# JL Audio Stealthbox Subs Installed in M3 with HK



## Kewl X5 (Apr 6, 2002)

Many props to Technic who did this months ago on his M3 down in Florida. (Check out his original post: http://www.bimmerfest.com/forums/showthread.php?t=74642&highlight=jl+audio+stealthbox ).

Well, I had the "SoCal" version done finally this month. With the help of Technic, he designed a special amp bracket to hold the JL Audio 250/1 amp to the right rear corner of the trunk.

Melvin Tool & Die in Fort Lauderdale, FL (e-mail Todd King @ [email protected]) has the original design and they can make the same bracket if you like. It specifically holds the JL Audio 250 amp.

With the help of Custom Cellular (aka CC Wireless) in Irvine (www.customcellular.com), they helped with the installation of the JL Audio Stealthbox and Amp. If you are in the Orange County area, they can do the same setup (since they already did it in my car). Ask for Bill (949 250-7878).

Bottomline, Technic was right. The M3 with the HK system should have sounded like this from the factory. There is enough sub-bass to enhance your listening pleasure.

The JL Audio subs which are 8" subs replaces the 5" mid-bass HK speakers on both rear corners on the rear deck. The mid-bass is retained by unplugging the "HK Subs" (in reality they are 6x9 speakers) from their amp and sending the signal that was originally meant for the 5" mid-bass to the 6x9 speakers. So you retain the mid-bass, have extra sub-bass ala JL Audio Subs, and the tweeters are still in their stock location in the rear side panel.

I set up the amp to filter cross-over around 60Hz but with a 24dB slope, 48Hz boost around 11-12 dB and turned on the 30Hz filter to prevent damaging the subs since they are free-air subs ported into the trunk space.

The bass is definitely there but without overpowering the stock speakers and actually, it really sounds balanced and nice. Those people looking to waking up the neighborhood need not to apply here.

You can private mail me for more info.


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## jetstream23 (Mar 9, 2004)

Nice! So to summarize, you've added the JL Audio 250W Amp and 2 JL 8" subs which are mounted under the rear deck where the 5" stock speakers once were? If you don't mind, can you give a ballpark total cost on this for equipment and install? Are we talking $1,000? $1,500? etc.

Thanks. It looks great and I'm sure it sounds even better.

EDIT: One more question...You're now sending the signal that was previously going to the 5" mid-bass drivers to the 6x9's. Are those 6x9's two-way speakers? Also, is the signal that's being sent the same midrange signal (say above 60Hz, below 2000kHz) from the HK amp? :dunno:


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## AsianImage (Oct 10, 2004)

I am asusming this can work with my e39 too right?

I would like more info on this as well. That set up is SUPER CLEAN and I bet it sounds great in your car!

Also....any one in So Cal Los Angeles area do this type of install? It looks very clean. :thumbup:

EDIT: I just saw that Custom Cellular is in So Cal...would they be able to do the whole install or just the boxes? Would you recommend them? TIA!


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## Technic (Jun 24, 2002)

Kewl X5 said:


> Many props to Technic who did this months ago on his M3 down in Florida. (Check out his original post: http://www.bimmerfest.com/forums/showthread.php?t=74642&highlight=jl+audio+stealthbox ).
> 
> Well, I had the "SoCal" version done finally this month. With the help of Technic, he designed a special amp bracket to hold the JL Audio 250/1 amp to the right rear corner of the trunk.
> 
> ...


I'm very happy that _you_ are happy with that set up... that is an excellent audio upgrade for E46's. :thumbup:


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## Kewl X5 (Apr 6, 2002)

For the E46 3-series, the JL Audio Stealthbox are about $400-450, the JL Audio 250/1 amp is about $300....You could probably do the install yourself, but it will probably cost about $200 for the install. You can go to www.jlaudio.com and look up stealthbox for more info...they have PDF files you can download.

The 6x9s in the E46s are NOT two-way...basically a great mid-bass driver....BMW/HK decided to make those as "subs". The tweeters for the rear in the E46 coupes are in the rear side panels....above the rear side armrest. In the 3-series sedan, the 6x9 are on the far back rear corner (look in your trunk), but I don't remember where the mid-bass and the tweeters are, but they are separates on the rear last I remembered.

So, yes, I took the signal that originally was going to the 5" mid-bass driver and instead sent it to the 6x9s and also use that same signal to tap into and using a Peripheral SuperVendetta Hi-Lo converter to convert it to a low-level signal for the 250/1 amp. To answer your question, I adjusted the amp's crossover to blend in the subwoofer. I did it by ear.

This is by far the nicest upgrade without taking too much trunk space.

Ask Technic or I for more info.



jetstream23 said:


> Nice! So to summarize, you've added the JL Audio 250W Amp and 2 JL 8" subs which are mounted under the rear deck where the 5" stock speakers once were? If you don't mind, can you give a ballpark total cost on this for equipment and install? Are we talking $1,000? $1,500? etc.
> 
> Thanks. It looks great and I'm sure it sounds even better.
> 
> EDIT: One more question...You're now sending the signal that was previously going to the 5" mid-bass drivers to the 6x9's. Are those 6x9's two-way speakers? Also, is the signal that's being sent the same midrange signal (say above 60Hz, below 2000kHz) from the HK amp? :dunno:


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## Kewl X5 (Apr 6, 2002)

As far as I know, JL Audio does not make stealthbox specific for the E39, but it doesn't mean it couldn't be done. You can probably custom intall a free air sub and do something similar. Yes, the sound is clean and you can adjust the bass to make it sound boomy to clean and tight based on the AMP crossover and low frequency boost knobs.

Technic, any advise for this person? :dunno:

You can call up Custom Cellular. I just had them order the parts and put it in. The installer did a great job.

They do upgrades with Bluetooth, radar detector, and stereos in BMWs all the time!



AsianImage said:


> I am asusming this can work with my e39 too right?
> 
> I would like more info on this as well. That set up is SUPER CLEAN and I bet it sounds great in your car!
> 
> ...


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## Technic (Jun 24, 2002)

AsianImage said:


> I am asusming this can work with my e39 too right?
> 
> I would like more info on this as well. That set up is SUPER CLEAN and I bet it sounds great in your car!
> 
> ...


Unfortunately, there are no Stealthboxes for E39's...


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## icemanjs4 (Dec 1, 2004)

Hey KewlX5,

I'm going to revive an old thread. It's been a while since you did the subwoofer upgrade. Are you still happy with it? How much did the setup cost you? I'm debating about upgrading the audio in my 2005 330i.


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