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Raxiom by JL Audio Base Stereo Subwoofer Upgrade Kit (15-18 Fastback)

Market Price $1,342.99 You Save 11% ($143.00)
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  • Item 393866
  • MPN# 393866

  • Add InstallerNet Stereo Installation Service

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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
  • 2 Year Full Warranty
  • For use with the Raxiom by JL Audio Base Stereo Upgrade Kit - 393865
  • Fits 2015-2018 Fastback Mustangs Equipped with Base Stereo Upgrade Kit

Review & Installation Video

Review & Install Video

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.

Full 2 Year Warranty. Raxiom is so confident in the quality and workmanship of their products that they are covered by an "Industry Leading 2 Year Full Warranty".

Application. This Subwoofer Kit was specifically designed to fit 2015 to 2018 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 Details

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?
  • EcoBoost - 15, 16, 17
  • GT - 15, 16, 17
  • V6 - 15, 16, 17

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

Customer Photos

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3 Questions / 2 Answers

Ask a Question

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 as well as the stereo upgrade kit fit with the mustangs that did NOT come with the factory sub in the trunk?


  • This stereo upgrade kit is only designed for the 15-17 mustangs with the OE style upgraded stereo or with the Raxiom upgrade kit. This can work with the mustangs without the factory sub with modification of the kit but it is not recommended.


Helpful (0)

Is the 'Audio Base Stereo Upgrade Kit (product #393865)' required for the install of this subwoofer? Also, will the sub be compatible with Australian import models of the GT? Cheers.


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Customer Reviews (1) Write a Review

Overall Rating 5.0

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 (1)