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Ford DIY StealthBox for FS Bronco....

15K views 47 replies 18 participants last post by  Sixlitre 
#1 ·
Just got a whole crapload of info off of this site for the 302 to 351W swap I plan in the coming months since my poor ol' 88' 302 is leaking like a #%$@# sieve.... TY all for the great tech readings!

In appreciation I thought I'd share the pics I took of my recent 10" stealth sub install I did, thought some of you might appreciate it for some inspiration....

The full write up is here:

http://www.carsound.com/UBB/ultimatebb.php?ubb=get_topic;f=4;t=006818

















Still designing the grill so that it will fit with the contours of the rear side panel.... The entire amp/sub is completely installed behind the factory panel, the only visible evidence is the grill which I intend to blend with the factory interior. Figure they can't steal what they can't see and better yet, I lost ZERO cargo space!! More pics as it progresses...
 
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#5 ·
Cat's @$$ couchflambeau !

Very nicely executed ! The installer I talked to said the more corner and indents the better, so yours should sound great.

Countryboy

to stay flush with the side vinyl you can't go much deeper than 5 1/2" or you're through the outer rear quarter skin;



Sixlitre
 
#6 ·
The box might be a little on the small side for the JL woofer I used, I'm guessing the box is in the .5-.6 cu ft range, which is slightly smaller than recommended. These days you can get 10's that will do that small, but they tend to be very inefficient.... you have to stick a LOT of power into em to get reasonable output. This is more to fill in the lows that the aftermarket 6 and a half's and the 5x7s just can't manage, definitely not something that you hear down the block. But for what it does, it sounds great.... very accurate.

Sixlitre ... dunno if you cut that fender already but if I were you, I would leave that x'ed portion intact (everything forward of the tack welds) and cut around the double steel. I'm not a mechanic (yet) or an engineer, I'm not sure how much the truck depends on that as structural support.... But I can tell you cutting that double thickness is a big PITA if you're just using an air powered reciprocating saw.... ;)

5 and a half inches sounds right but the higher up the fender you go it tapers off to about 2-3 inches.... which is the nice thing about working with fiberglass, you can make it any shape you want..... definitely the way to go for this application.
 
#7 ·
This is the grill design, but I have to redesign it.... if you look at the bottom left arcs that make up the edge of the grill, it doesn't quite flow with the original lines, so I'll end up recutting/routering it. Might see if the local upholstery shop has grill cloth just a LITTLE closer to the right color too... (I'm picky like that!)



Feel free to post whatever questions you have about the design, or PM me. I'll try to get you set straight if you're going to try this mod and I think I might still have a template or two for the dimensions. Most of my advice is from an audio installers perspective (I was an MECP certed installer before I started working for the gov't). When I do my 5.0 to 5.8L swap in the coming months I'm sure I'll be bugging ya'll for info since underhood mechanical isn't my strong suit!

-B
 
#9 ·
couchflambeau said:
This is the grill design, but I have to redesign it.... if you look at the bottom left arcs that make up the edge of the grill, it doesn't quite flow with the original lines, so I'll end up recutting/routering it. Might see if the local upholstery shop has grill cloth just a LITTLE closer to the right color too... (I'm picky like that!)



Feel free to post whatever questions you have about the design, or PM me. I'll try to get you set straight if you're going to try this mod and I think I might still have a template or two for the dimensions. Most of my advice is from an audio installers perspective (I was an MECP certed installer before I started working for the gov't). When I do my 5.0 to 5.8L swap in the coming months I'm sure I'll be bugging ya'll for info since underhood mechanical isn't my strong suit!

-B

You're way too hard on yourself Couch

I think it looks great IMO. I was gonna do what Sway did, but your cover looks much better as it's way thinner. What thickness and material is it ?

Don't worry about the Xs I was just showing the spotwelds. I ended up, as planned, doing this;



and after a lot of soundproofing and boxing up, then this;



I highly recommend adding the second pair of 8" mid ranges in your stock 5X7 location (in pic). Wish I'd done that first as I would have never bothered with the single 10".

The pair of 8" mid ranges, coupled with the pair of 6 1/2" mid ranges in the doors kick @$$ and IMO negate the need for a 10" sub all together.

Sixlitre
 
#11 ·
rugerp89ipsc said:
damn you guys are really making me wish i had some panels in the bck instead of the plastic black crap I have. That looks seriously sweet.
What's stoppin' ya ?

It's only the 78-79s that can't do this and that's just because you can cut through metal that thick:toothless

they can always make panels and you can always drop by a junkyard and pick yours up.

Sixlitre
 
#12 ·
The main baffle is about 3/4" thick..... I started with a piece of half inch MDF, routered the halfround on the edge, also routered a piece of grill mesh flush into the middle which makes the actual grill. I then had to space it out another 1/4 inch for clearance issues..... but that was just done with a piece of 1/4 inch MDF cut to size and glued/screwed to the orignal baffle.

I'll probably take the cloth off and recut those sides, so I'll get some better pictures of both sides of the grill.
 
#13 ·
couchflambeau said:
The main baffle is about 3/4" thick..... I started with a piece of half inch MDF, routered the halfround on the edge, also routered a piece of grill mesh flush into the middle which makes the actual grill. I then had to space it out another 1/4 inch for clearance issues..... but that was just done with a piece of 1/4 inch MDF cut to size and glued/screwed to the orignal baffle.

I'll probably take the cloth off and recut those sides, so I'll get some better pictures of both sides of the grill.
That'd be great if you could get pics Couchflambeau

From here it looks like it's only 3/8" thick. Very professional looking IMO.

How are you holding them on ? I bough these to use, just like home speakers;



Sixlitre
 
#14 ·
I used some of that "plastic velcro" and it was a bit too strong, ripped it right back off even when it was stapled. So I was either going to go with smaller tabs of regular velcro or maybe order a set of those grill snaps thru parts express. I've used em before on speaker boxes and they're pretty sturdy....
 
#16 ·
what kinda subs are the reversed ones?
what kinda amp u using?

i've got 2 sony xplod 12's in a nonported box w/ a 600 watt xtreme amp


im working my way to 2 memphis audio 12's in a ported box with a uhmm (dont know what its caled, but it loks like a sub, but isnt. it makes the box think its 2x as big as it is = more thump!

and then a 4channel 1000watt amp....
 
#23 ·
Larston said:
You guys that can do this stuff just make me sick. Every time I try something like that it turns out looking like a kindergarten project :banghead

Looks great! :rockon
Thanks dude.... I wouldn't call that behemoth you built a kindergarten project... that thing's insane!

---------------------------------------

As for volume determination.... water is something I wouldn't recommend, MDF has a bad habit of swelling when exposed to water.... I've heard of people using sand or some other non liquid material. Styrofoam packing peanuts, but I can see that as being compressable.....

If you guys are considering a project like this.... I wouldn't get TOO hung up on exact box size though. Sealed enclosures a somewhat forgiving and so long as you get it good and airtight, and make sure the sides are thick enough not to resonate, it should sound fine. Don't forget too, most times you can be +/- 10% on the enclosure size and it still should sound great.

In my case, I know my box is a little on the small size, probably .6 cu ft for a speaker that wants to see something more like .7-.8 cu ft. My output is probably a little lower than optimal, tuning frequency (natural resonance of the box) is a little higher.... but when you're doing something like this, you have to make compromises. When I set out to do this, I wanted to make sure it fit completely behind the factory panel, since I leave this thing at the airport for weeks at a time, don't want to worry about the box getting stolen. Also, my music listening preferences.... since i just wanted to get back those low frequencies I lost when I high passed my front/rear speakers at 80 Hz. That in mind, the slightly undersized box isn't a problem.... and when it was all said and done, it sounds great!

Try it, you might like it!
 
#24 ·
couchflambeau said:
As for volume determination.... water is something I wouldn't recommend, MDF has a bad habit of swelling when exposed to water....
sorry if i was not clear, i meant a purely fiberglass interior to the box. MDF is very absorbant, and it will weaken quickly when exposed to water, which greatly hinders the performance of your box.
 
#25 ·
u just use the interiour dimentions... then calculate the air space..... MDF board is 3/4 thick so take ur outside dimensions and then take 3/4 off all sides then multiply length x width x height and u get the volume... if ur using inches... for every 1728 cubic inches equals one cubic foot. (i build alot of custom boxes for ppl) a square box would take me like an hour to design and make... once u start gettin angles in ther it gets a lil more complicated.... like my box (pictured b4) the back is angled with the seat and the top has an angle to it.. and then each sub has its own chamber in it so thers 3 chambers 1.5 cubic feet per 12 inch sub and 2.5 cubic feet per 15 inch sub... it actualy took me 5 hours of non stop calculations and size changes to get all my chambers correct with the sub displacement and have the right outside dimensions.... then a few hours to cut, assemble, and carpet.
i drew it all out and explained it... (if your interested)



picture link if it doesn't work right http://www.geocities.com/zdemolitioncrew/subexplain.jpg

thers alot of mispelling i'm kinda fallin sleep while doing this. sorry
 
#26 ·
Ogre, I am afraid you slightly missed the point. The volume calculation was for an organically shaped box (ie some more easily accomplished with fiberglass that conforms to the sides of your trunk or car), in which case the general length x height x depth formula no longer works, nor are any mathetical calculations practical since it would take some insane combination of bezier curves and integration to find the volume.

Although I am not saying what you posted is not great information for someone looking for how to calculate geometric box volume.
 
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