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JL Audio Stealthbox®

Custom-fit fiberglass enclosure with 8" W3v3-4 subwoofer — fits 2008-up Smart fortwo

3 Reviews

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Item # 13694448

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$599.99 or 3 payments of $200.00  Details

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Our take on the JL Audio Stealthbox®

The JL Audio Stealthbox® custom-fit subwoofer delivers incredible bass in a package that takes up minimal space and blends in with your vehicle's interior. JL Audio designs Stealthboxes to fit in specific vehicles, then loads them with appropriate subwoofers for optimal performance. Pair the system with an appropriate amp and wiring for stellar concealed bass.

JL Audio Built In USA The JL Audio Stealthbox® custom-fit subwoofer delivers incredible bass in a package that takes up minimal space and blends in with your vehicle's interior. JL Audio designs Stealthboxes to fit in specific vehicles, then loads them with appropriate subwoofers for optimal performance. Pair the system with an appropriate amp and wiring for stellar concealed bass.

Perfect sound to go with the perfect fit
JL Audio puts months of research and design into each Stealthbox® custom-fit subwoofer to ensure not only that it fits, but that it sounds better than any other custom enclosed system. First, JL Audio determines the ideal shape and mounting location for each enclosure, so that it looks like an original part of the vehicle it's designed for. Next, they mount each high-performance subwoofer so it delivers amazing firepower from within its unique enclosure, without sacrificing clarity or musical depth.

The fiberglass enclosure offers superior rigidity while allowing more interior volume, so the sub can turn out louder, deeper bass. JL Audio craftsmen then laminate, grind, join, and finish each Stealthbox® by hand. The end result: full-bodied, distortion-free bass from an impressively stealthy enclosure.

Enjoy enhanced, custom-fit sound
This Stealthbox® enclosure fits your 2008-up Smart fortwo. It installs under the dash on the passenger side. This Stealthbox® includes one 8", 4-ohm W3v3 subwoofer from JL Audio. The included steel-mesh grille protects the sub. Please check with us before purchasing by using the vehicle selector on our site, or calling an Advisor at 1-888-955-6000 to verify fit information.

JL Audio has rated the difficulty of this Stealthbox® installation as high. Crutchfield recommends using a car audio professional to install this enclosure, unless you have extensive experience installing car audio gear.

Product Highlights:

  • Stealthbox® custom-fit subwoofer
  • sealed fiberglass enclosure
  • 8" 4-ohm W3v3 subwoofer
  • steel-mesh grille included
  • fits under the dash on the passenger side
  • power handling: 50-250 watts RMS (500 watts peak power)
  • warranty: 2 years
  • Our 60-day money-back guarantee

What's in the Box:

  • Custom subwoofer box with loaded 8" woofer
  • 4 Custom brackets
  • 1/4-20 x 12" All-thread rod
  • Three 1/4-20 x 1" hex-head bolts
  • Two 3/8-16 x 1" hex-head bolts
  • 3/8-16 x 1-1/2" hex-head bolt
  • 1/4"-20mm Hex-nut
  • Two 3/8"-16mm hex-nuts
  • Six 1/4" Split-lock washers
  • Five 1/4" Flat washers
  • Three 3/8" Split-lock washers
  • Five 3/8" Flat washers
  • 1/4"-20mm Speed-clip
  • Installation Guide
  • Warranty sheet

JL Audio Stealthbox® Reviews

Average Customer Review(s):

(3 Reviews)

Great improvement for Smart car.

Scott from Madison, ME on 11/13/2016

2009 Smart fortwo
Crutchfield Customer Review (What's this?)

Very well constructed, sounds great! It takes some time to get it in, but I ended up modifying the heater duct and removing and reinstalling diverter motor for a much easier install. These two steps made it MUCh easier. Also dont take the sub out of the box, too hard to reinstall after the box is mounted. Thats the reason I cut the duct and fiddled with the motor. Only put 3 screws back on diverter motor but it does not create an issue.

Pros: Quality all the way, hidden, great improvement to sound.

Cons: Should have the simple mod of the duct cut and diverter motor removal instead of removing sub.


RMTZJR from Texas on 8/21/2015

2008 Smart fortwo
Crutchfield Customer Review (What's this?)

Incredible! The install is super easy up until actually fitting the sub in the space. My recommendation, take the speaker out of the box and reinstall the speaker after everything is mounted. Incredible sound, I had a 12" sub in the back of my Smart, and am now selling it, cause this 8" hits cleaner, more efficiently and I am in LOVE with it! You can hear it everywhere, top down or not. I have a 2008 Cabrio ForTwo

Pros: Incredible sound, invisible to the outside world.

Cons: Putting the sub in place is a little tough, but not impossible.

big bass in small car

G Michael from Alpharetta, GA on 6/14/2012

2008 Smart fortwo
Crutchfield Customer Review (What's this?)

There's a comparable underdash setup for The Smart's at half the price- with a 1/4 of the bass performance- still an improvement even over the Smart's that have the underseat sub (as mine did), but neither compares to this JL Smart car sub. I truly believe JL Audio did their homework to give you no holds barred clean and powerfull bass is a stealth setup. I've been a loyal fan of their subs for years, so I had high expectations of this setup- and it delivers. Nice punchy bass with well defined notes in a sealed enclosure- not the crappy bandpass peaky sound. Wanting to keep the whole thing stealth, I also purchased the XD400/4 channel JL Audio amp and bridged two of the channels to run the Stealthbox. Amp fits under the seat with room. It's insane! - For those that are looking for the ultimate setup for a Smart- this it it- and it's stealth to boot. For those that want it- the Smart Car becomes a giant boom box. My vehicle is the Smart Cabrio- a droptop is the worst car to get a stereo to work nice in, however this one has gorgeous clean sound in even with the top down (much in part to Smart's well thought out component speaker placement). I'm still using the Smart's OEM premium sound front stage speakers on the remaining two channels- when those go, I'll be looking at a JL component set.

Pros: For those who know JL Audio, it's everything you would expect from JL Audio. Stealth setup. Very high quality fit and finish, high quality components- lots of pride in manufacturing detail.

Cons: Cheaper stealth setups exist- and come with cheaper performance.


Hands-on research

Product Research


Overview: JL Audio's Stealthbox subwoofer systems are designed to hide away in a specific vehicle. Please consult "Outfit My Car" to confirm compatibility with your vehicle.

Construction: Stealthboxes are hand-crafted from fiberglass and/or Advanced Molded Composite (AMC) materials. Fiberglass delivers a level of enclosure rigidity and dimensional stability not possible with other enclosure materials, allowing wall thickness to be reduced compared to a typical wood enclosure. This gives you more interior box volume for a given external volume. Fiberglass and AMC materials are very strong and can be molded into very complex shapes; giving JL Audio the ability to design your Stealthbox to fit perfectly into tight spots and minimize intrusion into your vehicle's useful space. Each Stealthbox is laminated, ground, joined, and finished by hand in the USA. Proprietary techniques and materials developed by JL Audio through years of fiberglass manufacturing experience ensure consistent quality and performance.

Woofer: One 8" JL Audio W3v3-4 subwoofer is loaded in the sealed enclosure and wired as an 4Ω load the enclosure's 5-way post speaker terminal.

  • Dynamic Motor Analysis (DMA): DMA is JL Audio's proprietary method aimed at improving dynamic motor behavior. As a result of DMA optimization, W3v3 motors remain linear in motor force over a very long range of excursion, and also maintain a highly stable fixed magnetic field in the gap over a wide power range. The result is vastly reduced distortion, faithfully reproduced transients, and tight, clean, articulate bass.
  • Floating Cone Attachment Method (FCAM): JL Audio's patented FCAM technology is an innovative method of bonding the surround/cone assembly to the voice coil/spider assembly. This assembly technique ensures proper surround geometry in the assembled speaker for better excursion control and dynamic voice coil alignment.
  • Vented Reinforcement Collar (VRC): The Vented Reinforcement Collar is a composite structure that addresses two issues related to reliability. By reinforcing the critical junction between the cone, voice coil and spider, the VRC greatly reduces failures due to glue breakdown or material weaknesses. It does this by greatly increasing adhesive contact area and providing stress relief to the spider material at excursion extremes. the VRC also feature slots that facilitate air flow directly onto the voice coil windings to reduce thermal compression effects and enhances reliability.
  • Spider/Lead Wire Assembly: The W3v3 features a unique spider, coil and terminal subassembly which is assembled prior to installation in the speaker frame for optimum alignment and glue-joint integrity. The spider is insert-molded into a composite carrier tray which also incorporates the terminal assembly and lead wire strain relief features for enhanced reliability and optimal alignment of parts. The flying lead wires are carefully controlled and strain-relieved without resorting to woven-in lead wires, which can degrade spider performance.
  • Elevated Frame Cooling: The elevated frame design of the W3v3 delivers high-velocity air flow through slots directly above the top plate to the voice coil of the speaker. This not only enhances power handling, but also sound quality by minimizing dynamic parameter shifts and power compression.
  • Surround Stress Relief: By creating a radiused feature on the edge of the cone, stress is relieved from the surround material at maximum forward excursion, resulting in longer life and more consistent surround behavior.

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.

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