Replacing Alpine Sub with Aftermarket using same housing

treyman

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I am going through the process of adding 2 subs to my JL which has the the 8 inch alpine upgraded system. Bought the drivers side stealthbox and an additional JL 10TW1-2 which is the same sub that's in the stealthbox i ordered. Figured some of you may want to see how I built out the factory sub housing to hold this sub. Photos below.

Since the sub was smaller then the cutout hole for the factory Alpine sub, my plan was to fabricate at least 1 MDF "ring" (found 2 to be the right amount) to mount into the existing 8 screw holes, using the existing 8 screws.
I started by building the first ring which would sit into the recessed slot in the factory housing. I used a 1/4'' MDF sheet to cut this first layer.
IMG_4251.jpg

IMG_4253.jpg

I used the trim ring as outline and then sanded away to get it to fit snug.

I then built a second "ring" to sit on top of this one and fill out the rest of the opening. they are not the same shape as the second layer i wanted to go all the way to the upper edge of the factory box.
IMG_4254.jpg

Then drilled holes and counter sunk the top so that the screws will hold it all together. Missing some photos in the timeline here, but i think you all will understand. Then measured 230 cm hole (matched JL audio hole spec size) cut it out with my jigsaw and sanded some more. I test fit everything many times to make sure i was happy with how they were aligning.

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once i was happy with the fit, spray pained it black and thats where i am at so far. I am still awaiting other parts to arrive from crutchfield and JL including my amp, wiring kit, and the stealthbox for the driverside.

Will add more once it's all in.
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treyman

treyman

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Update: both subs in, Amp mounted under driver seat. all looks factory. very happy with how it turned out.

349423-ce6ce27fc7382f095a5ef2a806904bd3.jpg


Also in is a stealthbox on the drivers side
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Amp went under drivers seat, you can't see it with the seat in my normal driving position.

349426-d2fea3750b1ab7873724a6aa3d682a8f.jpg


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heres the view with seat all the way forward


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ziff73

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how is the sound from the custom mod? any rattles from the factory enclosure? did you put any sound deadener / polyfill?

any chance you want to make a 2nd set!
 

ziff73

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randomly i just ran across your crutchfield review. what did you ultimately do?
 
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treyman

treyman

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sound is great. Added some polyfil hit the back of the plastic with some asfault tape from home depot. Need to hit it more Of both probably as there is a little bit of rattle at very high volume.
If you read my review. I do think when i push the subs I’m melting the voice coil on each. If/ when they blow next subs will be dual voice coils as from my past experience thats the way to go. But that said i have not smelt them since early on. So could have been a break in period. Overall. Way way better sound then the crap factory aline sub. I also replaced all 4 of my 3.5s with kenwood excelons and am very happy with those.
i could make another set if persuaded. As now i have a pretty good template for them. And wasnt all that much work if you have the tools and any woodworking experience.
 

ziff73

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thanks. i have the JL XD700/5v2 and replaced the front and rears with JL c5's. Next on the agenda is what to do with the stock alpine sub, which is currently being driven off the factory amp. The JL amp can drive 300 RMS at 2ohm.

Do i:

a) replace the speaker and do what you did or pull out the enclosure, replace the factory panels/carpets and add stealthbox.
or...
b) keep factory sub and add stealthbox to other side or add a stand alone enclosure resting on the floor.

not sure how i feel about drilling holes into the wheel well (stealthbox directions). thus i though the simplest less intrusive method was to mod the factory enclosure like you did. That being said, i haven't seen that many people do it. Could/would you fit a 12".

i'm fairly handy but don't have a router for the smooth cuts. i'm limited to a jig saw, dremel and
multi-tool.

thx
 
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treyman

treyman

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I dont quite follow your stock amp to factory amp deal. As for the alpine sub. It’s trash. No need to keep it if you are in for an aftermarket sub. Stand alone box in the back will undoubtable be the best sound. But you lose the cargo space. Not a trade off i was wiling to make. As for the steathbox drilling. It couldnt be easier. I drilled, cleaned up any burs and the spray painted the holes so no rust. Also hit them with black caulk When installing the screws/washers etc. Again to resist water. Im not a fan of drilling holes in my car. (I now have 11 i have drilled and clearly remember each one)
A 12 would be real close the way i did mine. And probably would go. I def would have tried if the stealthbox offered a 12 version to make them match But not sure as i didnt try.
sounds like youre doing everything right just need to decide what is most important to you and your rig.
Hope this helps. Happy to offer more of my own opinions if you have more questions.
 

ziff73

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I was just saying the factory sub is still receiving signal from the factory amp whereas the fronts and rears are being powered from the JL amp. The replacement sub will connect to the JL amp.

From what I understand the stock sub is also secured to the back of the panel (in addition to the front mounting screws). Is the new JL sub just secured via the front mounting screws only. Is there enough support?

Yeah I prefer not to lose much cargo space. would you consider making a mount for the same JL Sub replacement?
 

Mattk11

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sound is great. Added some polyfil hit the back of the plastic with some asfault tape from home depot. Need to hit it more Of both probably as there is a little bit of rattle at very high volume.
If you read my review. I do think when i push the subs I’m melting the voice coil on each. If/ when they blow next subs will be dual voice coils as from my past experience thats the way to go. But that said i have not smelt them since early on. So could have been a break in period. Overall. Way way better sound then the crap factory aline sub. I also replaced all 4 of my 3.5s with kenwood excelons and am very happy with those.
i could make another set if persuaded. As now i have a pretty good template for them. And wasnt all that much work if you have the tools and any woodworking experience.
Really nice job with the adapter and that install. Honestly, I'm surprised you can get very good sound with the factory Alpine enclosure because it is so flexible and too small for that woofer. That JL stealthbox is made really well out of fiberglass specifically for that woofer. B ut I always like seeing dual woofers.

Apologies if this it too much info....Based on the amp you have, you have a greater chance of underpowering your woofers with high distortion that you do overpowering them. Distortion is a far worse enemy to your woofer than too much power. It's important that you set you gains properly using an O-scope or distortion detector so you aren't overdriving your amp. You definitely should not be smelling any burning.

A dual voice coil sub does not perform better than the same sub with a single voice coil. Dual voice coil subs are intended to give you wiring options. For instance, 2-ohm dual voice coil sub can be wired as 1 ohm or 4 ohms to match your amp. In my set-up I have two dual 2 ohm woofers wired to 4 ohms each, then combined to 2 ohms to match my amp. The woofers handle 600 watts each but my amp will do 1500 watts into 2 ohms. So a little more power than they can officially handle, but the gains are set so there is no distortion at full volume.
 

ziff73

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what size MDF board is the top layer? looks a little thicker than the 1/4" first.
 

chris1374

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How do you remove the original subwoofer? I removed all 8 of the screws from the grill and then tried prying the speaker out but it just doesn’t want to come out. What else is holding it in?

Thanks for any info!
 

Vandy23

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How do you remove the original subwoofer? I removed all 8 of the screws from the grill and then tried prying the speaker out but it just doesn’t want to come out. What else is holding it in?

Thanks for any info!
You have to take out the entire sub enclosure to get to the screw holding the sub from the back.
 

chris1374

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You have to take out the entire sub enclosure to get to the screw holding the sub from the back.
Thank you so much! I’m glad I didn’t pry any harder. But now I have to ask, how do I remove the sub enclosure? I didn’t quite see a starting point for pulling that out. Thanks again!
 

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sound is great. Added some polyfil hit the back of the plastic with some asfault tape from home depot. Need to hit it more Of both probably as there is a little bit of rattle at very high volume.
If you read my review. I do think when i push the subs I’m melting the voice coil on each. If/ when they blow next subs will be dual voice coils as from my past experience thats the way to go. But that said i have not smelt them since early on. So could have been a break in period. Overall. Way way better sound then the crap factory aline sub. I also replaced all 4 of my 3.5s with kenwood excelons and am very happy with those.
i could make another set if persuaded. As now i have a pretty good template for them. And wasnt all that much work if you have the tools and any woodworking experience.
awesome job do you think instead of wood you can use thick plastic
 

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