How To: Custom Sub Enclosure

[pride4zeal]

How To: Custom Sub Enclosure

I am not responsible for any damage done to your car if you decide to do this project, I am only trying to share what little knowledge I have for the benefit of others, that being said.



I had a lot of people ask me about my sub enclosure and how I built it, unfortunately I didn’t join C3G until after I finished this project so I don’t have all the pictures I wish I would have taken, so please bare with me I will try my best to explain everything. (By the way my project took an entire weekend so give yourself some time, don’t rush it will look like crap). Also you should have your sub, amp, etc. pre wired with plenty of length in the rear before you start this project, if not I will be posting a how to on running wire for amps and subs as well. (This build will eliminate your spare tire, just so you know)

(please read completely before build, know what you’re getting in to)

Ok let get started

Here is a list of tools and equipment I found useful during this project-

-Table saw
-jig saw
-miter saw
-belt sander
-drill (preferably cordless w/ screw setting)
-a good set of drill bits
-a good set of hole saws
-wood plainer
-skill saw
-shop vac
-air compressor
-clean work table (for upholstery, I use a 3x8 costco table)
-wood clamps
- straight edge
-square
-staple gun
-sanding block
-razor knife
-and your set of mechanics tools

Material list

-I used a 6’ x 8’ sheet of ¾” fiber board (not ply wood or press board as these are prone to swell and crack) but depending on your build you may get away with less.
-9’x3.5’ of speaker/ audio carpet
-2” x 2” I used pine cause its what had, I used about 25 feet
-3M spray adhesive #80
-I used my pre existing sub box because I love its sound and did not want to mess it up, but if you decide to build your own that is ok also, more power to you
-screws (1 ¼” and 2 1/2”)
-filler (bondo or spackle will work)
- You will need poster board or card board and masking tape to make your templates

Prep

I started by gutting my trunk, if you plan on insulating your walls with dead skin or similar you will want to do this now. Pull your amp, sub box, stock trunk floor board carpet (I cut mine right at the point it touches the floor board and left that piece mounted in-between the seat back and the trunk), jack and spare and set aside for now. Take this time to clean and vacuum this area, I have seen some weird stuff in these areas.

Take your original floor board and pull off the carpet (don’t worry you will be making a new floor board that has brand new carpet) you will use the board as your template.

Place the original board back in the trunk the way it was. There will be gaps along the edges of the board and the wall of the trunk. Note; you should still have all your trunk plastics installed for this.

Take your poster board and make templates for these areas, but remember you will be carpeting the board so leave some space along the edge. (for the rear right and left side you will end up with sort of a wing, you will want to make these pieces separate when you cut out your board, always try to visualize the install, think will this fit in here when I’m done).

Once you have all of your templates made lay them out and look for mistakes, if none then trace them out on the fiber board, remember it’s always good practice to cut it bigger rather than smaller, you can always trim.

Once your boards are cut out lay them in the trunk and check the size, make sure it fits well because this will be the base for everything.

Once all your boards are cut sand the edges and surface, take time to do it right you don’t want your carpet ripping on sharp edges 2 months down the road.

Place board in trunk, don’t carpet it yet you will be setting wood and sawdust covered material on it.

Take your pre built sub box, I believe mine was 15” x 17” x 17”, and position it to your liking, I liked the look of a vertical facing sub but I’ve done this with horizontal facing subs as well.



Once you have determined the position of your sub box begin to cut out templates that will enclose the box. (this is probably the hardest step in the build, don’t get frustrated with it just take your time)



Once your templates are cut out temporally tape them in place and see if you like the look, if not now is the time to make changes, don’t be afraid to experiment with new ideas.



If you like the look it’s time to trace out the templates on your fiber board, same as the floor board

Continue to fit the pieces around the sub box and message it to a nice fit, again remember the carpet and how am I going to fit this in here.

Once you have gotten every piece done its time to put it together, I found doing this with the sub box upside down is the easiest then you have a nice flat surface to work with.

Once you have the box and the top pieces laid out begin to build your frame or skeleton out of the 2”x2”, and remember this will be the support for your box and enclosure so make it strong. Tip; counter sink every screw if will make the final build simpler.

Once your frame is made test fit it in the trunk and test fit all pieces, if changes need to be made do so now.

If all components fit, begin to assemble the enclosure, constantly check the fit, counter sink every screw.

By now you should have your enclosure built and ready for the final stages.



Start by sanding your box, I started with 60 grit, get everything smooth, some edges may need to be pained down

Now you need to fill any gaps with filler (corners, screws, holes, etc.)

After filler dries sand again

I chose to do a 60 grit sand, 120 grit, and final 240 grit.

Check final fit, and remove floor board from trunk.

Once you have everything sanded and ready, blow off all sawdust and dirt and set prepped pieces aside away from work area, take this time to clean where you are working, you do not want to do upholstery work in a dirty shop, you will hate yourself.

On your clean table lay out your audio carpet upside down and lay your floor board on top upside down as well, now think which side you are going to upholster and make sure it’s the right way.

Cut out the carpet and leave yourself plenty of room I cut 4 to 5 inches away from the board itself, you can always cut off extra.

With the carpet cut and board on top (clear everything off the table but), start with the front of the board, with the underside facing up spray a little adhesive on the edge and wrap carper around and staple, it keep the carpet tight.

With the front in place turn the board over and begin spraying the board and stretching the carpet, start from the front and work your way to the back keeping the carpet tight, note do not spray the carpet itself the glue will go through the carpet and show on the top.

Once the top is glued flip over and begin wrapping the carpet on the edges, a little patience goes a long way here, staple everything down.

Allow floor board to dry and then install in the trunk.

Now repeat upholstery process for enclosure, take your time you want a show piece not something you’re scared to show your friends.

Once enclosure is complete allow to dry and install.

Now you will need to install your box, sub, amp and whatever else you are going to add and wire it up. (I will be posting a how to on this as well)









Congratulations you should now have a custom sub enclosure for your 3G.

If anyone has any questions feel free to pm me.

GOOD LUCK.