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Raxiom by JL Audio Base Stereo Subwoofer Upgrade Kit (15-20 Fastback)

Item 393866
Market Price $1,342.99 You Save 11% ($143.00)
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    Features, Video & Details

    • Raxiom Subwoofer Upgrade Kit by JL Audio
    • Delivers Deep, Powerful Bass
    • 12TW3-D4 Stealthbox Subwoofer
    • JL Audio JX500/1D Class D Amplifier
    • All Cables and Connectors are Included for a Hassle Free Install
    • For use with the Raxiom by JL Audio Base Stereo Upgrade Kit - 393865
    • Fits 2015-2020 Fastback Mustangs Equipped with Base Stereo Upgrade Kit

    Review & Installation Video

    Review & Install Video

    Hey, everybody, I'm Justin with, and in this video, I'm gonna be taking a closer look at the Raxiom by JL Subwoofer Upgrade Kit for all 2015 and newer Fastback Mustangs, equipped with a factory subwoofer. Now, in my detailed breakdown, I plan on talking about why prospective buyers might wanna upgrade their factory sub in their Mustang with a 12-inch option here from JL. We'll talk about what's included with the kit along with some of the specs, and then finally, we'll cover a brief, little overview of the installation process. I'm gonna go solid two out of three wrenches here on the difficulty meter due to the light wiring of course, but we will have some more detail on that later on.Now, the JL kit that we have in this video, again, will appeal to those 2015 and newer Fastback owners who have the Shaker Pro Audio System with the 12 speakers in the factory subwoofer, but feel like the factory sub just tends to fall a little short in regards to overall output or quality. Now, by going with this turnkey system here from JL, you're gonna be replacing that 8-inch factory subwoofer and the 100 watt factory amplifier with one of JL's 12-inch subwoofers and corresponding 500 watt amps. So, in turn, you're gonna be getting a much bigger bass response overall, a lower frequency range, and just a lot more thump, while still essentially maintaining the same amount of usable space in the trunk. And with all that said, I do feel like the biggest appeal with this kit here from Raxiom and JL is the fact that it is a turnkey system, essentially ready to rock and roll right out of the box.Now, could you piece together a different system using different components maybe save a couple of bucks? Sure, but this is a convenience factor, guys, you're getting everything you need from soup to nuts right out of the package. Yes, you gonna be spending a little bit more money for that, but you are getting quality components in return, and again, this thing is ready to install the moment you unbox it. So, Ford has been using their patented Shaker system for pretty much as long as I can remember, and for the most part those higher end Shaker offerings do produce enough sound and enough bass response to satisfy most owners. However, like anything in the aftermarket, some people just aren't satisfied with that and are looking for ways to improve with what the factory gave them. And that's pretty much what this kit will appeal to.Now, I can personally attest those factory Ford subwoofers do leave a lot to be desired, especially if you like a more bass heavy listening style. Now, the problem is outfitting or upgrading the subwoofers without totally dominating the trunk space like those old bandpass boxes back in the day, but still at the same time providing you with enough low end response or bass to round out the other 11 speakers in the 401A Shaker Pro package. So, Raxiom JL, they put their heads together, came up with a solution for that problem and that's what we're looking at here today. But, let's break down the individual components here of the upgrade kit from JL and Raxiom, and the star of this kit, at least in my opinion, is no doubt gonna be the JL 12 TW3 subwoofer, which is just a massive upgrade over that 8-inch factory paper cone woofer in every single way.Now, what makes the TW3 really special is that it produces a fantastic bass response, but it's still very shallow or very thin. In fact, this speaker itself is only 3.5 inches deep. So, that makes it very appealing to throw in tight spot like this because, as you can see, it really doesn't need a massive enclosure to sound really good. So, how did JL accomplish this with their TW3 line up? Well, they basically took a traditional woofer and just turned it inside out. And what I mean by that is, if you can envision a speaker, if you ever seen one outside of an enclosure, you know you have the cone and then the skeleton or frame, then hanging off the back of the speaker itself you have what is called the motor structure basically containing your magnet and all that other good stuff, looks like a big hockey puck basically hanging off the back of the speaker, and that's typically what is gonna add the most depth. Now, JL with a TW3 basically took that and put it inside the skeleton or frame of the speaker, thus cutting the depth of the speaker in half. Also loaded in the TW3 have some of JL's patented tech first of up, you have this concentric tube design and there's a lot of techie stuff at play here, but basically, this means the speaker itself will be more linear and essentially just sound better at any volume, especially when it's really cranked up.But let's break down the construction of the speaker and talk about why it is such a massive upgrade over that factory woofer. Now, on the surface, you're looking at an injection-molded mica-filled polypropylene cone -- yes, that's a mouthful -- a rubber surround, alloy frame, and the aluminum dust cap that does cover up that concentric tube design we just talked about. Compare that to the paper element factory cone, the foam surround, again, just not a very nice construction with the factory piece, and as such, this bad boy is gonna be a huge upgrade. On top of that, everything is assembled in built right here in the USA.The 12-inch sub from JL does feature a dual voice coil design, operating at 4 ohms, but can be wired to a 2-ohm impedance if you like. And on top of that, will handle 400 watts of continuous power. Now, that leads me to the next part of our upgrade kit here, the JL JX500/1D Monoblock Amplifier. The JL amp is a Class D single channel amp that is designed to push a subwoofer, can handle 300 watts RMS at 4 ohm, 500 watts RMS at 2 ohm at 14 volts. Expect those numbers to drop a little bit more at 12.5 volts. The JX500 does feature an operating range from 50 to 200 hertz along with a 12 decimal boost level if needed. Just an FYI here, guys, JL recommend starting at around 80 hertz for your sub tuning pleasure, and just kind of working off of that. You're also looking at both high and low level inputs along with a low pass filter which is kind of par for the course when you're talking about a dedicated sub amp like the JX500.Now, one thing that JL tosses in with this amp and something that I'm a huge fan of is this RBC dash one knob here that plugs into the amp and essentially gives you, the driver, the ability to control the volume of the subwoofer itself or muted completely depending on what you're after. Now, that's something that's not always easy to do with a factory integrated system like this, but the fact that they throw that in is a small but very worthy upgrade to the system.All right, so we've talked about the sub, we've talked about the amp, let's break down what else you are getting here from JL with their kit. Now, we talked about the TW3's ability to boom in small places, and of course, that is the case here as you are also receiving one of JL's patented stealth box enclosures. Now, this enclosure will be replacing your factory sub and enclosure as well, and one of the big draws with the Stealth Fox technology from JL is that you're really not giving up any extra trunk real estate and that certainly is the case here again with this particular kit.The box itself is made from fiberglass, it is a sealed enclosure and it has been finished off in this charcoal carpet which does match nicely with your other trunk material. In addition to the sub box, amp, all that good stuff, JL does throw in everything and I mean everything you need to get this thing up and running including your power wire here, 3 feet of ground wire, a remote cord or cable, speaker wire, RCA cables, and also a fuse block as well. They even go as far as throwing in some zip ties and a little rubber grommet to be used whenever you drill your firewall to run that power wire into the engine bay and back to the trunk. So again, very, very complete and definitely takes all of the guesswork out of this kit for you.And this seems like a great time to transition into the installation here, guys. Really not all that bad, again, especially if you tinkered around with car audio stuff in the past. I'm sticking with two out of three wrenches on the difficulty meter. Maybe a few hours to a half a day in the shop or garage to get it knocked out. Yes, there is some light wiring involved, but JL makes it very, very easy thanks to everything that is included with the kit. Again, very complete is a great word for it. Yes, you will need to run that power wire into your engine bay, wire it up to your battery, simple stuff there.You're also gonna need to find a place for the JL amp to live, some guys might wanna go in the trunk, others might wanna go underneath the seat to spring more stealthy install. Whatever the case, you have to run the wire to that as well. So, really not that bad, but overall, I am sticking with two out of three wrenches on the difficulty meter. If you're not terribly confident in car stereo stuff or wiring in general, you might wanna have a local audio shop or even a buddy help you out with this install. Either way, it should be very straightforward.Wrapping things up here with the JL kit, guys, if you're a big fan of music and you love that low end response from a subwoofer and been pretty disappointed with the factory 8-inch woofer, you're gonna love this kit. It does include everything you need to get it up and running right out of the box. Sure, you're paying a little bit extra for it, but folks who know JL are gonna appreciate the quality of the components. Listen, you're getting a huge upgrade in bass response from the 12-inch woofer to the 500 watt amp, you're really not gonna be disappointed here.So guys, that is my review of the Raxiom by JL Subwoofer Upgrade Kit, which you can grab right here at

    Raxiom by JL Audio Optional Subwoofer. If you have upgraded your S550 Mustangs base stereo sound system with the Raxiom by JL Audio Base Stereo Upgrade Kit we bet your pretty happy with the results. However, if you love the sound of a deep, powerful bass you my feel that something is missing. That is why Raxiom turned to JL Audio yet again to help them find the perfect Subwoofer set up for their Base Stereo Upgrade Kit. By utilizing JL Audio's Stealthbox Subwoofer and Class D Subwoofer Amplifier this optional Upgrade Kit will deliver the deep, powerful bass you love.

    Stealthbox Subwoofer. This Raxiom Subwoofer Upgrade Kit includes JL Audio's 12TW3-D4 Stealthbox Subwoofer. The Stealthbox Subwoofer is a direct fit upgrade for your factory installed base stereo that has been upgraded to a Raxiom Base Stereo Kit part# 393865. The Stealthbox features an all-fiberglass, sealed enclosure design that is equipped with JL Audio's revolutionary 12TW3 thin-line subwoofer.

    JX500/1D Amplifier. To boost the power of the Stealthbox Subwoofer Raxiom chose JL Audio's JX500/1D Amplifier. This Amplifier employs a highly-efficient Class D design with a MOSFET power supply to deliver a strong 500 watts. Featuring a variable bass boost at 45 Hz with up to 12 dB of boost, this JL Audio Amplifier is configured as a low-pass filter with continuously variable cutoff frequency selection from 50-200 Hz. Dedicated hi-level inputs are included, in addition to conventional low-level RCA inputs. These inputs make it super easy to install the JX500/1D Amplifier to your original factory head unit.

    Application. This Subwoofer Kit was specifically designed to fit 2015 to 2020 Fastback Mustangs that are equipped with the standard OE base stereo system and have installed the Raxiom by JL Audio Base Stereo Upgrade Kit part# 393865.


    Fitment: 2015 2016 2017 2018 2019 2020 Details

    MPN# 393866

    CA Residents: WARNING: Cancer and Reproductive Harm -

    What's in the Box
    • (1) Class D Subwoofer Amplifier
    • (1) Stealthbox Subwoofer
    • (1) Remote Bass Control
    • (1) 2-Way Fused Power Distribution Block
    • (1) 2-channel Core Audio Interconnect Cable
    Installation Info
    Will it fit my Mustang?
    • Bullitt - 19, 20
    • EcoBoost - 15, 16, 17, 18, 19, 20
    • GT - 15, 16, 17, 18, 19, 20
    • GT350 - 15, 16, 17, 18, 19, 20
    • GT350R - 15, 16, 17, 18, 19, 20
    • GT500 - 20
    • V6 - 15, 16, 17

    Fits Mustangs that have installed the Raxiom by JL Audio Base Stereo Upgrade Kit part# 393865.

      Customer Photos

        Questions & Answers (17)

        5 Top Rated Questions

        I have factory speakers in my car know and looking to upgrade the bass sound. Can I just buy this kit and it still work with my factory speaker or will I have to upgrade to the speaker kit. Just looking for a stealthy look without have to pay a lot of money by upgrading everything in my car

        • This was specifically designed to fit 2015 to 2019 Fastback Mustangs that are equipped with the standard OE base stereo system and have installed the Raxiom by JL Audio Base Stereo Upgrade Kit part# 393865found here:

        Helpful (1)

        Would all factory wiring work with the upgraded amp? The power wire?

        • It is not necessary to use the factory wiring. This kit will include all the wiring you need, including the power wire

        Helpful (1)

        Will this work for a stock audio system in a 2015 3.7 mustang?

        • This is only for use with the Raxiom by JL Audio Base Stereo Upgrade Kit, item 393865. lt is not compatible with the stock system.

        Helpful (0)

        Where do I need to run a remote on wire to? I've searched for diagrams on the factory wiring layout and havent found anything.

        • There will be instructions for wiring this included, and if you are not confident wiring this yourself, we suggest having a local audio shop take a look at this and get it installed for you!

        Helpful (0)

        The base stereo upgrade is not available. Will this subwoofer install work with the base stereo?

        • From my understanding, the subwoofer will require the base stereo upgrade which can be found here:

        Helpful (0)
        Post Your Question
        10 More Questions
        Does this kit work on 2018 Mustang non subwoofer base touch screen headunits? 1 answer
        I have a gt350 with the 9 speaker electronics package is this the correct package for my car? 1 answer
        I did not have the 401A package in my 2015GT. Will this package work since this an upgrade from the one in the package. If so, how easy it it to be installed. 1 answer
        Will this work even if your 2015 mustang didn’t come with stock speaker ? 1 answer
        Would this work on a upgraded sync “8 touch screen. 1 answer
        I've got a GT350 with the Tech package that has a "7 speaker" setup. I'm figuring that this is the stock 6 speaker center dash speaker. Has this kit as well as the Base Stereo Upgrade Kit part# 393865 been installed on a GT350? If so, does this require any additional wiring/config? 1 answer
        is it valid for Convertible Mustang 2018 too? Luis 1 answer
        about to get my 2018 mustang on the with the 9 speaker audio system (301A package) can i use this kit with a line out convertor that taps into the rear speakers for the audio signal? 1 answer
        Does this work with the 16' Ecoboost premium convertible with the Shaker System? 1 answer
        Will this kit work in a 2017 GT350? 1 answer

          Customer Reviews (1) Write a Review

          Overall Rating 5

          out of 5 stars

          • 5/5

            December 06, 2016

            Great quality

            Perfect fit. I love it! I love how the hardware is specifically customized for my car. Other than the outstanding amount of money it was, i have no problems.


            Year: 2015 Submodel: Ecoboost

            Helpful (17)