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albersondh
01-15-2009, 08:24 PM
I’m trying to save as much internal space as possible (I sleep back there), so that’s the purpose of this box. Crutchfield has a similar box that goes for $250, I can’t remember the specs on it but I think it’s for a single 10" woofer. After taking a bunch of measurements I decided that there is no way you could fit a decent 10" sub in this area due to the lack of mounting depth. Maybe if you stacked the MDF up super thick it work but that would look like ass. So I decided to make a sealed fiberglass box for a "good" single 8". Ill be using a JL 8W3v-4. The mounting depth on this sub is pretty close to the space limitation in this area. Using 3/4 MDF for the face of the box helped me to get pretty close to 5" but still not quite enough for my Fosgate HX2 10". Not to mention I would have had to cut out a bunch of the internal body metal to get the diameter for the 10" bucket.

First I cut out the interior panel to make room for the box and to give me the base of my mold.
http://i151.photobucket.com/albums/s150/albersondh/DSC04278.jpg

Here I’m finding the max mounting depth I can get away with.
http://i151.photobucket.com/albums/s150/albersondh/DSC04279.jpg
http://i151.photobucket.com/albums/s150/albersondh/DSC04280.jpg

Now with a pretty good idea of my max depth I went ahead and made a mold for the fiber glass. I used the piece I cut out and then spaced it out with wood pieces I had laying around. I traced out the front piece of the mold that I had cut out of the interior and made the back side of the mold out of OSB.
http://i151.photobucket.com/albums/s150/albersondh/DSC04281.jpg
http://i151.photobucket.com/albums/s150/albersondh/DSC04282.jpg

Verifying my final mounting depth. I gave myself a bit of space so there is no way the box will contact the inner body panel.
http://i151.photobucket.com/albums/s150/albersondh/DSC04283.jpg

Then I covered the mold frame with seranwrap. I used some news paper to make a hump where the backside of the sub is going to live. I also used the newspaper to build a contour that follows the inside of the body panel just to gain as much air space as possible for optimum sub function. Once my mold was all set up and pulled tight with the selifane I covered the whole thing with tin foil, sprayed it down with WD40 to keep the fiberglass resin from sticking to the mold. Then I laid the fiber glass. I did about 3-5 layers of fiberglass cloth which is most likely over kill but that’s how I roll. Once the glass is all set up and tacks off I had to cut the whole thing in half to pull out the mold.
http://i151.photobucket.com/albums/s150/albersondh/DSC04285.jpg

Then I put the box back together and glassed it all up shut again with another 3-5 layers of cloth.

Initial fitment was right on.
http://i151.photobucket.com/albums/s150/albersondh/DSC04286.jpg

So I welded up some spacers with 5/16id tube and some 5/16 nuts welded to both ends. I made three spacers then I drilled out the internal body metal and bolted in my spacers. Then I made a cardboard template to get the location of the spacers and OD of the final MDF mount correct. Used my template and traced out the final 3/4 MDF face/mount.
http://i151.photobucket.com/albums/s150/albersondh/DSC04287.jpg

I used some stainless button heads for securing the MDF onto the mounting spacers.

Along the way I also installed a flush mount speaker wire connector to the top of the box and I secured the MDF to the fiberglass box with some screws. I sealed the MDF to the box with some silicone and also sealed the speaker wire connector to the box with silicone.

I’m currently waiting on my sub to come in the mail. Once I get the sub Ill finish up by cutting the hole for the sub and mounting it to the MDF. I will then cover the whole abomination with some carpet. Ill get some pics of the mounting spacers and the speaker wire connector once I get my sub. Want any other pics or information, just ask.

This is my first time EVER doing anything with fiberglass and other than the tremendous patience required it was not a big deal....

BigDaveZJ
01-15-2009, 09:00 PM
How did you seal the fiberglass to the mdf, or did I just miss that part?

haymaker
01-15-2009, 09:45 PM
Very nice write up man! Have you seen those shallow mount 10's? I bet one of those would work. I know 8's can beat but I dunno I just think a 10 would be much better. Have you thought about that option or is it too late to turn back from an 8 now?

http://www.sicorpusa.com/audio/Pioneer/TS-SW1041D/TS-SW1041Dimage2.jpg
http://www.sicorpusa.com/audio/Pioneer/TS-SW1041D/TS-SW1041Dimage5.jpg

this is just one example many other brands offer shallow mount subs as well.

albersondh
01-15-2009, 11:26 PM
How did you seal the fiberglass to the mdf, or did I just miss that part?

The front side of the fiberglass box that the MDF mounts to is very flat. I let the first couple layers of cloth set up with the front side face down on a flat surface. So when the MDF is mounted to the front of the box (4 screws) I just sealed the circumference of the of box to the MDF with a judicious amount of silicone.





Very nice write up man! Have you seen those shallow mount 10's? I bet one of those would work. I know 8's can beat but I dunno I just think a 10 would be much better. Have you thought about that option or is it too late to turn back from an 8 now?

this is just one example many other brands offer shallow mount subs as well.

I set out with the idea of doing a 10". The pic of the box mounted and installed has a 11" circle drawn on it (see pic above). Take about an inch off that circle and you have a pretty good idea of how much space the mounting hole for a standard 10 would take up. After measuring everything I decided that it may be possible but far more difficult and you would most certainly not meet the air space requirement for a decent 10. Perhaps a shallow mount 10" would work. My Fosgate HX2 10" (a good 10) has about a 6" mounting depth. So I would have had to use about 1.50" of MDF just to gain the space required to meet the bare minimum of the mounting depth requirement. Even with a shallow mount 10 you would almost certainly have to trim out some of the internal sheet metal to get the basket to fit correctly. I figured a really good 8" with plenty of power will work out fine. I think a really good 8 will outperform an ok 10 but that’s just me. I want some bass but it’s not like I’m trying to build a competition grade system. I need to save my money for the Claytons.

ATL ZJ
01-15-2009, 11:27 PM
This is going to show just how little I know about audio, but it would seem that as the diameter of the woofer increases, so should the volume of air inside the box. Is there a minimum box volume that can adequately support an 8" sub? If so, is the minimum volume needed for a 10" sub greater than for an 8"? Is there a case where, given the same small volume of air, an 8" sub will perform better than a 10" sub in the same box?

albersondh
01-16-2009, 12:08 AM
This is going to show just how little I know about audio, but it would seem that as the diameter of the woofer increases, so should the volume of air inside the box. Is there a minimum box volume that can adequately support an 8" sub? If so, is the minimum volume needed for a 10" sub greater than for an 8"? Is there a case where, given the same small volume of air, an 8" sub will perform better than a 10" sub in the same box?



Sub manufacturers have the recommended air volume advertised with there specs. Generally as the woofer size goes up so does the air volume requirement due to the added displacment. There are many other factors that add into the final recommended air requirement most namely are power handling and materials. There are formulas for figuring how much air volume you have but they work best for simple boxes that don’t have odd shapes and contours. I didn’t use anything to figure out my volume I just made it as big as possible without having to do any body sheet metal removal. The sub I selected needs .3 cubic feet of volume for ideal sound. Ported boxes require a bit more space than sealed. I think I’m pretty close to recommended space requirement. There is a window of ideal performance that can be obtained with an appropriately sized enclosure. Having a good woofer and a good power supply will allow for some adjustability/flexibility within the air space you have. I wouldn’t say that it is entirely critical to meet the ideal space requirement as long as your components are of good quality and you are at least close to the required space requirement.

An 8 in an ideally sized enclosure running at peak RMS power should always outperform a similar/same model 10 in a inappropriately sized enclosure running its peak RMS power. You would be amazed at how loud and low a “good” single 8 will perform.

To make a shallow mount 10 the manufacturer is having to limit the size of there magnet. This essentially limits the potential for electromotive force to be applied to the cone via the voice coil. To get the cone moving and making sound with a smaller magnet the manufacturer has to use more flexible materials in the cone design. This is the trade off for the shallow mounting depth. It will almost certainty not have as much sound producing movement as a normal sub and therefore will not be physically capable of performing like a normal sub with a huge magnet. Im no expert either but this is how understand things to work.

paulkeith
01-16-2009, 12:31 AM
cam,

depends on the sub. manufacturers will specify their recommended volume ranges for each sub they produce. Depends on capabilities of the sub in both power and excursion the suspension is capable of. Some subs are designed to be small volume, some are designed to be large, some are designed as infinite baffle (basically just mounting it in a flat plate...ie speakers in the doors)

albersondh,

Nice work. I've used packing peanuts to measure glass box volumes before. fill it till its full, then transfer the peanuts to a package, measure the depth of the peanuts in the package and you can get a (very) rough idea of your volume. did this with my eD 11ov.2 in a glass box in my old m3.

DJJordache
01-16-2009, 09:59 AM
I tried something like this but will have to get the pics off my home computer to show

albersondh
01-17-2009, 07:56 PM
cam,

depends on the sub. manufacturers will specify their recommended volume ranges for each sub they produce. Depends on capabilities of the sub in both power and excursion the suspension is capable of. Some subs are designed to be small volume, some are designed to be large, some are designed as infinite baffle (basically just mounting it in a flat plate...ie speakers in the doors)

albersondh,

Nice work. I've used packing peanuts to measure glass box volumes before. fill it till its full, then transfer the peanuts to a package, measure the depth of the peanuts in the package and you can get a (very) rough idea of your volume. did this with my eD 11ov.2 in a glass box in my old m3.

Thanks. I learned ALOT building this POS. Im sure the next one will look/work much better.I just got the 8 in the mail. The specs that come with the sub convert the air volume to liters and it calls for 8.5L on a sealed enclosure. I guess Ill be filling it with water before I cut the big hole in it just to see how close I am.


Now if I could find a good 5 channel that would fit under the back seat.... I measure about a 20" x 11" max space under the back seat. All the 5 channels I like are 22"+L and over 11.5"+W. I can’t run two amps under the seats because the 2500W inverter will live under the other back seat. I may just run a good sub amp (500W) and see how well the head unit works (25W x 4). I’m looking for clean sound with nice freq overlap, not mind numbing bass drowning out my mid's/hi's.

Edit: I like this amp: http://www.sonicelectronix.com/item_9144_Kicker+MX700.5.html
It’s just a bit too big on the long side at 20 1/16" but I think I can work with that. It’s about what I want as far as power and it’s designed for Marine application which is a huge plus considering where it is going to live. The only draw back is that I can’t find any reviews on it so if I decide to pull the trigger on thing Ill be the lab rat....

albersondh
01-18-2009, 05:28 PM
I’m out finishing up my box (pics are in route). I came up with 11 liters of volume in the box. So I’m wayyyy to big for the 8.5 liters that the 8" spec sheet calls for. So I’m coming up with ways to lower the box volume which won’t be an issue. I guess it’s a good thing it turned out too big rather than too small.

All this extra volume got me thinking about a 10" again. After I cut out the hole for the 8" I re-measured everything and it turns out a "good" 10 will fit (barley). So I looked up the specs on my spare 10's (HX2's). In a sealed box they call for .2-.75 cu.ft of volume. I found this calculator that does a nice job of converting volume: http://www.lenntech.com/unit-conversion-calculator/volume.htm
It turns out I’m within the OE recommended spec for volume on my 10".... A bit close to the low side at .388 or 11 liters, but it is doable. So I was wrong, and I retract any statements I made about a 10 not working.

For my purposes I’m going to stick with the 8. This is due to the power requirements of the 10. I want to run a 5 channel amp and I can barley find one that will fit under the back seat and properly power the 8, so forget about powering the 10. You would need to run two amps under both back seats to run a 10 in this enclosure. This may not be an issue for most but I need that space for a power inverter so I’m stuck with the 8.... Ill get over it.....

paulkeith
01-19-2009, 12:26 AM
just measure out pieces of 2x4 that equal out the volume that you need to subtract and glue them inside the enclosure.

I run a 5 channel in my F-250, but like you said its about 12"x20"x3". I have the sub channel run down to 2 ohms, front comps running off 2 of the channels, and the head unit powering the factory rear door speakers.

albersondh
01-20-2009, 12:19 AM
just measure out pieces of 2x4 that equal out the volume that you need to subtract and glue them inside the enclosure.



I started using 2x4 but then I decided I wanted to keep it light. So I used some hard foam bricks covered in masking tape then coated with resin to seal them up. Yea the 2x4 would have worked fine though.

Anyways, here we go with the rest of the pics:


These are the spacer/mounts I whipped up that secure the MDF to the inner body panel. Of course I ran out of gas while I was welding these so that was a real hoot. Someday Ill just break down and spring for an 80cu.ft tank....
http://i151.photobucket.com/albums/s150/albersondh/DSC04290.jpg
http://i151.photobucket.com/albums/s150/albersondh/DSC04289.jpg


Initially this is how I determined the box volume.
http://i151.photobucket.com/albums/s150/albersondh/DSC04291.jpg

Then I pulled my head out of my ass and resined up the MDF so I wouldn’t water log it. This is me re-checking the volume as I’m adding junk to take my box volume down to the factory spec of 8.5l. Then I siphoned out the water.
http://i151.photobucket.com/albums/s150/albersondh/DSC04295.jpg



Cutting the mounting hole for the sub. I used a Bosch Rotozip with the hole cutting attachment.
http://i151.photobucket.com/albums/s150/albersondh/DSC04292.jpg
http://i151.photobucket.com/albums/s150/albersondh/DSC04293.jpg

These are the foam bricks covered in tape/resin that I used to lower my volume.
http://i151.photobucket.com/albums/s150/albersondh/DSC04296.jpg
Bricks installed.
http://i151.photobucket.com/albums/s150/albersondh/DSC04297.jpg

Then I used some high pile polyfill and covered the inside.
http://i151.photobucket.com/albums/s150/albersondh/DSC04298.jpg


Covered the out side, cut the seal area for the sub out of the carpet, and wired up the sub.
http://i151.photobucket.com/albums/s150/albersondh/DSC04299.jpg


I cleaned the sealing area for the sub very well and I did a light coat of Vaseline for good measure.
http://i151.photobucket.com/albums/s150/albersondh/DSC04300.jpg


Ran the sub wire under the rear d/s seat and in she went.
http://i151.photobucket.com/albums/s150/albersondh/DSC04301.jpg


The money shot.
http://i151.photobucket.com/albums/s150/albersondh/DSC04302.jpg


I have a heavy metal protective basket on order to keep the cone safe. The amp is also on order but once I have it I still have issues preventing me from hooking the system up. I won’t run the stereo power off of the main battery. I’m doing a dual battery with relay isolation here pretty soon. Before I can do that I have to yank the OE air box. So I’m thinking a snorkel may be in my near future.

1. Snorkel
2. Dual battery
3. System

albersondh
03-09-2009, 01:02 PM
Reporting back on the performance of this little sub enclosure I made up. I finally got my dual battery system done, so in went the system. Im running one 5 channel 1000W kicker Marine amp in the OE amp location. Replaced the OE 6.5" mid/hi's with some 2 ohm infinity kapa's. Holy SHIT!!! This one little sub is WAYYYY the hell more bass than I will ever need. If ever I had any doubt in the power of intelligent engineering, over brute force, that doubt is gone. This thing thumps as hard as systems I have heard with a decent set of 10's and twice the power Im sending to my single 8" sub. Of course a well engineered/built system with 10's would kill this thing, but at well over double the cost, and at an enormous loss of interior space. My little 8" takes up no space at all. If you want stupid amounts of sound but don’t want to sacrifice the space, build one of these, you will NOT be disappointed.

froggo27
03-09-2009, 01:26 PM
Sweet build! Build one for a WJ and send it over. :D

AgitatedPancake
03-09-2009, 03:04 PM
the WJ has some little cross supports in the same area that need to be cut out to do similar, I'm tinkering with the idea of trying to stuff my MTX T9515-44 half way into the body like that. Damn thing is 11" deep.

SirFuego
03-09-2009, 04:42 PM
That fender area was a major rust spot on my ZJ -- to the point where I could stick my entire hand through the fender. It looks like yours is pretty clean, but I would keep close tabs on it being that you are in Detroit (where I assume rust can eventually be a problem).

albersondh
03-09-2009, 09:24 PM
the WJ has some little cross supports in the same area that need to be cut out to do similar, I'm tinkering with the idea of trying to stuff my MTX T9515-44 half way into the body like that. Damn thing is 11" deep.


Thats tough, 11" deep.... Anything can be done but I think you will have to stand it off at least a couple inches. IMO its still worth it to use that space vs. taking up all your cargo area.


That fender area was a major rust spot on my ZJ -- to the point where I could stick my entire hand through the fender. It looks like yours is pretty clean, but I would keep close tabs on it being that you are in Detroit (where I assume rust can eventually be a problem).

My ZJ is from Nevada. I picked ut up when I got of the Corps back in 05. Its only seen 2 MI winters, but yea, Im keeping close tabs on the rust. So far Im rust free but I know its just a matter of time....

AgitatedPancake
03-09-2009, 10:45 PM
Thats tough, 11" deep.... Anything can be done but I think you will have to stand it off at least a couple inches. IMO its still worth it to use that space vs. taking up all your cargo area


Oh yeah I don't expect to be able to fully sink it in, I want to go as far as I can. Then at however far out the sub mounting surface is make a new wall for the sub to mount to, and possibly also make it a storage box that goes all the way to the back of the seats.

adgroza
03-16-2009, 10:01 PM
do you have any better pics of making your mold? im a little confused as to what you actually did with all that osb and mdf you had. do you have any idea how much you could have lost depth wise to avoid useing your filler?

albersondh
03-16-2009, 11:10 PM
do you have any better pics of making your mold? im a little confused as to what you actually did with all that osb and mdf you had. do you have any idea how much you could have lost depth wise to avoid useing your filler?

Making the mold is really very simple. Cut out the piece in the location you want to stuff the box into. Use the piece you cut out as the foundation for your mold. In pics 4 and 5 (down from the top) you see me fooling around with the OSB. All I’m doing here is cutting out a piece of OSB in the same shape of the mold, and using it to space out, or widen the mold. I could have just as easily used only the piece I cut out for my mold, but I wanted maximum mounting depth. For more info on working with glass or doing a mold relief go to Google. You will end up completely enclosing the mold with glass, so eventually you will have to cut it in half, and then re-seal it.

I’m totally guessing here, but I probably could have made it .5-1.0" thinner and still had the correct volume for my sub without the filler blocks, but then it wouldn’t have fit because the box wouldn’t have been wide enough.



This was the first thing I have EVER made of fiber glass and I think it turned out well. Using the manufacture specs on enclosure volume is a must for me now. In fact I will never buy an “off the shelf” enclosure again, now that I know the level of performance that can be gained from a well engineered/balanced approach. My single 8” will make you pee blood and leave you looking for the huge ban-pass box with the 10’s in it.

adgroza
03-17-2009, 08:46 PM
ok thanks! that makes a little more scense now! that sounds like WAY more sound than what i want, but is just what i was thinking to do, just didn't know where to start! i've worked with glass a million times b4 in the shop, but never made anything totally from scratch like that. mostly just repairs to running boards and ricer bumpers and what not. thanks for the write up!

SkZj
03-25-2009, 12:06 AM
Your post inspired me, so I made my own. Spec'd it for the same sub, as thats all that really fits, and sounds decent in such small airspace. I also had the benefit of having a shop full of tools, and installing car stereo's for a living. :D

http://members.shaw.ca/sejamis/hatchafter.jpg

adgroza
03-29-2009, 08:58 PM
any pics of your build skzj? how is yours attached/fastend? did you make your mold the same way?

DUBYA J
07-04-2009, 08:08 PM
Sweet build! Build one for a WJ and send it over. :D

i would buy one for sure!! please let me know if you make one

ricky51barth
02-04-2010, 03:37 PM
i have a quick question can i monut my amp under the back seat or is that too hott

dp96zj
02-04-2010, 03:41 PM
i have a quick question can i monut my amp under the back seat or is that too hott

yes, that's where most people put them.

http://www.jeepsunlimited.com/forums/forumdisplay.php?f=13

Newell1225
02-04-2010, 10:15 PM
my 1000 watt amp never has any troubles.. its under the passenger side (the 40 of the 60/40) seat..

DrumBoy
04-01-2010, 12:55 AM
my 1000 watt amp never has any troubles.. its under the passenger side (the 40 of the 60/40) seat..

What make/model is your amp? I am looking for a new one that would ideally fit where my Infinity is now.

-DrumBoy

DrumBoy
04-01-2010, 01:05 AM
http://i151.photobucket.com/albums/s150/albersondh/DSC04302.jpg
I really like the flush look of your enclosure. Let me know if you ever are into making any more.

-DrumBoy

DJJordache
04-02-2010, 08:57 AM
yeah that looks good and is much lower profile than the JL audio steathbox

albersondh
04-05-2010, 07:38 PM
http://i151.photobucket.com/albums/s150/albersondh/DSC04302.jpg
I really like the flush look of your enclosure. Let me know if you ever are into making any more.

-DrumBoy

I would build more, if there was enough interest. You wouldnt be interested in my price if I was just building one, but if I were doing like 5.... I can spec the box out for whatever 8", but I highly recommend the W3. I suppose I could even do them for a WJ. The way this box is secured and the fact that it was engineered spicificaly for the speaker it houses, makes it sound better than most comprable boxes I have heared. Its tight, loud, and deep enough to make people look for the 10's.

WJJEEPIN
04-06-2010, 11:57 PM
I went with the external MDF frame with fiberglass backing moulded to the corner with enough room to open lid for spare.

http://i133.photobucket.com/albums/q51/btwnmak/Misc%20Jeep%20Pix/MALL%20CRAWLIN/IMG_4979.jpg

DerekL
04-11-2010, 06:59 PM
hell heres my wk one for gigs and shits...
http://i175.photobucket.com/albums/w139/blacksheep753/006.jpg
MDF with fiberglass over the hump sooner or later gonna fiber it into the rear hatch...

downtowncb
04-11-2010, 11:58 PM
Here is mine in my ZJ.

http://i34.photobucket.com/albums/d133/dtcb70/New%205_9L/IMG_1990-1.jpg

I added padding to the storage area and nothing rattles.

http://i34.photobucket.com/albums/d133/dtcb70/New%205_9L/IMG_1993-1.jpg

dp96zj
04-12-2010, 12:33 AM
Guess I'll throw mine in. My initial plan was to have it on the side of the cargo area like the above pics, but I ended up going the easy way out. I made is specifically for the displacement of this sub, so it's just big enough to get the job done, with no excess space. The back of the box is angled to run parallel with the seat, so it sits nice and snug. Filled it with fiberglass insulation, it sounds great!

http://i248.photobucket.com/albums/gg186/dp91990/MC%20Pics/My%20Thread/10.jpg