Hey everyone. Decided to finally build a custom sub box for my FC. Box is going in the back passenger side corner.

Got the following:
Elemental Designs e3.8 8" sub - 350 Watts - DVC 2ohms each
Elemental Designs nINE.1 amp - 400 Watts at 4 ohms - 900 Watts at 2 ohms - 1200 Watts at 1 ohm
FD 100 Amp alt
Optima red top

Obviously wiring the DVCs in parallel for 4 ohm load, amp might be a little overkill for the one sub, but it leaves me a lot of flexibility in the future if i decide to add another sub, plus i got a hell of a deal on it, but i won't get it until January.

Making a sealed box, all fiberglass, aiming for 0.4ft^3 including displacement of the sub itself. I've worked with fiberglass a little in the past, but this is my first major project with it. All I've done so far is lay down masking tape in the corner. Going to do tin foil and first couple layers of glass tomorrow, would do it tonight but i gotta do some driving and don't want to deal with the fumes. It is rather cold outside, but I figure some extra hardener in the resin and a blow dryer should compensate nicely.

Any comments, questions, tips, etc., are all welcome. I'll update as progress is made, hoping to get some major headway before Christmas. And of course, pics:

Subwoofer:



Masking tape:

 

is thing going to be a ported box or a fully sealed box? are you going for clean bass? or are you going for "slap" factor?
have you looked into port volume and volumetric efficiency?
what amp is this going to be run off of? how many watts RMS are you looking to use?

see what im getting at? you might want to rethink your idea purelly for the reason of what sound are you looking to get out of it.......

Lloyd

 

fully sealed box, looking for clean bass. nINE.1 amp running 400 watts rms at 4 ohms, sub goes 350 rms, so I will be turning the gain down a bit. If that turns out to be too much I'll turn it down some more, if not enough I'll add another sub, the amp can support it.

What would you recommend if I'm looking for some good clean bass? I don't need people 3 blocks away to hear me, I just want my music to sound good. Lots of rock and classic rock.

 

well, the 8" sub is perfect for clean sound if you wire the sub for 10-16 ohms. you only want low resistance for huge lows and "slap" (i cant think of another word)
if i may, i would recomend doing a single bandpass box and having the sub at 10-16 ohms with the high pass filter on.
i take it you listen to rock judging on your conservative setup. i would say a single 8" would be good, i ran 2 10" inch jbl subs and i listen to mostly metal, had to tune the **** out of the amp though, but i also listen to some rap to.
anyways, post pics of your setup, im eager to see what you do with it.

Lloyd

 

really appreciate the advice on everything.
couple things, though... I have never really heard of wiring a single sub with 2 2-0hm coils for 10 - 16 ohms and don't really know how I would do that short of wiring in one, or several, beefy resistors. And even then I'm not sure how my amp would handle that kind of load. Granted, I am not a car audio genius by any rate.
Another issue for me is space. I would like to keep as much hatch space as possible and a sealed fiberglass enclosure that is molded to the far corner will be much better than bandpass box that will need (i think) to be of MDF constructions and twice (?) the needed volume. On top of that I have no idea how to build a bandpass box, and I'm trying to do this all myself.
Pretty much at this point, I have the equipment, and I think I'm going to stick with my original plan of sealed box. If this box turns out to be not exactly what I was hoping for, then I can redo it in the future.

On another not, I laid down my first layer of fiberglass, but this is going to be a slower process than I at first thought, due to weather.

 

ya, try some more MEKP to speed up the vulcanizing process, but dont go crazy.
go to fiberglassforums.com and look on their about all the different ways to make sub boxes and such

Lloyd

 

set up looks good! I just got a huge ported box for my 12 inch and it takes up my whole hatch along with my capacitor and amp

 

exactly what I am trying to avoid :P

thanks for the link to the Fiberglass Forum. Some pretty cool stuff going on there.

 

looking good

 

im on there seldomly, but they have some genious' on that forum. like scary how good they are.
oh, and dont bother running a capacitor if you were thinking about you, you dont have nearly enough power running to use one.

Lloyd

 

Yeah just looking around it's scary. And no worries on the Cap, way ahead of ya

 

I dont even think you read Scrims post before posting all your questions. Almost all of it was right there for you to read unless he edited it and added all that info.

I like your idea Scrims. Good idea to buy a bigger amp than what you need as well to add later if you want to. I would start low on the power to that sub and move up from there. I see no reason to wire to 16OHms on such a simple setup. Wire that to 4Ohms and call it a day. A sealed box with that sub should have clean, tight bass if built to the specs you listed. Good luck and have fun.

 

Greatly appreciate the kind words. Construction has been rather delayed due to illness and now on vacation, but I'll get updates going when I get back :P

 

OK got a question for everyone while I get started again on this project.

How should I go about running wires into the box? I have a terminal cup thing from an old dual-12" sub box sitting in my garage, but I'm not sure about cutting a big hole in the fiberglass for it, and I'm also not sure where I'd put it since there aren't too many flat surfaces on the box...
Maybe I could simply run a couple wires into the half-box I have now and fiberglass over them to complete the box?
Any other ideas?

 

they sell binding posts on parts express here >> http://www.parts-express.com/wizards...AT&srchCat=107 or you could just drill a hole and stick the wires through and silicone them in so its air tight

 

good call on the binding posts. I'll be picking some up.

 

i would just drill a hole hardly big enough to pass the wires, put some quick disconnects on them and call it good. Silicone and then slap some resin inside and out for good measure. Id say this is the simplest and safest way really.

The binding posts are a nice touch though I must admit.

 

ok, so I've mounted the ring and have 3 layers of glass down front and back. My question to you all is how many layers do you think i should have? With this small sub I was thinking 5 or 6, but I'm not sure. Thoughts?

I'll be posting pics of the process once it's all done.

 

For that sub, 5 or 6 is plenty I think.

 

Ok, so the box is as done as it's going to be right now. Have to go back to school across the state tomorrow and I wanted something that works for when my amp comes in a week. I am ashamed to say that this project was more than a little rushed and the end product shows that. I only bondo'd it once and there is only a couple coats of primer on it. I will more than likely go back in the future and either polish up what I have (or disguise it) or do it completely over.

That said, It is very very close to the correct size I wanted (~0.45cu. ft.) and is quite robust. It fits very snugly in its place and I don't think I even need to strap it down with anything. Simply put, the box is a beast, and an ugly one at that.

I'm also trying to keep in mind that this is my very first attempt at something like this.

And pics of course...

using packing peanuts to measure volume:


old t-shirt stretched and resined:


light shining through the first couple layers:


bondo:


ugly-*** primer:

 

installed pics:

 

next time use pieces of fleece blanket instead of the shirt, it will be alot thicker, stretch easier, and turn out nicer.

 

I say start over and take your time. Good first try.

 

Nice Scrims. If anything you can make a cover piece to match your red interior when you have time. It may not be pretty, but it looks to be very solid and correct air space. How does it sound is the most important thing of all?

Also, whatever happened to Mr. wire it at 10-16 ohms? lol.

 

Something will certainly be done to it eventually. I've kicked around the idea of carpeting it, vinyl, more bondo and paint, or just completely redoing it, haven't really decided any way. I do know that it will be staying like this for a while, gotta focus on school right now, senior year of college and all.

I'm still waiting on the amp for this guy, should be here sometime this month. Ordered it during ED's pre-production sale of it. But once it comes I'll most certainly post results, possibly a video.