JL Audio "Stealthbox" Sub woofer

[8/19/2005] Reviewed by: Brendan - theronaldklene@yahoo.com

Applicable to: '90 - '97 '99 + 1.6 liter 1.8 liter

JL Audio Stealthbox... dual 8" subwoofer in fiberglass box right behind the hearrests.

Installation was short, I didn't find it neccesary to bolt it in, stays VERY secure with the cockpit brace bar I had to install(must be purchased seperately, oem is prefered). I bought this box off off ebay, already finished with black speaker cloth, so I'm not sure how matching the old carpet is that comes with it. When I bought it, it had no subs in it. (JL Audio 8w3v2's) I installed two Klipsch RW-8 subwoofer drivers I got off ebay in it and had to build an extender to raise the subs up(the magnet was touching fiberglass) Matched with a Kenwood 600 watt amp, this system is amazing. If you want to be the guy rolling down the street annoying the hell out of everything, DO NOT BUY THIS. If you want good, low, accurate bass in your fix, that can shake your heart inside the car, hit it up. Highly recommended, but the price is too high I think.

Overall... Pro's-nice sound quality, great decore, impossible to steal(if you install it all correctly, I didn't), great costumer service. Con's-over priced, other than that, none noted

Difficult to remove without leaving damage

[4/8/2001] Reviewed by: Kenneth and Kaylene Winters

I just installed the best subwoofer money can buy for the Miata. http://www.jlaudio.com/stealthboxes/miata.html  I got it at Innovative Audio in Bellevue WA. http://www.innovativeaudio.com from Brian Mills. Brian it was worth the wait. I had a bad experience with the Car Toys people. I see that JL Audio has updated the web page and Good Guys is a dealer as well. It was $650 a bit pricey in an economy that is talking of layoffs and cut backs, but after I got it I was glad I did. The product is well built with attention to the look as well as the function.

My wife and I have had our Miata for 11 years. We had the stock CD/Radio/Tape system with added headrest speakers (Kenwood 3 1/2"). Well the CD player gave out and I was given the green light to "upgrade". So I replaced the door speakers with JBL P532 5 1/4 (Although I now understand that the P-632 6 1/2 will work.) I replace the CD/Radio/Tape system with the Blaupunkt Santa Monica. We chose it for its looks we did not want a flashy deck and I planed on using the 4 line level out puts to run external amps. I chose an ECLIPSE 3640 4 CH amp to drive the door and headrest speakers. (I might have gone with the Clearwater speakers but I did not find a place to get them until weeks later. I may still get the Clearwater headrest speakers, as the Kenwoods are 10 years old.) I also got an ALPINE MRV-100M for the Subwoofer once I found this JL Audio stealth box. So first I had to find a place to put the AMPs and run the wires. I could not believe how easy this all was. I cut a 1/4 inch square of plywood to fit on top of the spare tire. I mounted the ALPINE on the bottom side and the ECLIPSE on the top. The ALPINE (luckily) just fits nicely upside down in the spare tire, this keeps the whole set up from moving around. I ran all the wires under the carpet behind the passenger seat. There is a nice whole there. I put some foam around the wires to keep them from rubbing on the bodywork. It is so nice to have the battery so close to the AMPs it makes for very short power runs.

All this sounded very nice but I needed some base. I did not want to cut up my car. I wanted something that could punch out the sound and look good doing it. The fit and finish on the JL Audio box is out standing and the sound even better. It does require that you drill three 1/2 inch holes in the back deck to keep it from flying around. Read the web page warning.

Using HI-pass crossovers in the AMP I set the headrest to around 300Hz and the door speakers to 150Hz. The LO-pass crossover in the subwoofer AMP is at around 70Hz with a 24db slope. The car has a 90Hz resonance that you want to avoid. This seems to do the trick. I kept the JL Audio box at 6 ohms there was no need to go to 1.5 ohms. I can drown out everything else with the Sub as it is.

The music seems to come from every place in the car. The coolest thing I have found to listen to is a piece of music with lots of percussion. DEAD CAN DANCE with LISA GERRARD, she just won some Hollywood award for her work on Gladiator man what a voice. I first heard DEAD CAN DANCE at a PETER MURPHY concert as intro music. PETER MURPHY another great voice, is outstanding as well. It is like sitting in the middle of the drum set with different drums and symbols and the like. It sounds like they are all around you. This mixed with the vocals and bass guitar can be a very demanding music to reproduce with any clarity. The dace/techno stuff I listen to is easy you just need some good punchy base and a tweeter and you are good to go. (hehehe)

To give you an idea of how well this sounds. I compare every thing to my home system. http://www.martinlogan.com/prodigy_speaker.html and http://www.bkcomp.com/ref.html and http://www.bkcomp.com/stereos.html

I have the 7250 5 CH AMP.

[3/6/2000] Reviewed by: Mykael Freeman - miatamyk@tampabay.rr.com

Applicable to: '90 - '97 1.6 liter

A custom designed sealed bass enclosure specifically for the Mazda Miata. It contains 2 8W6 JL Audio speakers, a pre-wired box, three bolts/washers that secure it from the bottom.

The installation is a pain as you have to set up and drill three holes to secure the box to the car. If you have an '89.5-93 model you need to acquire a cockpit brace bar from a '94+ model. This is easy as many dump them when getting roll cages. Once installed and the cockpit brace tightened back down this box is NOT going to be stolen without doing serious damage to the car and enough to likely render the theft of the box useless. Sound wise the Stealthbox requires LOTS power. I use a Phoenix Gold ZX-250 to power it and it sounds wonderful, clean, clear, and sharp. I also use the LPL (Line Power Level?) controller on the amp as something of a second volume that only controls the Stealthbox. This little feature from Phoenix Gold allows me to enhance the sound of the music playing without overpowering the unit and also to kill the box completely when in residential area's at late hours or when going through area's where advertising the bass is not a welcome idea.

The unit retails for $800 in most places and is not supposedly an internet item. I managed to track down and pick up the unit for $469 new via the internet and had it to my door for $500 even. For $500 it's a fantastic deal! For $800 it's a LOT of money for what you get, but still the only real system for good sound. I have heard the tubes in the trunks, the small enclosures in the trunks, etc. It always sounds like the sound is coming from a car behind you and is more distracting than enhancing. The Stealthbox is only a few inches from your head but never overpowering and usually sounds like you are being bathed in the music. Would I do it again? Yes for $500 but not positive for $800. I have pictures of the unit along with other comments on it via my web-site. This also details the rest of the audio system as well as some changes that needed to be made to accomodate the rest. http://www.geocities.com/MotorCity/Factory/5029/Audio.html

Difficult to remove without leaving damage

[10/25/99] Reviewed by: Jeff Mosier - jmosier@ctlnet.com

Applicable to: '90 - '97 1.8 liter

2 8 inch subwoofers mounted in a fiberglass housing that is made especially for Miatas. It mounts behind the seats under the stabaliser bar

super sound no one would know it's there unless they own a Miata.

Great product

Reviewed by: Tim Denning - psychodrmr@hotmail.com

Dual 8" Package tray mounted subwoofer system.

Installation took about 2.5 hours and was fairly straight forward. The instructions were very detailed and the illustrations were a great help. I have a '91 so I had to purchase the '94 and up brace. Not a problem, but an added expense. This, however, turned out to be a blessing in disguise as it completely eliminated several rattles that my car had gained over the course of it's 140,000 mile life, and made the car feel much tighter as well. The unit integrates itself very attractively with the interior of the vehicle and, quite suprisingly, affords no loss of visibility through the rear window. The Sound? In a word, wonderfull. I'm not a bass freak, I like the music to have the balanced sound that one comes to expect from a high quality home system, with bass that's tight and deep, not boomy and loud. And that's just what I got with this product (plus it's very loud when you want it to be :-)...). Overall, I would rank this product high on my list of audio upgrades to the miata. The only drawback is the added weight and the price. It's a little expensive at $650 bucks but has the quality I've come to expect from JL.

Being an audio freak, I had finally given up on trying to get great sound from my '91. In the course of it's life, my little Miata has seen everything from custom built trunk mounted subs (extremely heavy), to a vain attempt at adding 6X9 woofers behind each seat into the hollow areas on either side of the gas tank. My conclusion was that, indeed, the best sound for this car is the wind as it rushes past your ears. However, when I heard about the new JL's for the Miata, I knew I had to try just one more time. After saving my peso's, I purchased the system at the local stereo dealership and rushed
home to install it. I was a little suprised when I discovered that it had to be mounted to the package tray around the gas tank since I thought the cross brace was all it needed to stay down. On the upside, This makes the box almost impossible to steal, which is a major concern with any audio upgrade. The sound in my miata is now really quite amazing with my Boston Acoustic mid's and highs and the JL Sub driving the Bass. One note, It's a real power hog, so give it plenty. My 500 watt Phoenix Gold can more than handle it, but I'm a little concerned about the factory battery. That always was the weak link in the audio system, and now I'm wondering how long it will hold out. Another slight concern, Will I still be able to put that Hard Dog Roll bar that I've always wanted in now?

Reviewed by: Robert Allen - rja@sun.com

Custom, sealed-box, subwoofer for Model 1 Miatas using 2 8" JL 8w6 dual voice coil subwoofers. These are the top of the line JL subs w/ plastic cones and heavy magnets. The sub box itself must weigh about 40 lbs. If you're a weight fetishist Miatoid you may not be happy with this, but unless you're racing it won't make a difference, and the box needs to be this heavy to control the air pressure this sealed box sub is generating. The box is fiberglass with dark charcoal-grey carpeting which is a close  match for the black Miata interior. The carpeting job is very well done.

Read the other reviews for details I won't repeat here. First, this is a top-quality product in terms of construction and quality of installation instructions (6 pages of instrs. w/ many photos). Installation requires drilling 3, 1/2" holes through your rear package tray area as well as removing and re-installing the side-impact (behind-the-seat) crossbar. The unit is bolted in by reaching into the "tunnels" on both sides of the gas tank from the trunk - you'll need loooong arms, or to crawl headfirst into the trunk to reach the front bolt holes you've drilled, but it's not horribly hard. Or, pay your car stereo dealer to install it, which will also give you a 2 year warranty instead of 3 months. Because 2 of the 3 bolts are through the aluminum package tray it is CRITICAL that you obtain the rear bar that came standard on '94 Miatas before installing this sub - failure to use the bar could result in injury if you were in a severe collision and the sub bolts or the sheetmetal they're anchored in failed. In addition you'll probably get better bass performance with the bar anchoring the sub to the rear deck.

The sub is rated at 400 watts RMS power. I'm powering it with 2 channels of my Aura 475 amp bridged to 160 watts @ 4 ohms, but the sub is shipped wired for 6 ohms so I probably only have about 120-140 watts RMS(you can rewire the sub to 1.5 ohms if your amp can take it). I was concerned that I might not have enough power to keep the sub happy on challenging CD material, but it's not a problem for most sane listening levels, and even some unsane levels - I can easily induce painful Sound Pressure Levels with the power I have, but even then the sound is clean.

JL suggests that you use an amp with a steep crossover of 18-24 db, but my amp has just 12 db and there's no distortion - however my amp is sending just 50 Hz and below to the sub, and 90 Hz and above to the front speakers. Leaving the 40 Hz gap is recommended by JL, so you should be sure you can do something like this with your setup. The nice thing about this sub is that it takes the load off your 5.25 or 6.5" door speakers which reduces the problems with vibration or buzzing in the doors. That plus you get truly great, musical, bass. If you want butt-pounding bass and you have the power this sub will deliver that too (just turn your tone control up). But I use it to provide the low end of the music that you don't get with door speakers alone. Examples of albums I listen to which exercise this sub are:

I'll stress it again so it's clear to you - this sub delivers both the very low frequency stuff as well as the Pop of a bass drum with equal clarity. I payed $700 including tax and installed it myself. The install takes about 2 hours on average if you're handy with tools, maybe a little less.

Oh, three points:

1) don't get this if you have a glass rear window and you want to be able to put the top down - you couldn't.

2) The factory tonneau cover snaps to snaps on the sub box so you can still use it. Instead of it being stepped in however, the tonneau is bulged out (looking sort of like you have one of those roadster hump kits under it). The rear window lays against the convex curved back of the sub when it's unzipped.

3) You can't use the aftermarket window protectors with this sub, but you can still use the center pockets that hang from the factory snaps. One side of the window rests against the carpeted sub, giving it significant protection from scratches, so you sort of get a partial window protector :-).

One other thing for those who wonder, the sub does not noticeably occlude the rear view even with the top up.

Difficult to remove without leaving damage

Reviewed by: Rick Carter - MDColnago@aol.com

A subwoofer system for the Miata specifically

Just to back up the other review of the Stealthbox. The coloring almost matches the black interior of my '94, and people don't realize that I have the speakers there until I turn on the stereo. The two 8" competition level speakers (8W6's) put out a conservative claim of 400 Watts. But they are probably a lot higher than that!

I have an Orion amp that can meet the demands of the Stealthbox, but they kill my Kenwood 6.5" fronts that are running off my Sony head unit. I have to set the gain real high on the front to not get drowned out. But if you feel you can spend the money on the unit (with amp and installation we're talking $1,400.00 here!!), it is well worth it.

Reviewed by: Anonymous Review

Custom made subwoofer containing two competition 8" JL Audio speakers. Mounts on rear deck, held in place by structual bar (1994 or newer) and 3 bolts on base. Does not interfere with top or rear window (if plastic) and is so custom for the Miata it has snaps for the tonneau cover as well.

Although pricey (almost $800 installed), the quality and quantity of sound is unbeleivable. I am using a relatively cheap amp (about 250watts) and the sound is unreal. With the top down going 75 miph ALL you hear is rich deep base. I have MB Quart door speakers and 4" kicker headrest speakers and although this system is not cheap, if you plan to have the car awhile, this sub-woofer is unbeatable. It can be found at the JL Audio web site under "Stealthbox" www.jlaudio.com or in brochures from your local dealer. I just can't emphasize how impressive this thing sounds.

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15 April, 2001