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View Full Version : Schematics for 15'' Top Firing, Rear Ported Enclosure



Rzaa
02-04-2007, 11:11 PM
This enclosure is being designed for a Adire Audio Brahma 15dr4 MkIV being powered by a Hifonics 1606d amp. I mostly listen to rap/hip hop, but theres a little bit of everything on my ipod. I'm planning to install it in the back of my '03 Tralblazer, so space isn't much of an issue.

The only thing I've decided on so far is that I want it to be top-firing and rear ported; other than that I'm pretty much in the dark as far as design goes. Right now I'm leaning towards somewhere around 30-35hz @ 3-4 cubic feet.

Here are the specs on the driver:
Fs 24hz
Qes 0.59
Qms 8.2
Qts .056
Vas 152 liters
Re 2 x 3.3 Ohms
Le 2 x 0.34 mH
BL 19.0 N/A
Xmax 28.5mm
Sd 740 cm^2
SPL 87.4 dB
Pmax 600W


If anyone can help me design/knows of a schematic that will suit my needs I will much appreciate a point in the right direction. Any help at all is appreciated, thanks beforehand.

wcarson8911
02-04-2007, 11:41 PM
i dont know the driver displacement on that sub or your max width and height, so i used .2, try some of these, see if they work...

1 (http://www.subwoofertools.com/forum/ported-box.asp?Ew=37&Eh=15.5&Dia=9&Xmax=28.5&Vd=.2&NumW=1&Vb=3.5&Fb=34&Qts=&Vas=&Fs=&CE=0)

2 (http://www.subwoofertools.com/forum/ported-box.asp?Ew=40&Eh=16.5&Dia=9&Xmax=28.5&Vd=.2&NumW=1&Vb=3.5&Fb=34&Qts=&Vas=&Fs=&CE=0)

kicker06
02-04-2007, 11:44 PM
Here are my designs for a 15" Fi BL. 4cu ft @ 32hz w/ 66" of port each.

Model #1

http://img407.imageshack.us/img407/3709/bl15as5.jpg

Model #2

http://img149.imageshack.us/img149/5238/final2uf9.jpg

wcarson8911
02-05-2007, 01:03 AM
Here are my designs for a 15" Fi BL. 4cu ft @ 32hz w/ 66" of port each.

Model #1

http://img407.imageshack.us/img407/3709/bl15as5.jpg

Model #2

http://img149.imageshack.us/img149/5238/final2uf9.jpg

what is the widthxdepthxheight on that box???

Rzaa
02-05-2007, 03:24 PM
When making top-firing, rear ported box, would it be a good/bad idea to double the baffle?

JohnBlayz142
02-05-2007, 03:59 PM
It will never hurt to double the baffle. When you're dealing with high wattage systems like a Brahma + ~1500 watts, I'd double it without thinking.

Inner bracing is very important also.

Rzaa
02-06-2007, 09:11 PM
Here are my designs for a 15" Fi BL. 4cu ft @ 32hz w/ 66" of port each.

Model #1

http://img407.imageshack.us/img407/3709/bl15as5.jpg

Model #2

http://img149.imageshack.us/img149/5238/final2uf9.jpg

Do you happen to have the dimensions for the 2nd model?

Also, when double baffling, do you use 2 identical size pieces of MDF, or do you make one that is 3/4'' smaller all the way around (centered on the top board), so that the inner piece would fit securely into the box (effectively doubling the surface area for gluing) this is assuming taking in to account the inner piece for volume calculations.....

Any help is appreciated, thanks beforehand.

kicker06
02-06-2007, 10:14 PM
Do 2 same size if you have the height, so you have to add 3/4" to your total height.

Box 27wx28dx14h

Port 25.5w x 2.5 h x 22.5 d

For model #2, and those are ext dims.

Rzaa
02-06-2007, 10:17 PM
Yea, height isn't an issue at all, I'm not trying to keep it under a cargo cover or anything. On the 2nd design, does the placement of the sub matter at all? Aesthetically I would like to place it in the center, but would having it closer to the edges help support it?

mazdakid
02-06-2007, 10:24 PM
try to keep the sub away from the port opening inside the box

kicker06
02-06-2007, 11:04 PM
try to keep the sub away from the port opening inside the box

You want it near the front, because the port opens at the back.

dvrmstrng
02-06-2007, 11:06 PM
when you say near the front do you mean near the port or side opposite the port.

Rzaa
02-06-2007, 11:10 PM
I'd assume close to the port as illustrated by the picture.

dvrmstrng
02-06-2007, 11:22 PM
is there any disadvantage to mounting the sub directly in the middle...

Rzaa
02-08-2007, 01:03 AM
is there any disadvantage to mounting the sub directly in the middle...

I have no clue, but if I had to guess I would have to guess it had something to do with the port and airflow....

Rzaa
02-12-2007, 04:31 PM
I've decided that I want to go top firing, rear-ported, 4.0 cubes @ 32hz. Max dimensions are 40"x30"x40". I didn't like the way subwoofertools was designing the port, so if anyone can help, it would be much appreciated.

kicker06
02-12-2007, 04:57 PM
so you want sub back, port up?

I don't think that way is successful, unless your firing up through a rear deck into the car, in a trunk car.

What car again?

I can do a sketchup design for you.

Also, is that WidthxDepthxHeight?

Rzaa
02-12-2007, 07:13 PM
Sorry for being unclear, but I want sub up, port back. The box is being installed in the back of my '03 Trailblazer. I went out and took exact measurements, and my max dimensions are 45''x37''x20.75'' (width x depth x height). If its at all possible, try to keep the height right at or around 20.75" so that the top of the box is flush with the top of my rear seats. I really appreciate all the help, let me know if you need to know anything else.

kicker06
02-12-2007, 08:18 PM
Im doing it now.

Also, in the SUV's (some) of my friends, port and sub back was louder than sub up, port back. But it is a different design then the plain port back, sub back so it's really up to you.

Ill do the sub up, port back, but I can switch it easy if you want.

kicker06
02-12-2007, 08:42 PM
Heres the size I came up with:

Width x Height x Depth

24.5" x 20.75" x 22.5"

Comes out to 4cu ft @ 32hz w/ 63sq" of port.

The port is 3.25" wide.

Good?

kicker06
02-12-2007, 08:54 PM
Ok my sketchup is completly messed up.

I do not know whats going on.

I gotta figure it out.

Rzaa
02-13-2007, 12:22 AM
Yea man, that sounds perfect to me. I really appreciate the help. If you can get the sketch up that would be great, but if not, don't worry about it.

Rzaa
02-13-2007, 12:15 PM
I was messing around with skechup and I got:
http://www.filepub.com/public/5011/porthelp.jpg

If anyone could double check those dimensions, I would greatly appreciate it.

I have no clue what dimensions the green/red/blue parts should be. I knew you said the port is 3.5" wide with 63 in^3, but I did some searching and only found a thread that further confused me.

I'm planning to use a double baffle, so would I just add another layer of MDF to the top? If so this would give me:

http://www.filepub.com/public/5009/boxfinal.jpg

jdawg
02-13-2007, 12:55 PM
I've decided that I want to go top firing, rear-ported, 4.0 cubes @ 32hz. Max dimensions are 40"x30"x40". I didn't like the way subwoofertools was designing the port, so if anyone can help, it would be much appreciated.

play with the xmax setting, it controls the port width

Rzaa
02-15-2007, 02:57 PM
I was messing around with skechup and I got:
http://www.filepub.com/public/5011/porthelp.jpg

If anyone could double check those dimensions, I would greatly appreciate it.

I have no clue what dimensions the green/red/blue parts should be. I knew you said the port is 3.5" wide with 63 in^3, but I did some searching and only found a thread that further confused me.

I'm planning to use a double baffle, so would I just add another layer of MDF to the top? If so this would give me:

http://www.filepub.com/public/5009/boxfinal.jpg

Can anyone check those dimensions?