b0mbrman: The last sub box is only 1.0 cu. ft?? You sure it's not more than that?

 

Yeah...because when you actually make it, you'd have to use 3/4" all around instead of 1/2" or else you'd lack the structural integrity...

0.84 cu ft is what it looks like doing the math...0.93 if you manage to use 1/2" MDF without the box exploding...

 

I built a fibreglass box for 2 8's. The nice thing about glass is that you can take advantage of all the available volume and you can shape it pretty easily using a mold. Mine is done so that it has a cutout that lets me mount an amp veritcally within the tool well in addition to the subs to save space.

This was my first crack at a fibreglass box, so there are a few things I'd do differently if I ever do another, but overall it wasn't particularly difficult, just time consuming and messy. If you're thinking of going this route, I'd be happy to share any tips I picked up doing mine.

 

j_c_a, I have no idea how to mold fiberglass, it'd be a damn nice intall though If I knew how. It'd be nice with color matching paint. But anyway, doesn't sound a bit different than just using like particle board?

I also have my tool kit taken out as well, so I could probably get away with a slightly larger box. My sub only requires 1 cube. anyway. I'll let you guys know the pricing and setup, and you guys can let me know what you think is the better deal.

Johnny

 

J_c_a, please share some info about working with fiberglass. Time taken, # of layers, etc. Did you go through the whole mold-making process? I read some sites which recommend just laying lots of aluminum foil and fiberglassing right in place.

I'm riding the fence about which way I want to go.

 

My box was my first attempt at any fibreglass work, so any experts out there feel free to chime in ....

Also, vs. a pure MDF box, I think an MDF box would definately be less of a hassle, and cheaper to make. The big advantage w/ fibreglass is that you can get more volume from the available space in the toolwell, and it's better for making non-rectangular recesses if desired. I spent about $70 in fibreglassing materials at West Marine.


I did about 8 layers in all, although it depends alot on your design. Curved fibreglass is very stiff and strong, while straight fibreglass has to be much thicker to be stiff. Some internal bracing also goes a long way towards making it stiffer.

As far as time, yeah it's time-consuming. You really only want to do a couple layers at a time and then let it dry overnight. I didn't sand between layers and didn't have a problem. None of my fibreglass is visible when the box is installed though, so I didn't worry about making it too pretty.

As far as a mold, I used the tirewell/toolspace in the trunk of the car. I built a couple "pockets" into my box for mounting other stuff. I used cardboard to create the neccessary recesses in the box. For a release agent I used duct tape. I tried to use plastic sheeting but had trouble getting it to lay flat enough. I'd be nervous about using foil because one rip would get resin on your carpet. If you go this route, you should pull your box out of the car after the first layer or two while it's still fairly flexable. Also, while I'm thinking about it, the duct tape makes a pretty sticky mess due to the glue when you remove it from the box. I'm thinking that a masking tape of some type might work better. Also, COVER EVERY SURFACE OF THE CAR THAT"S EVENT REMOTELY CLOSE TO YOUR WORKING AREA TO PREVENT DRIPPAGE.

A couple of things I picked up:

1) Buy a bunch of cheap ($.50) brushes. You can buy a bunch of these for the cost of a decent quantity of acetone and it's a lot easier just to toss 'em than bother cleaning them.

2) Don't get those surgical gloves they sell for working w/ paint and fglass. They'll rip apart the first time you touch any resin that's a little tacky. I went through an entire package before I discovered that dishwashing gloves work much better.

3) Cut you glass cloth into smallish strips, approx. 2" x 8". Originally I thought it would be more efficient to use larger pieces, but quickly discovered that big pieces of cloth make for lots of creases and air pockets.

4) Cut more cloth for each layer than you think you'll need. It's a real PITA to stop in the middle of a layer and cut more cloth.

I did a lot of research on the internet. Some of the stuff I found was helpful, some not, and some contradictory. Here are a few links :

http://www.ofsoundmind.com/osm/install/glassbox.html
http://www.carstereo.com/help/fbglass.cfm
http://www.eatel.net/~amptech/elecdisc/caraudio.htm

If you decide to go this route, I'd be happy to answer and questions that I can, although I'd be the first to admit that I'm a relative newbie re: car audio stuff.

 

I installed Focal 165K2's this past weekend. I used Lucid's speaker adapter kit. I ended up using all the nuts to provide enough space for the speaker to clear the window. It's a pretty close fit.

I tried setting the tweeter crossover to the -2dB setting at first but ended up using -4dB. I'm running the Alpine 9815 for the headunit and the Alpine T420 as the amp.

I'm also running a 12" Rockford Fosgate Punch DVC in the trunk that I had in a previous car. It sounds great but I'm not sure I can sacrifice all the room. It's just in a box sitting on top of the tools right now.

 

David at Mobile Acoustic makes custom 10 and 12 plexie box's for the S2K, but I can't post anything more than that due to S2KI regulations for there sponsors. I'll PM you with info.