Schematics for 15'' Top Firing, Rear Ported Enclosure

[Rzaa 10+ year member]

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.

Click to read more...

 

[wcarson8911 10+ year member]

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

2

 

[kicker06 10+ year member]

Here are my designs for a 15" Fi BL. 4cu ft @ 32hz w/ 66" of port each.

Model #1

Model #2

 

[wcarson8911 10+ year member]

Here are my designs for a 15" Fi BL. 4cu ft @ 32hz w/ 66" of port each.
Model #1

Model #2

what is the widthxdepthxheight on that box???

 

[Rzaa 10+ year member]

When making top-firing, rear ported box, would it be a good/bad idea to double the baffle?

 

[JohnBlayz142 10+ year member]

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 10+ year member]

Here are my designs for a 15" Fi BL. 4cu ft @ 32hz w/ 66" of port each.
Model #1

Model #2

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 10+ year member]

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 10+ year member]

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 5,000+ posts]

try to keep the sub away from the port opening inside the box

 

[kicker06 10+ year member]

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 5,000+ posts]

when you say near the front do you mean near the port or side opposite the port.

 

[Rzaa 10+ year member]

I'd assume close to the port as illustrated by the picture.

 

[dvrmstrng 5,000+ posts]

is there any disadvantage to mounting the sub directly in the middle...

 

[Rzaa 10+ year member]

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....