# Another quick fiberglass project...sub box



## chuyler1 (Apr 10, 2006)

Well the wife is driving the P5 now and she wanted the spare tire back in. So I pulled the elaborate system and installed some of the gear from her old car. A PPI 5440 5-channel amp and an Image Dynamics IDQ 10" subwoofer. The amp runs DLS Iridium components up front active 30w each (tweets and midbass, no midrange this time) and sends 200w to the subwoofer. Source unit is a Clarion DRX9575 with DPH7500z processor mounted above the amp. Optical signal between head and processor 

The enclosure I built might be a little small for a 10" but I'm guessing it is a little over 0.5 cuft. I didn't bother measure it...I just wanted something small that wouldn't take up useable space in the trunk and would add a little low end to the front stage.

Step 1 was to build the base out of 1/2" MDF. I would have used 3/4" but I had a piece of 1/2 and didn't want to waste it.










Step 2, I added a few layers of double-sided sticky tape to the bottom. This represents the thickness of the carpet flooring in the car. If you skip this step, your box may not fit in with the carpet in place.










Step 3, Mask off the entire piece with painters masking tape.










Step 4, fiberglass! Make sure you build it up so that it is at least 1/4" thick all around, 3/8"-1/2" preferred. You can use cloth glass to start but you need the fiberglass matte to add thickness and stiffness. I precut the matte into 4x4" squares and then mixed about 8 fl oz at a time. Grab cheap plastic painters cups with measure markings on the side so you can accurately measure resin/hardener. Put the hardener in first so it mixes as you poor the resin. If you put it in last, it will stick to your brush as you mix and you won't get a good mix...trust me on that one. That is a priceless tip.










Step 5, After the resin cures pull out your mold and remove as much painters tape as possible (I can never get it all off).


















Step 6, Using marker, mark where you want to remove the glass around the edges...I always go at least 1" beyond where I am going to cut. I use a jig saw to cut the excess fiberglass off.










Step 7, Mount your baffle (sorry I didn't photograph building the baffle...it is just a ring a little wider than the subwoofer with a routed edge for stapling fleece to.










At this point in my project my digi cam stopped working. It just took black photos. Yay! But anyway.

Step 8, stretch fleece across the front of the box. Use hot glue to secure it in place around the outside...stretch it is tight as it will go, any loose sections will sag and wrinkle once you fiberglass. Use a staple gun to secure it around the baffle ring.

Step 9, add lots of fiberglass to the fleece but be very careful around the edges...any extra around the edges will have to be sanded/grinded off. Also be careful around the baffle. I designed my baffle with a 1/4" routed edge and made sure no fiberglass made it onto face of the baffle. That way I could just sand it smooth and not have to worry about a jagged mounting face for the subwoofer.

Step 10, add several layers of fiberglass matte on top of the fleece until it is at least 1/4-1/2" thick on the flat areas. Rounded portions are usually stiffer and don't need as much thickness.

Step 11, Sand off the edges with 40-60 grit and an orbital sander...or use a dremel and grinder bit. Sand smooth the face using 40-60 grit and an orbital sander...good luck if you don't have an electric sander.

Step 12, cover with carpet. That's right, if you are using carpet you don't even have to clean up the crappiness of the fiberglass face. It hides everything. If you want to paint or vinyl you've got lots more bondo and sanding to do.

And, now that you read all that, I'll grace you with some crappy camera phone pics I took last night...



















It sounds pretty good. I did some initial low-volume tuning for my wife and found a crossover point of 50Hz was best at low levels while 80Hz was better for my listening levels. Below 30Hz it runs out of steam due to the small enclosure size but it is tight and there are not rattles thus far.

Total build time was about...hmm. I don't know maybe 8-12 hours including cure time. It could have been done in one very long day. I spent 4 hours on a saturday, another 3-4 on a sunday (getting the baffle to stay in place was a pain since I only had liquid nails...I'll need something stronger next time), and then another 2 hours the next weekend to sand a little and apply the carpet.

Total cost was about $75-100.


----------



## chuyler1 (Apr 10, 2006)

Tough crowd to please I guess.


----------



## shinjohn (Feb 8, 2006)

Chin up dude!
Props for another great job!!!! It (almost) makes me want to go off and fiberglass something. 
Keep up the good work!


----------



## Weightless (May 5, 2005)

Very nice work indeed. 

Clean and tight, just like I like 'em!!!


----------



## chuyler1 (Apr 10, 2006)

shinjohn said:


> It (almost) makes me want to go off and fiberglass something.


Me too, aside from the smell. Now I get to start on my new Mazdaspeed6. The agreement was that my wife gets the Protege5 (its a step up from her old corolla and she is using it to learn stick-shift) and I get the new car...BUUUT I had to remove the old system and put back in the spare. So I mounted the 5-ch to the seat and whipped up this box for her so she'd still have a trunk.

Be on the look-out for a few more projects from my workshop: tweeter pods, door pods, and an amp rack.


----------



## agentk98 (Oct 31, 2006)

Man I wish I had a router! 
Nice Job there!  I think i'll go with carpet in my trunk too if i choose to go that route.


----------



## BoomHz (Apr 20, 2007)

I likes. Been thinkin of postin my last glass.............uh......


----------



## BoomHz (Apr 20, 2007)

Oh yeah................your spoiling your wife with that headunit. I really miss mine


----------



## chuyler1 (Apr 10, 2006)

agentk98 said:


> Man I wish I had a router!


Router is key for all car audio projects. It just saves so many headaches in the long run. Granted I have yet to cut a mounting hole large enough. I am always paranoid about going too large and as a result I have to shave off 1/8" at a time with the router until it is the exact size.



> I think i'll go with carpet in my trunk too if i choose to go that route.


For DIY and something that will sit in your trunk out of sight...it is the best option. See the photo below, that is how smooth the front face was when I covered it with carpet. There was no smooth transition between the baffle and resin...it was kind of jagged and should have been filled with bondo. But the carpet hides all! Even when you run your hands over it you really won't notice the flaws.


----------



## strong*I*bumpin (Oct 3, 2005)

Nice & clean,good work dude


----------



## niceguy (Mar 12, 2006)

Very nice and professional looking.....I'm still torn between a 3.5 Max (6spd) and waiting around for a used MS3 or 6....not sure if the Mazda's have enough interior room (from what I remember test driving when they first came out)...

Jeremy


----------



## chuyler1 (Apr 10, 2006)

The 3 is a little small up front. The 6 is in-line with most mid-sized sedans including the Audi A4 and BMW 3-series. I don't know how it compares to the Maxima but I'll venture to guess the Maxima is a little bigger. You can get a used 06 MS6 for about 18-22K right now. You won't find many but if you keep your eye out and don't mind driving a distance to get one you might get a killer deal. Don't go by KBB. It is way off due to the 5K incentives Mazda was offering only a few months ago. You can get an 07 MS6 brand new for 25-29K so don't be fooled by people trying to recoup their loss after paying sticker price.


----------



## jaopuneis (Jun 4, 2009)

congratulations


----------



## ihartred (Jun 1, 2009)

that is the best 1st post you could come up 
with? on a 2 yr old thread.


----------



## B_Rich (Mar 29, 2009)

lmao....


----------

