Trunk upholstery 101

CarMichael Angelo

my rearend will smell so minty fresh,
15 Year Member
Nov 29, 1999
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Birmingham, al
Going hand in hand w/ my last post, the fact that the car is apart for the A/C install just wasn't enough "work" for me it seems.

I no sooner get the evaporator partially mounted, and it becomes painfully obvious that I'm gonna have to do something about hiding all of the mess that will accompany the main unit.
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Just like an "addiction", putting that ugly little somb itch back there, and the fact that it displaced my subwoofer, forced me to consider doing some other things .....:chin

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All of this is 1/4" mdf held in place w/ 1x1" riveted alum angle and hot glue. The covering is red/black trunk mat.

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I still have the filler neck to cover. It's made, but I didn't have time to get it covered by the time I decided to call it quits.

There is sawdust all over everything, so the reason the stuff looks dirty in the pics, is because it is. It's pretty much mocked up, but it all has to come back out to finish the A/C install.

The other problem that presented itself was what to do w/ the subwoofer. I did not want it taking up anymore of my now smaller trunk, so I had to get creative.

I built a small "truck box" type enclosure for mounting behind the front seats. I get one built, and place it behind my seat, and despite the fact that it is as small as I can get it, I still cant get my seat slid back far enough to accommodate my long ass legs ( I actually extended the seat tracks 2" last year)

*sigh* all for the sake of a stinkin' subwoofer:nonono:

So, I give up on having two subs (one behind each seat) and decide to relocate the one I have built behind the passenger seat. It was at this time, that I, (do it twice Mike) decide to actually measure the enclosure I have built to determine how much internal volume the tiny truck box actually displaces. I check my owners manual for the sub, and it says that the ideal internal volume range for a sealed enclosure is between .5, and 1.4 cubic feet. I whip out my ruler, make the required measurements, plug in those figures, and divide them by 1728,..........................................................
.35 cu ft. :mad:
PHUCK ME ALL TO HELL.

So to compensate, I cut the other box down by 1.5"(so it'll fit behind my seat) and seal it completely closed. It's just a box. No woofer. I measure it, and it now displaces .3 cu ft. as well.
We do some simple math, add the two together, and I get .65 cu ft.
Perfecto Amigo.:nice:

All that's left is to tie the two together. So I get some 2.5" PVC and do just that.

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Put that sucker in place, and it looks like I planned it that way.

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Sall good.;)
 
Very nice job boxing out the trunk. Nobody will ever know there is a huge a/c unit back there. Is the 1/4" MDF relatively strong?

That is also a very creative way to get more cubic footage out of a sub box. Does that work acoustically? I don't know audio very well, but does the cubic footage have to equally surround the sub, or does it just need space to move air to? Almost like an expansion tank of sorts (for air), I guess?

Paint that conduit black and you're good to go.

Oh, and paint over the area your grinded away for the those grounds in the last trunk picture. The exposed metal is bothering me :p
 
I haven't listened to it yet.

All I know is that the trapped air in the enclosure is the cushion that dampens it's movement. Not enough cushion, and the woofer bottoms out and "pops". Too much, and the cushion becomes equivalent to a worn out shock. The excess air space allows the woofer to move too much and is slow to return. The bass becomes sloppy, and boomy. It probably isn't gonna be "ideal" by any means, but I'm not trying to bust my ear drums, I just like the additional bottom end the woofer adds. I figured that since it was in the passenger area w/ me it wouldn't have to be as loud as it was before when it was trunk mounted, but after talking to a couple of sound guys, I was surprised to learn that the bass note will be louder outside of the car than inside the car. (some BS about the length of a sub harmonic sound wave taking a certain distance to fully form) blah, blah, blah. :bs: Regardless of whether it's louder outside than it is inside, if it performs w/ out any sound anomalies (pops, or causes some residual weird ass resonance in the other box) I have what I want.

A place to mount a 10" sub that doesn't take up the trunk and still allows my interior to "appear" normal.
 
Oh, man, you should have went with the flannel pattern trunk cloth that was common back in the 50s and 60s! Would have fit the theme of the car, IMO. Either way, what you did there looks great!
 
I'm going to make a guess that the coupled box will have some resonant frequency. Hopefully, it will be so high that the sub woofer will never hit it. It will be very interesting if it does....