what if a car has noise cancelling? will this work?
[ Esteban  Mar 08, 2019 ]
1 answer
That's a great question! I feel that it would but I'm sure the Crutchfield team would have the answer to that.
[ Scott  Mar 09, 2019 ]
how does the auto tune work if I have a powered sub driven off of the aftermarket head unit with rca connectors?
[ Tommy  Feb 20, 2019 ]
5 answers
Auto tune just does dash and door speakers or whatever speakers you've connected to the key. The INSTRUCTIONS clearly state to turn off or disconnect the sub. So, disconnect the rcas from your sub or keep it off during auto tune.
[ Mark  Feb 21, 2019 ]
The auto calibration doesn't factor into the sub settings as Kicker states that the sub must be disconnected during the auto calibration process.
[ Miguel  Feb 20, 2019 ]
you turn off the sub when your tuning it
[ Dennis  Feb 20, 2019 ]
Kicker tells you to turn off or unplug the Sub when running the auto EQ. Then adjust your sub to your liking once your full range is setup.
[ Ryan  Feb 20, 2019 ]
Turn the sub off. I pulled the fuse and wince it auto tuned replaced. The auto tune is great.
[ michael  Feb 20, 2019 ]
I would like to run the amps 4 channels to a set of separates in the front (2 channels for the tweeters and 2 channels for the mids), then the Kicker powered sub under one of the front seats. Would this be a good use for this amp or is it better suited to full range speakers? thanks!!! Jim
[ Jim  Jan 29, 2019 ]
4 answers
Jim, I believe you can do that. I set mine up to run the tweeters and front mids together and the other 2 channels for the coaxials in the rear of my Jeep. It worked great except the auto tuning portion of the amp. Unfortunately that part doesn't work great for an open air vehicle but overall worth it for me. I hope this helps but if not, don't worry because Crutchfield techs are very helpful.
[ Scott  Jan 31, 2019 ]
Sorry, I returned it because I only needed a 2 ch amp with sub out, but that is exactly the way I was going to use it. You car should sound great. Jason
[ Jason  Jan 30, 2019 ]
Jim, I am currently running my amp in a 4 channel mode using 2 sets of component speakers. I really like this little amp. One of the best purchases I have made in a long time. If I had 2 of these amps I would utilize the bi-amp operation feature and run the separate tweeters and mids. I have all the confidence in this amp that using this mode would sound amazing. I have a Cerwin Vega powered sub in my trunk which is the slim sized one for under a seat. I just do not have enough room under my seat. I am very satisfied with the sound and range of the kicker amp for my fronts and rears, but when I get some more money, I want to invest in a more traditional sized powered sub. Those small compact sub's just do not go low enough. They seem to miss low end frequencies and even bottom out. My advice would be to run your Kicker Key in bi-amp mode and if your space allows, consider a more traditional sub.
[ SCOTT  Jan 30, 2019 ]
I wouldn't. The tweeters would be so loud you couldn't srand in. In that case you only need a 2 channel amp and run power to the mids.
[ LONNIE W  Jan 30, 2019 ]
will this fix eq on different sources? my factory radio should ok with cd, usb, and aux. but sounds horrible with radio and satellite radio.i have almost no bass with radio and satellite.
[ sam86  Sep 25, 2018 ]
3 answers
I installed mine on a kenwood head unit , it cleaned up the sound . I don't think it will help you with your issues. It must be something with your tuner on the radio . If you are having station and satellite issues . Because they both use a station signal . Hope this helps
[ Bruce  Nov 22, 2018 ]
I don't believe it's able to differentiate between sources. It has basic RCA/high level input and will process the signal with the same EQ adjustment across all inputs on the factory radio.
[ Ryan  Oct 04, 2018 ]
This did add a lot of low end in my 2016 Ram 1500. I have the 8.4 Nav radio with aftermarket speakers non alpine system. Had mid and highs all day long, but no bass. Huge difference with this amp. Still playing with adjustments, but very happy with sound. Satellite radio is hit and miss depending on radio. But should help the sound....
[ Steve  Oct 04, 2018 ]
Can you recommend a line out converter so that I can use to the DSP with higher output amplifiers, or is there a line of amplifiers that will accept the 45 watt RMS output of the Key?
[ caraudionewb  Sep 06, 2018 ]
2 answers
Any amplifier that can accept speaker level inputs will be able to handle the output of the KEY amplifier. Kicker amplifiers can accept speaker level inputs directly into the RCA inputs of their amps. That's what F.I.T. inputs are all about.
[ Bill  Sep 26, 2018 ]
Yes there is amplfires that will work
[ RICKY  Sep 07, 2018 ]
Can I use this app on my motorcycle and set it up using a microphone and everything to make my system sound better or I can only be use on a car?
[ Charles  Jun 04, 2018 ]
1 answer
The KEY Auto Setup feature is made for use in a vehicle. It is not currently recommended for use on a motorcycle.
[ Ryan  Jun 13, 2018 ]  Staff
What is the best way to connect a powered sub to this system?
[ Roberto  May 20, 2018 ]
2 answers
A powered subwoofer system would work completely independent of the KEY amplifier. If you're going to tap into the wires for signal, tap in BEFORE the Key amplifier, as the outputs will have EQ and time delay added.
[ Bill  Sep 26, 2018 ]
Powered subs don't use external amps. They have their own in the enclosure.
[ John  May 28, 2018 ]
Already have a sub install want to add this to my factory headunit how would you and the RCA for the sub with this unit by also using all the channels to run all four speakers ?
[ James  May 20, 2018 ]
2 answers
This can absolutely be done. The KEY amplifier will simply go in-line your factory speaker wires behind the factory head unit. And then you'll simply grab the signal for the subwoofer BEFORE the Kicker KEY amplifier.
[ Bill  Sep 26, 2018 ]
It has a configuration available to use 2 channels for the 4 door speakers and 2 for the sub.
[ Matthew  May 20, 2018 ]
How does the signal processing in this unit compare to the Kicker Front Row processor? Which delivers a better sound stage?
[ Matt  May 17, 2018 ]
2 answers
Both pieces feature EQ and time delay adjustments. The KEY amplifier does this via a microphone and Auto-Setup process. The results it calculates cannot be adjusted by you. The Front Row does nothing automatically, but allows you to change and fine-tune any and everything. Two different pieces for two different types of customers. :-)
[ Bill  Sep 26, 2018 ]
Thanks for your question. For information on comparing two or more models 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 and help you make the best choice for your system and your budget.
[ Krissy  May 25, 2018 ]  Staff
How will this interface with a factory Ram 2500 Uconnect head unit? Is there a adapter or harness?
[ david  Apr 26, 2018 ]
1 answer
For more details on vehicle-specific fitment or installation please contact an Advisor by phone (1-800-324-9695) or online chat. They will be able to pull up the research for your Ram 2500 model to help determine the best option for installing the Kicker KEY180.4 amplifier. Thanks! :)
[ Larry  May 05, 2018 ]  Staff
Does this have speaker level inputs and outputs? There seems to be conflicting information in the item description.
[ PaulS  Apr 18, 2018 ]
1 answer
This amp has both speaker level inputs and outputs. The inputs are done a bit differently and most amps. This amp has RCA inputs that you cut off to get back to bare wire so you can use those inputs with speaker level signals. HTH! My Bio:
[ Paul  Apr 30, 2018 ]  Staff
I see it requires a 4 ohm load. My alpines are 3 ohm. Is it a bad idea to use this to push them? Will it even work?
[ Danan  Apr 09, 2018 ]
2 answers
You can call Kicker tech support to verify if you'd like, but I've run the Kicker KEY with 3 ohm JBL speakers and even 2 ohm Infinity speakers no less than 10 times without one single hiccup after months of use. Kicker tech told me it was fine, but the amp will not output any more power.
[ Bill  Sep 26, 2018 ]
The Kicker KEY180.4 amplifier must be run at 4-ohm (minimum impedance) per channel. For more details or to discuss further, please contact an Advisor directly by phone (888.955.6000) or online chat. Thanks!
[ Larry  Apr 24, 2018 ]  Staff
Does anyone know if 2 of these can be used together? I want to run my front speakers active, and then run my rears off of another. If I do that can I use the auto EQ and TA on the rears?
[ Anthony  Apr 05, 2018 ]
2 answers
Only one of the amplifiers can use the auto-setup process. The second amp would have to be used as a "dumb amp". Just a regular 45Wx4 amp. So use the smart amp on the fronts, and dumb amp (or just head unit) on the rears.
[ Bill  Sep 26, 2018 ]
For more specific questions related to your system, you'll be better off contacting an Advisor directly by phone (888.955.6000) or online chat. They'll be able to offer a more detailed explanation to make sure the Kicker KEY180.4 is the right fit; and if not, they can suggest a suitable alternative. Thanks!
[ Larry  Apr 16, 2018 ]  Staff

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