Fiberglass Sub-box Walkthrough

[Imrac]

To those that have made custom fits, how did you all secure them to the car? Mine kinda just sits there unless I make a hard right, then it will move around.

[ean611]

Home Depot sells high grade Velcro

 

one of the sides will stick to the carpet in the trunk

 

I use several strips. The boxes are so stuck in there, that they have passed safety checks at SCCA.

[executor485]

Even the Industrial Strength velcro at Walmart is fine, it might even be the same stuff.

Keeps it locked in place no matter how spirited your driving may be.

[OutbackXT05]

Great walkthrough I cant wait to get started on doin this in about a month or so. I do so many things with cars/electronics with walkthroughs I dont know what I'd do without them. I think id probably just die in frustration at most things

[OutbackXT05]

I do have one more question just looking over the write up here. I know you did 3 layers of the glass and your looking to run a jl W3 good sq woofer. But what if i was looking to run a DC audio lvl 4 10 (1000 watts rms) would 3 layers be enough or should I go more just to be safe. Ive never played with fiberglass all my boxes have been made of single or double layer mdf board. Thanks for the help if anyone can answer this question.

[executor485]

Its somewhat a matter of preference. I have read that the way you should be happy with a box is the "elephant test". Literally make the box so that you can have an elephant stand on it. At least thats what JL recommends.

With 3 layers of fiberglass, i have no issues or worries about strength personally. The strength of the box was able to withstand a wreck (wasnt direct crushing to the box, but it took a dang hard hit). If your really worried about strength you could add a few more layers, or even go as far as using felt instead of the fiberglass cloth on the inner layer(s). The worst/only place that sound escapes on a properly done box is through the small hole at the back where you run the wires through, and/or the sub mounting hole. (depending on how you seal that area and run the carpet because the carpet isnt quite air proof worthy. lol)

I havent run a sub like that before, but again, if you're concerned just add another layer and you should be just fine. When you actually start making this, you will see exactly what I'm talking about as far as strength goes. It's a very tough box, even with 3 layers. You might also want to talk to a custom audio shop that makes fiberglass boxes and see how many layers they put on their boxes. I "think" the ones I've seen run a single layer of thick felt. So you could make a shell of fiberglass cloth and an inner layer of thick felt.

[OutbackXT05]

Alrighty thanks for the great info and promt response. I do the elephant test with my woofer boxes (I jump around on them since they are usually 4-13 cubic ft) I make I just have never messed with fiberglass so if its as strong as you say then it'll be no problem. And ya if you use liquid nails like you said earlier youll never have problems with leaks. Ive built at least 30+ boxes with it and for $1.50 a tube it does wonders on sealing EVERYTHING. Just load that stuff on and your good to go.

[1astrokeit]

i was curious if there is a bass difference with mounting subs in the trunk verses mounting under the seat, which i was planning on doing so i hear the bass more and travels less throughout the car.

[executor485]

i was curious if there is a bass difference with mounting subs in the trunk verses mounting under the seat, which i was planning on doing so i hear the bass more and travels less throughout the car.

The argument of under the seat and in the trunk is really invalid in the case of the Legacy. Reason being is the size of the box. You cannot fit a 10" sub with a proper box under the passenger or driver seat. So the bass will not sound or feel as good as a properly made box in the trunk. Sure you have to go through the back seat, but... it sounds just fine. The other thing that can be done is to remove the sub cover in the deck lid. Works well for me, even though I didnt really have issues before I did that either dual 10's FTW. hehe

[1astrokeit]

so these fiberglass boxes will be fine for some thump?

[executor485]

so these fiberglass boxes will be fine for some thump?

 

I'll put it to ya this way... If you can find a 10" sub that fits in these boxes and can blow apart a properly made box, you need to take a picture and show us... and I might buy the sub from ya lol

 

But yes, these boxes are great for that extra thump. They're as good as an MDF box, just that they dont take up half your trunk to do it.

[limbota]

man this looks great. i gotta do this

[1astrokeit]

for those who have dont the floating ring box. after you fiber glassed it and all did you remove the pieces of wood holding the ring in plce ir did you leave it in?

[executor485]

From what I have seen, they use something like hot glue to hold the wooden dowels to the ring. Then when everything is dry, they remove the dowels. Its easy to remove them because its only hot glue, so its firm enough to hold the ring, yet easy enough to remove after.

 

So the simple answer is yes, do remove the pieces of wood. If you dont remove them, they would need to be extremely secure, otherwise they could come loose and damage the speaker.

[limbota]

for the floating ring one. when you stretch the fleece over it. how does the ring stick to the fleece after its all set and done

[executor485]

for the floating ring one. when you stretch the fleece over it. how does the ring stick to the fleece after its all set and done

 

The ring should be held in by the resin and fiberglassholding to it. and when the sub is put in and drilled to it, the sub, through the fiberglass, will hold the ring in place.

no need to worry bout that part. the bigger challenge is actually getting the ring held there before the fleece and resin is set.

[limbota]

oh i understand now

[Noeladams]

Just curious how much it cost to build one of these?

[1astrokeit]

is it possible to install a 12 inch sub? i thought i had 10'' sub but thats not the case. i didnt make the floating ring style. i was thinking of puting and external ring ontop of the mdf to bring it out so i can fit the 12inch sub until i get my 10 inch. any thoughts?

[executor485]

is it possible to install a 12 inch sub? i thought i had 10'' sub but thats not the case. i didnt make the floating ring style. i was thinking of puting and external ring ontop of the mdf to bring it out so i can fit the 12inch sub until i get my 10 inch. any thoughts?

 

I've made 12" enclosures before, they're a VERY tight fit for space if you dont use the floating ring. It all depends on how much you fit the MDF into the fiberglass enclosure and leaving space for the 12". As for just putting a ring on top, you may be able to, but it depends on the basket for the sub. Some subs have a HUGE basket that requires you to have a very large hole cut out (think JL w3 and up series). While other subs have a very tiny basket, so you can just put the ring on there and the sub will fit just fine because the basket isnt 11 some inches wide as well.