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Oh, Herro!
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Discussion Starter #1 (Edited)
...my new stereo install :D . Since 1CLNB14 called my old setup "ghetto" (which it was...) and the box was absolutely massive and took up half my trunk (1.25 cubic feet for a 10"... what was I thinking?), I decided to re-do it about a week ago, with four goals in mind.

1. The box had to put audio quality first. I designed parameters for the box dimensions and built the rest of the system around the sub box.
2. The box had to look relatively factory. Going with my goal with the Sentra to be my interpretation of what the stock Sentra should have been, the box had to blend in well with the factory decor. This meant no crazy fiberglass, no weird colors, and no Plexiglas windows, etc.
3. The box had to take up a minimum of space. My car is a daily driver and needs its trunk. Floor-mounted subs and amps are a no-no.
4. The box had to leave the spare tire in place and fully accessible without removing the box. Since my car sees around 200+ miles of freeway driving a week, the spare tire was a must.

With these goals in mind, I designed the box. I settled on an interior volume of .72 cubic feet, including the displacement of the sub. Unfortunately, this was a little small for the sub (recommended volume is .80 cubic feet, not a huge difference), so I decided to use the 1.5 lbs of Polyfil from my old box in the new one. I decided on .75" MDF from the local hardware store, which cost me $23.35 for a 4x8 sheet, plenty for what I was doing. Unfortunately, my first bit of cutting didn't turn out so well. The angle markings on the saw were not very accurate, and my beautiful 45-degree miter joints turned out to be 50-degree, enough that all the panels had to be scrapped, along with the idea of using miter joints. I recut the panels and attached the new ones using a thick layer of Elmer's white glue and 2"x8 self-tapping flat-head screws, countersunk into the wood. Once all six panels were in place, I layered on an 1/8"-thick layer of Bondo on the inside to seal the box. This ultra-messy stuff has a horrid smell, and I highly recommend good ventilation when working with it. I'm sure I'm about 500 brain-cells short now.
The amp mount was a little trickier. I wanted to be able to see the amp and I wanted plenty of air to get to the amp, so hiding it was out of the question. However, going with the stock look, I didn't want to be able to see the mounting screws or any wires. Mounting it through a cutout from the back seemed like an interesting option. I cut a panel that extended off the side of the box and cut a hole for the amp to mount through. I also chiseled away the back side of this panel to provide room for the wires. The amp was mounted through this panel so the heatsink faced the same direction as the sub and all the wires, controls, and mounting screws were completely hidden behind the panel.
To make the box and amp mount look a little more factory, I make a panel to mount on the top that fit the contour of the wheelwell and all the junk in the trunk of the car. Using a piece of aluminum foil and a piece of cardboard, I made a template and cut it out, filing it down to fit. This was mounted to the top of the box with 1.5"x8 screws, countersunk of course.
The floor of the trunk also had to be redone, since the old floor was a cheap piece of chipboard that was sagging from two years of various heavy guitar junk in the back. Using the same MDF, I cut out a new three-piece trunk floor, one piece for the back of the trunk, one for the right side under the box, and one for over the spare tire. These panels were connected to each other using short wooden dowels that are drilled into one panel, and a cut-out to fit the dowel in the corresponding panel. This keeps the trunk floor totally flush and is strong enough to support upwards of 100lbs in the trunk. Any more than that will require removal of the floor, which is amazingly easy thanks to this dowel-system.
Keeping with the stock look, I chose a dark grey fleece as the material for the trunk floor. This fleece is very stretchy, making it easy to carpet, very soft, and is a beautiful charcoal grey color. It's also surprisingly strong and very difficult to cut with an Exacto knife :) . Using Elmer's Spray Adhesive, I attached to to the faces and exposed sides of all the panels. The bottom of each panel is uncarpeted since you can't see it and to save material. I also chose to carpet the sides of the trunk to match. This material proved very easy to work with and made beautifuly smooth creases on every panel.
The sub was installed using 1.5"x8 screws and the box was filled with 1.5lbs of Polyfil to help make up a little for the small volume. Wiring is done through a sealed terminal cup.
The sub is a Panasonic EAK-WG25. It's a 10" sub designed for 120w RMS and 450w peak, with a sensitivity of 90dB/W/m and a 44.9 oz magnet. The amplifier is a Kenwood KAC-428S that puts out 100w RMS and 200w peak in bridged mode. Wiring is using Monster Cable 4-gauge power and ground wire and Monster Cable C-5M RCAs. The sub recieves power through 16-gauge standard speaker wire.
Some final adjustments still have to be made to certain panels to make the fleece hold a little better, but this is what the finished product looks like. What do you think?



 

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samo,

nice install!!!!!:D i was thinking of doing the same thing for my 200sx only on both sides with four tens and an amp rack in the middle. man it looks really good though id be showing that baby off!!! hows it sound? just wondering, i have an audio compition to go to on the 24th of aug. and want my install looking as sweet as yours. thats if i have your permission to copy your design a little?;)
 

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Oh, Herro!
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2,337 Posts
Discussion Starter #3
It sounds great. The SPL is decreased a little from what it used do be, probably from the smaller box. However, it difference is hardly noticible, and it still pounds plenty hard for my tastes. I have noticed that the transient response is much much better and the sub is audible on lower volumes. The audio quality is fantastic considering the components I have used are not top quality.

Feel free to copy my design if you choose - it's a copy of someone else's anyway :) . Good luck in your audio competition.
 

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thanks i may need it! I need allot of work done yet. my trunk right now looks like a rats nest of speakers amps and wire!!! it sounds really good, from what i've been told, but i dont want people checking out my system and say what a mess. although out here in this flat place they call the great plains i havent heard too many people that can out perform my sound quality but there is some pretty big sponsers supporting this so i dont know how far people are going to be coming here for it. man back home on the east side i wouldnt even be thinking of competing!!!:)
 

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Oh, Herro!
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Discussion Starter #5
By the way, I think you're going to have a difficult time mounting four 10"s on the side like that. The box would have to stick out easily another 10" from where mine is. You could make two fit, one on either side, really easily (build mirror-image boxes, basically), but I'm doubting that four would fit. It's worth a shot, though. Be sure to post pics when you're done!
 

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Oh, Herro!
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Discussion Starter #7
Thanks man. It took a lot of planning and a ton of hard work out in the 90 degree sun. I'm glad it's finally finished.
 

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Registered
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I have to say I'm pretty impressed, I've got two Rockford Fosgate HE2 12" subs and a RF 700S which ain't that small and I've been toying with ways to improve apperance because I have a pre-fab box in there right now, I hate it. It isn't nearly as loud as it can be and it takes up everything in the trunk, everything so yea. Judging from what you've done I might be able to put one twelve on each side, but I might fiberglass enclosures angled toward the back seat so they aren't directed directly toward each other and posiblly have the amp in the middle underneath a hidden panel, minus one spare tire.
 

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Oh, Herro!
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2,337 Posts
Discussion Starter #12
Thanks for the compliments guys. Feel free to steal my idea - I stole it from someone else and he probably stole it, and on down the line :) . So far it's my favorite mod to the car and the one I'm most proud of.
 

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pay your rent!
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samo said:
By the way, I think you're going to have a difficult time mounting four 10"s on the side like that. The box would have to stick out easily another 10" from where mine is. You could make two fit, one on either side, really easily (build mirror-image boxes, basically), but I'm doubting that four would fit. It's worth a shot, though. Be sure to post pics when you're done!
Will do Samo! A friend of mine is really good with carpentry work and he wants to help. he said it would be hard too:( . but has a plan to put them on angles so he can make the proper box size. I'll lose allot more trunk space this way but from what he's saying it'll look pretty good.
 

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Oh, Herro!
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2,337 Posts
Discussion Starter #14
If you put each sub at about a 30-degree angle firing toward the rear of the car, you should be able to make them fit, but that leaves you with an oddly-sized trunk floor. You could then mount the sub amp in the floor itself under a cover if you wish. It would really help if your subs were designed for small enclosures, but I'm sure you can make it work.
 

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i was thinking the two twards the front would be at a angle and the two at the rear would face each other. my speakers recommended box size is .75 cu feet so i think i can work this out. there made for a smaller enclosure.
 

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Oh, Herro!
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Discussion Starter #17
Wald - thanks for the compliment!

Landlord - .75 cubic feet will work great for a box like this. My sub was designed for .80 and I put it in .72 with a lot of Polyfil. I'm not so sure I would have two subs facing each other exactly - I don't know much about this, but it sounds like you might run into some cancellation problems on certain frequencies. I would talk to somebody who knows a bit more about the physics before you design it.

EDIT: Grammar.
 

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pay your rent!
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i talked to my local dealer to make sure and i was right when the speakers face each other the air compresses and when the bass drops it drops! (kind of like a band pass) im still working on this box, im in the design fase right now and so far so good. im having trouble with the cubic feet this is stuff i havent done sense i was in high school!!:( because of the way the 200sx's trunk is shaped this is proving difficult. my 91 would have been much easier! man i miss that car.
 

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Tuner/Mechanic
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266 Posts
nice work samo! anyway, do you know about how much of the 4x8 sheet of mdf you used? i was wondering how much the whole thing, including new trunk floor, weighed. estimate? oh yeah, dig the wheels!:D
 

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Oh, Herro!
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2,337 Posts
Discussion Starter #20
Thanks for the compliment. I probably used about 90% of the sheet including making the trunk floor. However, four panels went to waste in the process because I didn't cut a real great angle for the miter joints :rolleyes: . I can't imagine the setup weighs less than 75lbs inc. the sub and amp. It's not light by any means. However, considering how extremely strong it is and how awesome it sounds, it's a reasonable trade-off. And the SE-R wheels tear it up, I love 'em!
 
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