Following on from Cevans request I thought I would do a thread rather than clogging up the original, so here is how I built a sub box for the footwell in a 914.


Remove interior and totally deaden the whole footwell. Masking tape overlapped and then covered in release wax.







Use fibreglass mat and resin to form the back of the enclosure, push it hard into the firewall - you want to get a tight fit..



Remove the fibreglass from the car once cured, it should remove easily as the release wax has formed a great barrier. Cut a baffle for the subwoofer you are using (I do a double baffle, so the trim material can be folded over the edge, rather than the sub sitting on top.) Put the Sub IN the baffle and play around with angles - obviously it needs to not hit the firewall, or the enclosure you will be building - the angle of mine faces up under the dash to avoid getting 'kicked'

Once you have finalized the angle, use some hot glue to fix a couple of dowels to the ring and the fibreglass backing to secure the angle and hold the baffle in place. Remove the subwoofer. Get some material, fleece or an old Tshirt and staple this to the speaker ring, stretch it tight to the fibreglass to form a cone in which the subwoofer can sit..










Soak this in resin and wait for it to go off. Now the front of my sub box follows the same line as the original passenger foam pad - this was made by cutting a piece of MDF to fit the front panel - the internal volume of the box extends behind this, I managed to get about 0.7 cubic feet internally..

Fibreglass over the whole thing again and again to build up the layers (and strength)

Then cover in carpet - I used the AP carpet set and asked for extra to be sent over so I could cover this box..

Good luck, have fun!!!!

Very cool!!!!

Very tight!

nice job
i was gonna put mine in the front trunk, but yours makes me wonder to change my idea

The front trunk installation won't work at all. It's totally sealed from the cabin and is separated further by the front firewall, the fuel tank and then the forward firewall. You hear nothing but rattles. I tried it once for fun and it stank!

Thanks! Very nice work. I like the fact that you can bring the car back to original fairly easily.

Really nice! What kind of volume do you think you ended up for the enclosure? What did you do on the left side?

I've been wanting to do something like this for 15 years. What I had envisioned was to make the enclosure like the foam filler, but bring the "foot board" part out 4"-6" to add volume, and make it more of a folded horn, like the old Peavey SP1's. and then you totally hide the driver. I was thinking a dual voice coil single sub with the biggest magnet you could get.

WAY COOL !!! thanks for the thread.

Now that is my kind of hot rodder!

Good Job.

Fabbing your own parts is THE essence of what I think is cool.

Thanks everyone for your kind comments, glad you like the install..



Agreed - the front trunk is very sonically detached from the cabin, so not good. the only other option I would maybe do in the future is move the fual tank to the wheel well and rebuild the bulkhead with a sub mounted IB - (I have an Image dynamics IDW15 to do this next )




I tried lots of locations for the sub and the sub I use has a huge magnet CDT QES 820.. The problem with moving the footboard forward is that the footwell becomes very small very quickly I moved the footboard forward maybe an inch, two maximum, any bigger than that and the passengers knees were in their chest

Mounting the sub at the angle I have increases the volume available, I got just over 0.65 cubic feet which is ideal for the sub used.

When you ask what I did on the left side, what do you mean exactly??

When you ask what I did on the left side, what do you mean exactly??
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In the first and third pictures you have the drivers side footwell taped up also like you are planning some fiberglassing like you did for the enclosure.

Ah right I see.... Whilst doing the sub box I took a mould of both the passenger and drivers footwells, so If I need to build another enclosure I have the back premade

I used the speaker pods from AP in the end to try and keep it looking as factory as possible. The AP pods have the speaker facing straight out, which didn't sound good with my speakers so I adjusted them with more fibreglass work and vinyl to angle up, so the opposite driver is on-axis....

Again great work! The good thing about the stock speaker location is that it does give good stereo imaging.

My plan was to put mids in the stock location, just like you've done, put surface mount tweeters in the corners of the dash reflecting off the windshield, and then the sub in a custom box. Never did it though. Had the first kid, and then the second, and....what did we do with our time before kids????

That is very clean. Those would sell like hotcakes! I thought about doing something with the foam as well, but the volume just didn't seem like it would be there (with any integrity left). I looked around for a box that would fit (width wise) where the foam is/was. I found that the Sony Explod actually fits pretty well. It is only about 6" and change thick and 17" wide, and just tall enough that it fits right in. Yes, there is a loss of some leg room...but I mostly drive alone. And when I do have a passenger, its usually a hot girl - who loves music!

Those are 5 1/4" MB Quartz hiding under the eclipse covers on the center console and Alpine 6 1/2" in the A&P pods. I am running a 4 channel Alpine for the speakers and a bridged 2 channel Fosgate for the sub (located in front trunk). Sounds pretty good...

http://www.bestbuy.com/site/olspage.jsp?sk...d=1166235821990