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Discussion Starter #1
Guys, I am going to be completely redoing the install in my car (96 Accord sedan) and I need some advice on my sub enclosure. While I love my current setup, I hate listening to my wife ***** and moan about not having room for luggage, groceries, dead bodies, you know, the things people usually put in the trunk of their car.

I've decided to compromise with her and so I'm going to be scaling things down with a pair of shallow 12" subs. My plan is to build a downfiring enclosure that spans the width of the floor between the shock towers. Gives me about 32" or so of width. The enclosure will probably be around 6" deep - or tall, depending on how you look at it I suppose - not including the height off the floor.

I'm looking at a downfiring enclosure for a couple reasons. First, I'll have the enclosure itself as usable floor space with the ability to fold the rear seat down for more room if needed. Second, The subs will be protected from rogue objects moving about in the trunk. Aside from my own reasoning, I've done some research and from what I gather, downfiring provides increased output and less cancellation similar to loading against the back of the trunk.

Where I'm unsure of, and could require some experimenting, is how to go about building the gap below the enclosure, if that makes any sense. It seems logical to me that building a 3-sided platform of sorts would create something similar to a slot vent. Or perhaps it doesn't matter and I can just use simple blocks in each corner. The box will be secured to the existing MDF floor I already have installed so I can pretty much do whatever I need to.

Thoughts?
 

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I would go with the simple blocks in the corner or maybe just building a 2 sided platform. Make sure you leave as much space for them to breathe as possible. I normally try to give around 3-1/2"-4" clearance. I've had very good results from firing down. Clean, nice little boost in sound. I think you'll be happy with the results!
 

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I am Godzilla
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6" seems awfully shallow when you consider breathing room and the thickness of enclosure material (assuming MDF) and the body of the shallow driver. I've had a single 10" Cadence in a sealed enclosure, with not enough power or "breathing room" and it suffered as a result, but wasn't awful.

Good luck,
The Hammer
 

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Build the enclosure as normal, whatever your design idea is.... Account for 3/4" on each side/end of the enclosure extra for two "legs". Cut these to that same dimensions as the enclosure, on all sides except for the bottom/base/baffle side. This side will extend out to whatever height you decide you want the enclosure to sit above.
 

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Discussion Starter #5
6" seems awfully shallow when you consider breathing room and the thickness of enclosure material (assuming MDF) and the body of the shallow driver. I've had a single 10" Cadence in a sealed enclosure, with not enough power or "breathing room" and it suffered as a result, but wasn't awful.

Good luck,
The Hammer
The drivers are just over 3" deep. They're not very deep at all.
 

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6" seems awfully shallow when you consider breathing room and the thickness of enclosure material (assuming MDF) and the body of the shallow driver. I've had a single 10" Cadence in a sealed enclosure, with not enough power or "breathing room" and it suffered as a result, but wasn't awful.

Good luck,
The Hammer
5 posts in over 6 years...where have you been:confused:

Come join the party:laugh:
 

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I just threw this together to nest under the package shelf of my sisters '05 Trailblazer. Old school JL 15W6 gettin' pushed around by an Alpine MRP-M500. I looked for info about calculating the correct amount of buffer, but found very little, so I guesstimated. Most if not all of the down firing Stealth boxes I've seen have under 2 inches of clearance, so I made the chamber depth as shallow as I could and ended up with 2" of breathing room....we shall see if it will be suffice. I only had 11" of available height and originally planned to fire a single 10" back twords the hatch, but knew she would enevitably over-drive it or run something thru it, so this was the next option to keep space at a maximum, protect the sub, and keep the package shelf intact. Was able to squeeze it in, to cover only one seat side leaving the fold down pass thru unobstructed.
 

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I have one in my Tundra as shown in the pics and it works beautifully. The highest point is 6" from the floor, as that is all the space I have under the rear seat. More room would probably help but there isn't any audible chuffing etc.

I have this in my wife's Yukon and it also does the trick. It is obviously bigger then you want but the three sided enclosure with a slot opening is the same in theory. INVERTED WEDGE DESIGN
 

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In a Perfect world, you want half of the diameter of the woofer for clearance.
Most of the time it is much less.
ya gotta do what ya gotta do.
 

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Discussion Starter #13
In a Perfect world, you want half of the diameter of the woofer for clearance.
Most of the time it is much less.
ya gotta do what ya gotta do.
I'm thinking about 3" should work for a pair of 12" drivers.

Looking at some boxes I see the subs are angled slightly. Does this help with anything in particular or is it going to affect the sound at all?
 

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Angling the subs slightly, may help direct the sound, but I would think it would be a marginal gain, if any. If you try this make sure there is sufficiant room inside the box to account for the magnet to swing closer to the wall and the top of the box.
Another thing to consider is the position of the box in relation to the rear of the seat. If you close off the back side (making three walls for it to stand on) and push it right against the seat, be sure the sound can still escape somewhere. You don't want to muffle them. Also, depending on how the rear seat meets the floor, what type of material the rear of the seat is made of, and weither or not you have leather seats, you can greatly inhibit the transfer function, by mounting the subs this way. If you leave the back open, I suggest covering it with a piece of expanded steel wrapped in grill cloth. The last thing you need are any unwanted objects migrating under the subs, and lodging between them and the floor, causing carnage.
Also a "leg" in the middle will help disperse the weight, and keep it rigid, when stacking something on top of it.
Best of luck!
 
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