Building a sub box for my Forester...

[CTENG in KS]

I was gonna wait on this till I was done, but I am bored so here is what I have been working on lately.
The Foresters music situation was deteriorating...the cd player wouldn't play disks anymore, the speakers were buzzing in the front tiny bit. So I decided it was time to upgrade.  I wanted some nice stuff, not terribly expensive, and I wanted to keep it from looking gaudy and stupid.  I want the car to remain looking stockish so thievers wouldn't be too tempted.

Few mouse click and stuff started showing up at my door.  I love boxes of stuff.



I started with a Nakamichi head unit...I love how PLAIN it is:



I used some Eclipse 6.5's in the door to replace the mid bass drivers from the original component set.  The stock tweeters are still in there, functioning fine so I figured I would let them be for now.
Alpine Type S 4 inch coax's for the rear doors.  Nothing special, sound great at a great price.

Then came the fun part of the project.

[Huhwhye]

That's cool man.  That is a nice looking head unit, I like simple too.  Some have too much going on, and I don't care about graphics and such. Just good sound at a good price.  I'll have to check it out, what did it cost?  What is the model #?

I have the stock HU in my 4runner and it sucks, so do the stock speakers.  I've only had the rig since december but I can't stand it much longer.  Problem is I sunk all my cash into gears/lockers/suspension/tires.  So I will have to live with it for a while longer.  I kept my amps and my sub from my last truck but I have nothing else to hook it up to.

[CTENG in KS]

I wanted to run a small sub in the back, but I do not want to lose much cargo space, gotta fit all my steel in there for building the 4Runner.  I decided to mold a box to the area behind the dr side wheel well.  I have never built a box this way before so I figured it would be a fun project.

Here is the area I want it to go:



I decide I am going to do a glass backing, so I am using felt to make the initial mold.  I considered fleece cause it is easier to impregnate with resin, but it is too floppy to get it to stay in position along a wall.  Anyways...I plasticed it all up and went to town getting the felt in place.





Now this is where I made my first mistake.  I am wanting to get the mold for the back done in glass, then use MDF for the front and top panels.  I did fine getting resin onto the felt to make the mold of the back section, but I should have considered more carefully where the mating surfaces with the wood were going to be.  I didn't and left them to come out all bump and and uneven.  Stupid AJ.  This has added several afternoons to the project as the back could no longer just be screwed into the MDF. 

[CTENG in KS]

That's cool man.  That is a nice looking head unit, I like simple too.  Some have too much going on, and I don't care about graphics and such. Just good sound at a good price.  I'll have to check it out, what did it cost?  What is the model #?

I have the stock HU in my 4runner and it sucks, so do the stock speakers.  I've only had the rig since december but I can't stand it much longer.  Problem is I sunk all my cash into gears/lockers/suspension/tires.  So I will have to live with it for a while longer.  I kept my amps and my sub from my last truck but I have nothing else to hook it up to.

I can no longer find it for sale anywhere.  Need to check the website, maybe they have a new model?

[CTENG in KS]

The mold came out of the car clean, no problems.



Then section by section I started glassing the inside of the mold.  I used a tan felt so I don't have to remove the felt...it just becomes the backing of the box.



Then cut a base outta 3/4 inch MDF and attached it to the bottom.  Test fit looked good.

[CTENG in KS]

Then is was all about trimming her up and getting the top and front panels cut.  Since I was to short sighted to make the mold smooth where it attaches to the MDF, I had to cut the panels to "pretty close" then glass the whole deal together.  Here is how it sits curing in the garage.  This week I should be able to cut the speaker hole, mock up the amp, and mount the wire terminal.  After that it will get a vinyl cover as close to the interior of the car as I can find.

[CTENG in KS]

It almost fits perfect except for a little spot where it interferes with the gate.  Arrrr....

[Trunkz]

are you putting vent holes in there?

[CTENG in KS]

No, I don't like ported boxes.

I need to figure out how to secure it to the car.

[Huhwhye]

No, I don't like ported boxes.

I need to figure out how to secure it to the car.

I'm no help there.  I always have my box flopping around in the back.

[CTENG in KS]

More I look at it, the more I don't like it anyway.  I might need to try again...or something. 

[Trunkz]

but the ports equalize the pressure inside and outside the box so the speaker doesnt pop from compressing the air

[Huhwhye]

Some prefer the sound of a sealed box.  I'm one of them.

[DTB]

Some prefer the sound of a sealed box.  I'm one of them.

not me! I prefer ported bandpass, especially in a SUV or wagon.....much BOOMIER (is that a word? )

[CTENG in KS]

I think I will build a second box this afternoon, all MDF.  See if I like that better.  I can pick this one up later and mod it if I want, but I don't feel like working on it anymore.  Poopy.

[Duffil]

be sure you

[CTENG in KS]

OK, only took 1.5 hours to throw this together.  This is much easier with just MDF.  Decided to go with a smaller box in a different position.  This one looks like it will be much easier to mount as well.  It is a tad over 0.70 cubes, the amp will mount to the back.  There is enough room due to the slant of the back seat for air to pass by the amp.

[jimbo74]

how are you going to anchor it? or are you jsut going to let it sit there?

also, doesnt someone make a box for that? i know most suvs have premade boxes that pop into those little cubbyhole areas

[CTENG in KS]

nope, beside...more fun to build myself.  I have two factory tie downs all steel on either side of the box.  Gonna use hidden adjustable straps to cinch it down.

[CTENG in KS]

I got it all put together and sanded down and sealed.  It is glued, screwed, and siliconed to a lovely air tightness.

[CTENG in KS]

The sides are grooved like that so I can make nice seams with the vinyl covering...but there is where I ran into problems.  I started with some HD contact cement...and it destroyed the vinyl...



Then I went on to trying 3M Super 77 adhesive...seems to work well...



Until it started delaminating from the backing and ruined itself...

[CTENG in KS]

I tore all the vinyl off and sanded down the backing that was left on the box.  Then it was time to try something different, and more expensive.

Suede!




Then got to the first seam.  Took some time to figure it out, but it is working.







Then on to the ends.  VERY time consuming.  This is where I ended for today.

[CTENG in KS]

And she's all done...
Tomorrow should be a lovely day for an install!

[NorCalToy]

nice. looks like a fun project. ive been thinking of doing something like that for the back of my truck.

[CTENG in KS]

Fun would have been knowing what  was doing from the start.  It took me a month to get to this point on a simple box.  I am VERY happy with the way this second one turned out, but I have covered it nearly 3 times.  The first two were disasters.

The suede turns out to be very easy to work with, but it is painstaking.

[CTENG in KS]

It is all done.
The Nak head unit is simple and unassuming.



And the box fits in perfect, matches the color pretty well too.





I used straps to the stock tie downs plus industrial strength velcro on the bottom.  It doesn't move at all.

[NorCalToy]

nice job wat size sub is it?

[CTENG in KS]

It is an Elemental Designs 9Kv...it measures out to a large 8 inch.

I am VERY happy with the sub...it put out quite a bit more bass than I was expecting.  Surprised me when I first turned it on.

[THK Matt]

8's are surprisingly punchy.


here's what ive noticed.
12's rumble
10's hit hard and are cleaner sounding
8's are punchy!