Spare Tire Enclosure....

[coldrealms]

I have decided to replace my 2 MM12's with a custom enclosure for 2 MM124's inside my spare tire well. My question is is it better SQ wise to mold the bottom of the well with fiberglass then secure a MDF top or cut all the bits to have a MDF "drop in" sealed box?

Just decided I needed to use my trunk someday and the 2 MM12's kinda prevented that...

Thanks for the advice

[exalted512]

id do whatever is cheaper or easier...either way, as long as the box has .88ft^3 per chamber(youre planning on having 2 chambers right?) then either way...itll be good
-Cody

[coldrealms]

Yea I am planning on seperate sealed compartments for each sub :)
After about 6 hours of research on-line I have decided that with SQ being important to me that I will do a 'glass MDF hybrid enclosure with layers of glass then some thinner MDF as reinforcement (both for strength due to long flat sections and for sonic stability) then more 'glass on that. Im fairly lucky in that my tire well is huge 26" x 26" x 8.5"
I will be taking pictures of the install incase anyone wants to see the work in progress on this project.

[exalted512]

you plan on putting the mdf on the inside right?
-Cody

[coldrealms]

Just got back from Home Depot, the way I ended up going for cost sake was like this. In layers from the bottom of the semi rectangular tire well.

1. Damplifir
2. 2 layers of 'glass
3. Hardboard sheets as reinforcement tot he long straight runs of 'glass
4. 1 3/4" MDF dividing peice
5. 2-5 layers of 'glass to fill up the odd shapped places where the wood can't reinforce and over the hardboard. Also used to make sure the "tub" shape is sealed and very strong.
6. A layer of spectrum liquid dampiner
7. filler if nessesary after final build interior volume is determined (odd shapes suck)
8. a 3/4" MDF top sheet to cover the whole base of the trunk. glassed to the "tub" to ensure 100% air tightness.
9. spare MDF peices to build a riser all around the new trunk floor about 3" high.
10. The final peice of MDF to form the floor of the trunk with 2 rectangular shaped windows 1 for the speakers and 1 for the amp rack.
11. 1/4" high impact acrylic sheets for the windows bolted on with the momo type allen head screws.
12. Havent decided if I want paint or carpet....leaning more twords carpet cause after all this work i think I will be too tired to go further then carpet hehehe.


I will have pics very soon as work progresses. Any and all advice, suggestions, flames, or prases would be helpfull... for now, im going downstairs to measure, remeasure and cut the wood bits

Cold-Realms

[exalted512]

sounds like a plan to me...measure twice, cut once
-Cody

[AustinKP]

Sounds like you pretty much have it figured out. Upload pics soon :)

[coldrealms]

Well things in theory don't always work out the way you plan. Here is the progress thus far and some words of advice.(for those who care and are thinking about doing this type of thing for the first time.)

1) Pictures are coming but only of the tail end of the project as the cam I was going to borrow was out of town when I started this.

2) Contrary to many tutorials out there plastic drop cloth is NOT the right material to use between your car and your 'glass. It moves and buckles (even with lots of tape) and makes a very uneven surface which leads to alot of cursing trying to get the 'glass to not bubble. Use all tape or something hard like aluminum foil with tape.

3) The whole idea of 'glass - wood reinforcment - 'glass was fundamentally flawed as the wood would only create huge bubbles in the overall project and weaken the structure in a sealed speaker environment. The right way would have been to lay the aluminum foil down, then the wood. use lots of wood glue or hot glue to hold the wood together then 'glass over that. After enough layers on top then you can 'glass 1-2 layers over the bottom just to keep it from going anywhere. As it is I had to abandon the wood reinforcement (yes cody I was still able to use the 3/4" MDF center divide ;) ) and just do lots of 'glass. Had to buy 4 extra packs of fiberglass mat before i felt safe enough.


4) When adding layers avoid large single sheets of 'glass, when some tutorials mention in passing that you should cut or rip the 'glass into strips they fail to tell you why. If you try to use large single sheets you get bubbles that you just cant freaking get rid of!!

With the above issues and problems I currently have a rather thick/ bubble filled uneven fiberglass shell that is just finally tonight becoming strong enough to make me feel safe enough to drop my speakers into.

But on the bright side it does fit perfect in the spare tire well. It is strong as all hell, and the right inner dimentions. Also the MDF top piece is turning out well and should cover the ugly 'glass job i did. I think during all this I learned enough to make my door pods for the eventual dual mm6 midbass drivers and single tweeter per door when I get the cash for that.

Thats about all for tonight. I will be attaching the 'glass "tub" to the MDF top in the morning and leaving it in the sun to dry all day, then when I feel it's fully dry (that night or in the morning) I will drop my subs into it and run them on light duty with my old amp to test my monsterous creation. Then if all goes well when i get my wireing from knukoncepts on monday I will hook up my new MTX 1501D Amp and see if it can handle that much pressure. :D

[coldrealms]

A few pictures of the mess in progress.

The trunk in question:

[coldrealms]

The fiberglass tub , upside down being attached to the MDF topper. Pics of the unfinished top will be up tonight while I pressure test. BTW Great stuff foam sealer is a godsend for a new 'glasser making a sealed box.

[coldrealms]

Well, the project is nearing total failure status as neither chamber is sealed right, at this point I cannot pull it apart to see where the problem is. I have 1 hope for salvaging this project and that is in the morning I am going to take my remaining resin and mix it up in small batches and pour it directly into each chamber and "roll" it around so that it coats ever square MM of the inside, including most of the wood (the joint is where I fear the leaks are at) and let it harden and continue to do this on both sides until I am out of resin then let it dry. Hopefully this will coat whatever holes there are..otherwise I will have to scrap the whole thing.

Wish me luck all.

[coldrealms]

Good news, it *appers* that the coating the inside with resin will have the desired effect on sealing the box. I have to wait for an hour or so for it to dry 100% before I actually hook up the speaker for a live test. Once the liquid damplifier comes in it should be 100% YAY

[LittleCar_w/12s]

Sweet job on that. Glad you could salvage it :)
-Jerry

[coldrealms]

Thanks, sadly the cam i was using broke so I won't have pics of it finished, but for now my next project is to try to fit 2 mm6's in each door (well 2 midbass drivers and 1 tweeter) hehe. Saturn doors are pretty small... wish me luck

[LittleCar_w/12s]

From what I've seen of saturn doors, there's room inside, it's just getting it around the interior trim that sucks, but good luck on it.
-Jerry