Kicker 47KEY2004 Key 4-Channel DSP Smart Amplifier, 4x50W

This DSP and amp is amazing! It gives a huge new dimension to your music. It's pretty small, and it's light, so it can fit in a lot of locations. It's very powerful. You won't need another more powerful amp on the side as well. I can only turn up my volume about 1/3 of the way before it gets unsafe (90dB) to listen to. The color coded wires are helpful and easy to follow.

What an exceptional little amp. The sound quality is phenomenal, the clarity is fantastic! I combined this with Kicker KS series 6x9 components up front and 6.5 coaxial speakers in the rear of my 2019 F150 XLT. I wish I had done this years ago. Only small crux is I ended up needing to run a remote turn on wire as the auto turn on wasn't functioning properly in my truck. One wire and a lot of rerunning wire and it started up with zero issues. I really hope that Kicker expands the Key technology further in the future. It's now a proven concept that can match the performance of most DSP setups but adds the value of being DIY friendly for those of us who prefer to install our own equipment or cannot afford a full DSP setup and the associated installation and tuning costs and or headaches. I'd love to see Kicker offer a higher watt version of this amp. If and when they do, I'll be seriously considering an upgrade. Not to say that this isn't powerful though, I honestly can't crank it all the way up because it's too loud. I love being able to say that! Also it makes all kinds of music better. It truly doesn't matter what you listen to, you will hear instrumentation and vocals that you have never noticed before while listening to your all time favorite songs.

Big improvement over stock in 2025 Ford F150. Very clear at higher volume. With upgraded speakers, the system has vastly improved over the factory non B&O system.

This is a compact amplifier with great sound stage. I installed this in a 2025 Kia K5 GT. The amp cleared up the sound in my door speakers so I can actually hear the words at a decent volume. I also replaced my stock door speakers with a set of Rockford Fosgate speakers. Great buy.

This little amp is it. It works, does the job for daily car, and I think its well for daily driver. The amp is small, very compact and it serves the purpose that it can hide almost anywhere. The auto tuning function is actually working and the good thing about it is that you only gotta do it once.

Awesome sound.. install in a 2023 Honda Ridgeline, that was the hard part...the Noise canceling device in the Honda was a pain in the butt to find and shut down. I would buy this amp and again.

Installed this on my car, sound quality has improved a ton, sound has more depth to it and it is way more clear now. This unit is compact and doesn’t require a ton of power, install and setup was pretty straightforward. Only downside is it does have a noise floor, since the amp is so small, internal components cause a little bit of noise, barely perceptible but if you have sensitive hearing it can be annoying until you play some music or sound. If your car is running you probably won’t notice it.

Used this in a 66 mustang complete build. Made custom pods for the kicks with tweets six inches above. I have a very nice set of 5.25" CT Sounds components that sounded like a dumpster fire smothered in hot fecal matter. I knew that they needed more power than they are getting from the deck so I went looking for a two channel amp to liven them up. Ended up buying this four channel Kicker after reading lots of reviews. I received the amp on time as expected. It was MUCH smaller than it seemed in pictures. Did the install fitting it all inside the glovebox of the mustang and guess what. Still sounded like garbage only louder. Next step was to hook up the microphone and set up the DSP equalizer, time delay and crossover network. I installed the mic on the headrest and ran the pink noise track. Five min later after some wizardry this thing sounds awesome. Flattened out the mids and tweets blending great with the sub after I plugged it back in after the calibration. I could not be happier with the install and the sound. If you make this purchase please take the time to use the DSP. It makes a world of difference.

I used this product to augment an old Mercedes’ 1970’s Becker stereo. I like my old stock head unit because it’s stylish, matches the old classic car and was quality back in its day. Today though… it’s poor sound quality. Ancient paper cone speakers, 4inch in front, 5inch in rear. I inserted the kicker key 200.4 into the system to work it’s electronic magic trickery. Once installed, I used the self-tuning system with the supplied microphone. The results are staggering. Somehow my ancient tiny speakers have acceptably good clarity and even acceptable levels of bass. They are all matched in volume, and the sound stage sounds like it’s right between my ears when sat in drivers seat. Superb product for lifting an worn out old stock system into the present day. Impressed with kicker yet again. Have ordered a set of their entry level speakers now as a follow up from these excellent results. Just a word of warning though… in old cars with earthed negative returns on the speakers, you will need to wire both negative and positive from/to the speakers and cannot earth the speaker inputs to ground. Because It’s a class D amp. (Same with any class D amps, not just kicker). Enjoy. There is also just a whisper of white noise from the amp when powered up, but no music playing. This needs to be improved for future models Kicker!

When it arrived it was smaller than I expected which made installing it behind the dash on the passenger side possible (2021 Corolla) I installed this after installing some Focal speakers and the improvement in the sound is great after the auto calibration!

Excellent ampli avec dps et 50watts x4 fonctionne très bien dans mon chevrolet bolt ev 2023.

Sí cambia bastante el sonido, un poco “alto” en los agudos para mi gusto, pero suena mucho mejor que el estéreo original sin él. Bajando los test tones es bien fácil de configurar

Installed this in my 1936 ford coupe. I had to do a little bit of wiring as I was replacing a different AMP. Works good and I have not done the auto configure yet waiting for warmer weather.