[cybercop]

Please bear with me as this is my first Fiberglass enclosure.

the red box will be recessed into the door 2.5" after i cut some of the door skin out of the way. I will also have to cut thru some of the bracing, but will find some way to reinforce those areas. I am hoping to get 1/4" thick fiberglass.

The blue box is 11" x 17" x 2.5" outside dimension. I can make that out of either 3/8" MDF or I guess I could fiberglass that as well. I would like to keep weight down.

Hopefully the overall volume will be .35 cubic feet for a Alpine SWR-8D2.

My question is how to outline the inside of the opening I am cutting out so that I can lay the fiberglass matting and have it keep the form?

Also, should I use 3/8" MDF for the outside box and attach it to the fiberglas mold, or should I build a frame and fiberglass the outside box as well?

What suggestion would you have for attaching this box to the door frame?

Any other suggestions before I take on this build?

 

[shutmdown]

i would use chipboard to create the inside frame/shape. To attach it to the door skin I'd use rivnuts.

 

[ndm]

Please bear with me as this is my first Fiberglass enclosure.

the red box will be recessed into the door 2.5" after i cut some of the door skin out of the way. I will also have to cut thru some of the bracing, but will find some way to reinforce those areas. I am hoping to get 1/4" thick fiberglass.

The blue box is 11" x 17" x 2.5" outside dimension. I can make that out of either 3/8" MDF or I guess I could fiberglass that as well. I would like to keep weight down.

Hopefully the overall volume will be .35 cubic feet for a Alpine SWR-8D2.

My question is how to outline the inside of the opening I am cutting out so that I can lay the fiberglass matting and have it keep the form?

Also, should I use 3/8" MDF for the outside box and attach it to the fiberglas mold, or should I build a frame and fiberglass the outside box as well?

What suggestion would you have for attaching this box to the door frame?

Any other suggestions before I take on this build?

MDF does not belong in a door that is exposed to the elements. I would use a plywood. I am a fan of baltic birch. You can get it in 1/4 sheets at my locak menards or special order thicker stuff. Then protect the Plywood with some resin to kind of waterproof it.

 

[cybercop]

NDM,

Are you talking about being exposed to the elements while the door is open in, lets say, rain? That is a GREAT point. Didn't think of that. Appreciate that input.

Would you use the hardwood plywood instead of Fiberglassing it?
Would I have to use a thicker plywood than 3/8"?

 

[jtaudioacc]

what door is that? rear barn door or something?

 

[SHAGGS]

Yeah, IIRC, it's a Rover Discovery rear hatch.

You can use cardboard to create the cavity shape.

As for the build strategy from there, I guess that depends on how you plan to blend it into the trim panel. Assuming you plan to do so.

The cavity and the base, can be done at one time.
The sides can be made from ply, and be essentially a frame around the edges, that is later attached to the base.
The front panel can be flat, or contoured via a mounting ring and fleece/fiberglass. Your choice.

A pic with the panel in place might help visualize how the panel could/will interact with the enclosure.

If you are willing to try your hand at fiberglass, I'd hate to see a square, uninspired front to the box.
Something with some soft transitions into the interior panel would look best, but may be out of your ability range.

And yes, Rivnuts are the best way to attach it to the door.

 

[cybercop]

Yeah, IIRC, it's a Rover Discovery rear hatch.

You can use cardboard to create the cavity shape.

As for the build strategy from there, I guess that depends on how you plan to blend it into the trim panel. Assuming you plan to do so.

The cavity and the base, can be done at one time.
The sides can be made from ply, and be essentially a frame around the edges, that is later attached to the base.
The front panel can be flat, or contoured via a mounting ring and fleece/fiberglass. Your choice.

A pic with the panel in place might help visualize how the panel could/will interact with the enclosure.

If you are willing to try your hand at fiberglass, I'd hate to see a square, uninspired front to the box.
Something with some soft transitions into the interior panel would look best, but may be out of your ability range.

And yes, Rivnuts are the best way to attach it to the door.

I definitely plan on not making it look like a square box, but at the same time want to protect the very minimal volume I am trying to get. Any advice here would be great!

I would also love any advice on transitioning to the panel.

I will get some pics later and post them to get the advice.

 

[ndm]

NDM,

Are you talking about being exposed to the elements while the door is open in, lets say, rain? That is a GREAT point. Didn't think of that. Appreciate that input.

Would you use the hardwood plywood instead of Fiberglassing it?
Would I have to use a thicker plywood than 3/8"?

The doors are a bad place for all things that degrade with water.

If the surfaces will be flat I would use plywood coated in either resin or truck bed liner. I prefer the resin because it can seep into the wood to keep out moisture. Hell If I was doing it I would do both resin and bed liner. I think that the thickness of the ply depends on the amount of stress it will incur. If it is just for mids/small subs I think with proper bracing you could get away with 3/8 but I would rather do 1/2.

On another note...I am not a fan of cutting out that much metal in that kind of area. My wife was recently T-boned and after looking at the results of that accident, I will stay away from those type of areas with my metal cutting tools. Now I did cut metal out of the cargo floor of my Jeep but that is only because the area was surrounded by other much more solid structures and braces. I also have the factory tow hitch assembly between the sheet metal and a potential rear end strike. EDIT!! I just read that this is a rear hatch door....proceed with the metal cutting tools!!


BTW....any reason why you are not going with a simple Infinite baffle setup? Much more simple, much less cutting needed and you are still going to need deadening with either route.

 

[cybercop]

Can you suggest a IB subwoofer? The only one I could find to fit my needs was the JBL GTO804 but I can't find it anywhere.

 

[cybercop]

As promised, here are the pics of the back with the panel on


Up close of current stock subwoofers


Stock subwoofers removed
Subwoofers removed

This is why I can't "Just put a box in the back"

 

[ndm]

As promised, here are the pics of the back with the panel on


Up close of current stock subwoofers


Stock subwoofers removed
Subwoofers removed

This is why I can't "Just put a box in the back"

WOW....
If it were me, I would take that entire panel out, use it as a template to transfer to a 3/4 inch plywood base. Transfer all the mounting locations to the new board and procede to mount a fricking 12inch on that door. Build it out of mostly fiberglass to keep the weight down and make it as curvy as possible to maintain strength. . If you need a little space for the depth of the magnet you could use that area that you were already going to cut out.

You have a few things working to your advantage....Flat door is the main one to me. I mean WOW. If my doors were flat like that I would crap myself with joy!

Hell, you could do one of the JL flat subs or even two tens.. Jeez. I wish you knew how easy that location could be.

You would have to maybe make a way to relocate the door release latch but I see a very clean drawing board there.

 

[Orion525iT]

So this is a bit complicated, but it is what I did to make sealed door pods for my midbass (untreated cones) which maximized volume.

First I cut a hole in the sheet metal for the sealed box. You can see that the hole in the door panel is different from the hole in the sheet metal, and then the edge of the window also creates another contour. The block of wood is just a spacer.

What I did next was I cut pieces of card board and hot glued them together to form a box shape that would slide into the door card, the sheet metal and also clear the bottom of the window.

One finished with the card board shape, I gently pulled the box apart, and used the pieces as templates to transfer to 1/4 plywood. The curved ends are sono tube with the wax paper layer removed. Everything was stuck together with body filler. The plywood was bent by hand where possible for some of the contours, while the lowest bend piece was actually kerfed and filled. Left and right sides are in the picture. There was a lot of clamping and cursing required in these steps.

After the boxes were partially assembled, I brushed them with epoxy (same epoxy I used for laminating) and allowed it to soak in a bit. Once the epoxy was at a green stage (not tacky but still flexible), I laminated 2-3 layers of 7781 E-glass with epoxy. This step allows for good crosslinking of the partially cured brushed on epoxy and the laminated fiberglass.

This pic gives an idea of how the boxes fit into the doors.

Some bracing was added. Acoustic foam line the sides. Volume was around .16 cu ft, which was perfect for my target Q and roll off of the drivers.

I then decided to make the door pockets fit the new speaker boxes. Foam is just for a mold, epoxy was again use throughout.

To attach the pods to the doors I built flanges that molded to the contours of the door sheet metal and the pods. I placed down blue tape, then waxed over that, so that the parts would separate easily, before building the flange (again with epoxy).

Here you can see how crazy and convoluted the final shape. No way I could get the volume I needed by any other method and have the drivers sealed and protected. Flange can be seen around the edge at the top.

Box from the front. I have started some cosmetic filling with epoxy. Part of the mounting flange can be see at the bottom.

The thing with the way I did this is that the boxes can be mounted with the flanges by using hardware or adhesive. I may end up using adhesive to help dampen some of the box resonance from the door. The cut in the sheet metal to accommodate the boxes weakened the door panel, but it will actually end up much stronger than stock once the box is secured into place, especially since the flanges are molded directly to the existing sheet metal.

Its a crap ton of work, but worth it. Hope this gives some ideas.

 

[ndm]

Just looked again...the door release is a cable so it can be moved anywhere that the cable would reach.

You have it SOOOOOOOOOO easy right there. I mean that would be a really simple door build.

 

[cybercop]

Orion, Nice build up! Definitely got some ideas from that. Thanks

NDM, I wish you were in the Atlanta area. Could use some of your skillz! Three different shops looked at this, all wanted to do basically what I am considering, and wanted over $600 just for the box build. None suggested what you are saying.

I can't make the box any deeper than 3" from the panel of the door due to the jump seats.

IB was suggested. Can anyone recommend a IB that has no deeper than 3 1/2".

 

[ndm]

Orion, Nice build up! Definitely got some ideas from that. Thanks

NDM, I wish you were in the Atlanta area. Could use some of your skillz! Three different shops looked at this, all wanted to do basically what I am considering, and wanted over $600 just for the box build. None suggested what you are saying.

I can't make the box any deeper than 3" from the panel of the door due to the jump seats.

IB was suggested. Can anyone recommend a IB that has no deeper than 3 1/2".

My parents own a big ole home in powder springs....

Seriously though i could sink a 10w6 or 12w6 in there from what Im looking at. ....well actually I would need to know how much clearance you would have inside the door. Most definitely i could sink a shallow sub in there easily.

Here is a quick rendering...lol....save the pic because it will be deleted from my photo storage soon.

 

[ndm]

NiAgain....use the 3.5 inches in front of the door and sink the rest of the sub into the door.

 

[ndm]

13TW5v2-4 - Car Audio - Subwoofer Drivers - TW5v2 - JL Audio

Just an example of what could be molded in there.

 

[cybercop]

��$600����

 

[ndm]

��$600����

 

[ndm]

��$600����

http://www.amazon.com/13TW5V2-4-Audio-4-Ohm-Shallow-Subwoofer/dp/B009UYZO0I