[larrikinstreak]

Custom Sub

Having been frustrated at trying to purchase subwoofer pod for my hatch. I decided to
make one myself, out of fibreglass. The internet is a great help but here's a simple way
to make your own subwoofer pods, borrowing from many;

I chose the left rear as there is ample room for a ~35L enclosure without eating too much
of the hatch space, which was an important consideration for me. I also chose to design
for a 10" driver as this results in a smaller enclosure and I prefer a punchy/crisper bass.

You will need;

Around 5L of fibreglass resin, plus catalyst to suit.
3 sq m of 420gm chop-strand mat.
Half a dozen cheap paint brushes.
Stretchy material for the front.
Plenty of masking tape !
MDF for the base and spkr ring (I used 9mm)
Speaker Carpet (JayCar)

Step 1

Make a MDF base for the speaker pod, thankfully the hatch floor is flat so it makes
a great place to start. I cut mine with a jigsaw out of 9mm mdf, for a small pod this
is thick enough. Use 50mm masking tape and tape/mask up the whole area, and
then some, the tinfoil is good for protecting nearby stuff If you look carefully
you can see I drew the rough outline on the tape...



Here's a wider view of the layout.



Before you do any glassing, move outside ! this stuff stinks And get a warm
day so the fibreglass goes off , 15C+...



Apply a layer of resin onto the tape with a paintbrush and then stick pieces of
the chop-strand mat to the resin, this helps to keep it from falling off. You only need
one layer of mat at this stage. Work resin into the matt until it is well penetrated
and stick it to the top of the MDF base. Build it up more in the corners for strength.
Then let this go off and cure for at least 2 hrs, then you can remove it...



Step 2

At this point you can pop it out of the car. Remove the masking tape asap as it tends
to leave some of its glue in the car carpet. Below is the pod with just one layer of
fibreglass done...



After it was out of the car I applied 3 more layers to build up the thickness. Its about
6-7mm thick at this point. I trimmed and test fitted it again....nice



Step 3

The speaker support ring is made form 9mm MDF and this one was cut by hand, which
is tricky, if you have a router you can cut a neater one. The pic below has the support
ring in place with only one mounting. I added another 2 once I was happy with the position
of the ring. The mounts a glassed into pod back, base and screwed to the ring, three mounts
about 120 degrees apart.



Step 4

Sorry no pic of this...

Stretch flexible cloth material across the front of the pod and attach to the rear with masking tape
or staples. Apply only resin to this cloth and leave it to go hard. Dont worry about the excess cloth at
this stage, you trim it off later. I applied 8 layers of resin to the inside and outside of the stretchy
cloth over period of a week, it ends up smooth and strong. Many others apply mat or chop-strand
but mine ended up very strong and solid without it. Cut the excess stretchy cloth so that it goes
around the face and behind by say, 30mm, then resin it down to fix it.

I gave the whole pod a quick sand and then stuck speaker carpet to it...
(with contact adhesive) Its an easy job that gives a good result.



Step 5

Trim and tidy it up....



Step 6

The inside is lined with speaker dampening material and at the rear are external terminals,
the sunken type, all sealed. I have an older Kicker F10A installed at present but I have
another driver coming to replace it.

[Gruggy]

Looks as neat as a factory install. Fantastic work

great DIY Geoff

[confuzion]

that is so good!!! cheers for that looks tops

[larrikinstreak]

Here's what it looks like installed



And...



It sounds great with just HU drive, Pioneer 8950BT, but will be driven with another amp soon


Well I hope this helps anyone thinking of having a go Its not hard and cost be about
$200...

[Max_Power]

That looks pro mate. Good work.

You really should have used chop strand matting on the front as well though as that's what provides the structural strength. The resin is just the "glue". How solid is it though? Does it flex at all when you push down on it? Have you stood on it? I've made one of these for the corner of my boot and used no less than 10 layers of 225gm matting to make sure the thing was solid as.

[aus301]

Have to agree with using the mat on the front, I tried it this way on a previous car and had flex, so found that I had to apply a few layers of matting to the front to get it strong.

But great write up, well done. Would be getting hard to find a +15 deg day in Canberra at the moment to get the resin to go off.

[larrikinstreak]

Max_Power, on Jun 2 2007, 10:58 PM, said:

You really should have used chop strand matting on the front as well though as that's what provides the structural strength. The resin is just the "glue". How solid is it though? Does it flex at all when you push down on it?

I did agonise over whether I should use chop-strand on the front or not, as everyone else
does it, but a mate who worked in the business said it wasnt as necessary as ppl think. The
front doesnt flex and you cant deflect it a mm by hand. Remember its a small
sub, that makes a big difference inthis instance. I dropped the thing (by accident) and it bounced

Aus301: Acoustically a small amount of flex wont hurt much if you have sound deadening
on the same surface, I have that polyester material inside and carpet on the ouside. We
played around with running it with no dampening, before the crapet, sounded ok ??? wtf.
With the lining and carpet it lost any 'ring' it may have had.

[Asymmetry]

Fantastic job!

If you keep the copy of the sub box, and had it reproduced a few times somehow, could made a little cash

Look like a pro job, well done

[Sime]

Great job! Looks like a pro job as the others have already mentioned.

When you said it cost $200, is that just to build it, or does that include the driver as well? Where did you get the fibreglass materials from?

Also, when you removed the glassed box from inside the car, did it just pull away from the tape?

Can I ask how you secured the box from moving around in the boot?

[larrikinstreak]

Sime, on Jun 3 2007, 05:59 PM, said:

Great job! Looks like a pro job as the others have already mentioned.

Thanks

When you said it cost $200, is that just to build it, or does that include the driver as well?

Ok, just the encloure. I have an old Kicker F10a driver in it at the moment which is not ideal
for this pod but I was keen to test it out. The volume of this sealed pod is just right for many
10" drivers, it gives me more choice.

Where did you get the fibreglass materials from?

Nearly all of the fibreglass materials, resin, mat, catalyst were from Bunnings but I did have some
things in the shed already from previous (non spkr) projects, like rollers and mixing containers, disposable
gloves, MDF etc, I estimated what they might have cost.

Also, when you removed the glassed box from inside the car, did it just pull away from the tape?

I pulled the tape (and layer1 of fibreglass) away from the car first, slowly working it from the
edges inwards (took about 10mins). Once the whole lot was out of the car the masking tape peeled
away from the fibreglass without much trouble. I used a trick knowing that the resin, close
up against the tape, would not have fully cured yet and so it peels off easy. It doenst matter
if you cant remove it cleanly, its out of sight.

Can I ask how you secured the box from moving around in the boot?

Its such a snug fit (because of the shape where it is) it hardly needs anything. However, I have
velcro strips for the base and the rear/side just in case. I havent put them on yet. I thought about
using one of the side tie points too. If I have problems then at least I have a few ideas to try