100% fiberglass box versus MDF or Pine box..

['96_Talon_TSi]

As i've stated several times before, but havent gotten started on the enclosure itself, ive been making over the hatch section of mt car, and will be making a custom enclosure for some subs. I'm having some difficulty figuring out how i want to form the box, whether i should make it 100% fiberglass, or if i should make the box out of MDF, and just layer it with fleece/glass in order to increase the stiffness.

I'm curious about the sound of the full fiberglass box compared to the wooden box. Which would sound better for 2x 10" subs, sealed of course.

If using 100% fiberglass i would make a mold of the backside so it fits right in there perfectly, then just stretch some cloth over the front, followed by 5-7 layers of glass... think this way would be better. Or i should go for the wooden MDF board, cut and shaped to the dimension, slid into place, and then covered in fleece for a first layer, followed by 3-4 layers of glass on top of that?

Opions, Pro's and Con's of each way to make it.... help me out guys.




BTW..It's going to be mounted behing the rear seat, between the strut towers, and the subs willbe facing into the rear. Either construction method used to build it, i will mold the box into the plastioc hatch peices for a seamless transition.

 

[VOTBLINDUB]

I wouldnt say that a sealed enclosure is better than a ported. Its how you want it to sound. I most definitely would go ported, which is what i have now. I had a sealed and a vented box metered in my car and i got 2.4 Db more out of the ported box. You might say: "whats only 2 and a half decbells?" It's a good amount actually, especially at levels over 140Db. Im pretty much in the same class as you with the two tens, i have a single twelve. if you modify yours we'll be in different classes, im keeping a box in the trunk, that can be removed and whatnot. Also make sure you get the proper volume for your subs first then worry about shape and appearance and the rest of that stuff, its the most important part, you dont want it sounding like poop if youre off. You want to use 1/2 inch MDF for a eclosure. Wood resonates sound really nice, why do you think all those musical instruments are wood?:laugh: Anyways. If you want to use fiberglass you can. At least make all the walls and maybe the floor out of MDF and make the top all fiberglass, and put in MDF rings to screw the speakers into. Make it really thik, so when there is vibrations its not rattling or cracking. It might take a while to build up a nicefat layer, but if u gotta use fiberglass, go ahead. As far as facing the subs, there are two ways to go about it. You can make it show and just point them in all weird directions or flip them upside down so the magnets stick out. You can also point them properly to get the best maximum sound out of your setup. If it doesnt say "rear firing design" or something along those lines, you dont really have to point them backwards. Its really up to you if you want to. I have mine pointed straight up so it bounces the sound off the rear window and it goes forward towards the front seats. If you want i can send you some photos of my setup. I hope this helps you out some, if ya got some specific questions IM me or write me a PM. Good luck

 

[redturbo66]

does anyone have a problem with the 3rd brake light hitting the back window. Any suggestions on how to fix it?

 

[jepherz]

First of all, the way you want it to sound is affected by the choice of your subs. If your subs are engineered for a sealed box, use sealed. If they are engineered for open air, don't put them in a box. Simple as that. Yes, wood resonates, but they also make wood instruments out of other composites too. The box can be a lot lighter, but you really want to use as much MDF in the construction as possible because it will be a lot cheaper and easier/faster to build. Also, nothing beats the nice, flowing curves that you can easily mold with fiberglass. In my opinion, at least a fiberglass face of a box is necessary to make it look stellar. Top that with automotive paint and CC and there is no better setup. (Keep in mind, this is just MY opinion. Let's not start another argument thread.)

 

[devlish]

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when building my enclosure, i used MDF for the front/back, but the top is obviously fiberglassed (minus MDF trim rings for mounting the subs too) and the bottom is molded into the spare wheel well, the sides are glassed as well.

Check out my webpage, i have a decent write-up (how-to) that i documented while doing my enclosure. it may help out somewhat, unless you already know about fiberglassing.

as for sound, go with what is reccommended for your subs. Ported boxes are the most efficient, and most versitale. not to mention usually slightly louder than sealed. but it depends on your music tastes too. if you listen to rock or classic or jazz, i'd say go sealed. if you like a mixture, rock/hip-hop/etc, go ported. (this all depends on your subs though of course)

also, i always use a spray-on sound deadoner for the entire inside of my boxes, to seal it up properly, even on ported boxes. (spray cans of truck bedliner work awesome and are cheap - $5.99 @ Walmart)

any questions, feel free to ask!
~Kurt

 

['96_Talon_TSi]

I think I'll probably do the bottom/sides/back, and the top in MDF. Then do fleece, and a few layers of glass on the front and to cover the wood that shows...

Which brings me to the next question. For the first player on top of the fleece, should i use mat, or jump straight to woven cloth? I was thinking a layer or two of mat, then a few more layers of woven.

 

[devlish]

if the top board (the MDF) is to remain flat, then definetely don't bother to glass over it. just prime it and paint it. that way it is already flat and smooth. a few coats of primer and a little sanding will completely take away the look of wood, you won't even know. otherwise you risk bubbles in your fiberglass layer, and need lots of sanding. (a little filler over the screw holes or around the edges where needed, but don't waste time with resin/matting)

this will not work however, if you plan to add shape & curves to the top layer. but i couldn't tell from your last post

 

['96_Talon_TSi]

Originally posted by devlish
if the top board (the MDF) is to remain flat, then definetely don't bother to glass over it. just prime it and paint it. that way it is already flat and smooth. a few coats of primer and a little sanding will completely take away the look of wood, you won't even know. otherwise you risk bubbles in your fiberglass layer, and need lots of sanding. (a little filler over the screw holes or around the edges where needed, but don't waste time with resin/matting)

this will not work however, if you plan to add shape & curves to the top layer. but i couldn't tell from your last post

I dont plan on making any curves in the top. I was going to set it flush with the top of the rear seats, so i guess i'll do that instead.


For the hatch cover, i was gonna give that a glass'd look also. Just spread some filler on that and sand away, or think there is a better way?





Its a damn shame its still freezing cold here (got about 2" of snow last night), or else i would probably be a little further on this project and have some pics for you guys. No use showing a gutted car, we all know what those look like.

 

[devlish]

Originally posted by '96_Talon_TSi

For the hatch cover, i was gonna give that a glass'd look also. Just spread some filler on that and sand away, or think there is a better way?

is that going to be flat as well? or have curves?

 

['96_Talon_TSi]

Originally posted by devlish
is that going to be flat as well? or have curves?

God, im the king of ambiguity in these posts..

Stock shape, maybe i'll fill in a couple of the little divots towards the part where it clips in (if you look at the one leo made you will be able to know what ones im talking about).

I figure i could put some cardboard or some lightweight wood in those divots to fill em up if i decide to.

 

[devlish]

i made a nice flat board by tracing the stock one. then i cut out holes directly above where the subs would be so the sound will travel through. then carpet it and you're done! ( i suggest putting some kind of mesh/wire over those holes before you carpet it or the carpet will sag)

~Kurt